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Sample records for biology investigating magnesium

  1. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

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    Berat Barıs BULDUM

    2013-01-01

    Full Text Available Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attractive to designers due to their low density, only two thirds that of aluminium and its alloys [1]. The element and its alloys take a big part of modern industry needs. Especially nowadays magnesium alloys are used in automotive and mechanical (trains and wagons manufacture, because of its lightness and other features. Magnesium and magnesium alloys are the easiest of all metals to machine, allowing machining operations at extremely high speed. All standard machining operations such as turning, drilling, milling, are commonly performed on magnesium parts.

  2. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    OpenAIRE

    Berat Barıs BULDUM; Aydın SIK; Iskender OZKUL

    2013-01-01

    Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attra...

  3. Improved biological performance of magnesium by micro-arc oxidation

    Directory of Open Access Journals (Sweden)

    W.H. Ma

    2015-03-01

    Full Text Available Magnesium and its alloys have recently been used in the development of lightweight, biodegradable implant materials. However, the corrosion properties of magnesium limit its clinical application. The purpose of this study was to comprehensively evaluate the degradation behavior and biomechanical properties of magnesium materials treated with micro-arc oxidation (MAO, which is a new promising surface treatment for developing corrosion resistance in magnesium, and to provide a theoretical basis for its further optimization and clinical application. The degradation behavior of MAO-treated magnesium was studied systematically by immersion and electrochemical tests, and its biomechanical performance when exposed to simulated body fluids was evaluated by tensile tests. In addition, the cell toxicity of MAO-treated magnesium samples during the corrosion process was evaluated, and its biocompatibility was investigated under in vivo conditions. The results of this study showed that the oxide coating layers could elevate the corrosion potential of magnesium and reduce its degradation rate. In addition, the MAO-coated sample showed no cytotoxicity and more new bone was formed around it during in vivo degradation. MAO treatment could effectively enhance the corrosion resistance of the magnesium specimen and help to keep its original mechanical properties. The MAO-coated magnesium material had good cytocompatibility and biocompatibility. This technique has an advantage for developing novel implant materials and may potentially be used for future clinical applications.

  4. Improved biological performance of magnesium by micro-arc oxidation.

    Science.gov (United States)

    Ma, W H; Liu, Y J; Wang, W; Zhang, Y Z

    2015-03-01

    Magnesium and its alloys have recently been used in the development of lightweight, biodegradable implant materials. However, the corrosion properties of magnesium limit its clinical application. The purpose of this study was to comprehensively evaluate the degradation behavior and biomechanical properties of magnesium materials treated with micro-arc oxidation (MAO), which is a new promising surface treatment for developing corrosion resistance in magnesium, and to provide a theoretical basis for its further optimization and clinical application. The degradation behavior of MAO-treated magnesium was studied systematically by immersion and electrochemical tests, and its biomechanical performance when exposed to simulated body fluids was evaluated by tensile tests. In addition, the cell toxicity of MAO-treated magnesium samples during the corrosion process was evaluated, and its biocompatibility was investigated under in vivo conditions. The results of this study showed that the oxide coating layers could elevate the corrosion potential of magnesium and reduce its degradation rate. In addition, the MAO-coated sample showed no cytotoxicity and more new bone was formed around it during in vivo degradation. MAO treatment could effectively enhance the corrosion resistance of the magnesium specimen and help to keep its original mechanical properties. The MAO-coated magnesium material had good cytocompatibility and biocompatibility. This technique has an advantage for developing novel implant materials and may potentially be used for future clinical applications. PMID:25517917

  5. Magnesium

    Science.gov (United States)

    ... Consumer Datos en español Health Professional Other Resources Magnesium Fact Sheet for Consumers Have a question? Ask ODS: ods.od.nih.gov/contact What is magnesium and what does it do? Magnesium is a ...

  6. INVESTIGATIONS INTO MAGNESIUM BIOSORPTION BY WASTE BREWERY YEAST SACCHAROMYCES UVARUM

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    Małgorzata Gniewosz

    2007-03-01

    Full Text Available Investigations were carried out into the capacity of waste brewery yeast Saccharomyces uvarum for biosorption of magnesium originated from a solution of dehydrated salt of magnesium chloride, depending on the number of cells and diferent pH of the suspension during 6 hours. The concentration of MgCl2•6H2O in the solution was adjusted so as to maintain a stable content of magnesium as expressed per pure element, i.e. 1.25 g/dm3 of solution. In the first stage, the number of cells was differentiated in yeast slurry through either condensation or dilution. In the second stage, pH of yeast suspension was differentiated (pH 5.5, 6.0 and 7.0 at a constant number of cells. The solutions examined were kept under anaerobic and aerobic conditions. Determination of magnesium content of yeast biomass was carried out with the method of atomic adsorption spectroscopy after 15 min, 1 h, 2 h, 4 h and 6 h of experiments. The highest content of magnesium (13.76 mg/g d.m. was obtained at the lowest number of cells in the solution, i.e. 3.5 × 108 cells/cm3 under aerobic conditions. An increase in solution pH facilitated biosorption of magnesium by the yeast. At pH 7.0, after 6 hours of the experiment, the yeasts contained 15.19 mg Mg/g d.m. when kept under anaerobic conditions and 17.22 mg Mg/g d.m. when kept under aerobic conditions.

  7. Investigations of microstructure and dislocations of cast magnesium alloys

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    T. Tański

    2010-09-01

    Full Text Available Purpose: The microstructures and the dislocation arrangements in the cast magnesium alloy have been investigated using transmission electron microscopy and high-resolution transmission electron microscopy. In this paper are presented also the results of phase morphology investigation of an new developed Mg alloy. Such studies are of great interest for the metal industry, mainly the automobile industry, were the improvement of cast elements quality is crucial for economic and quality reason and depends mainly on properly performed controlling process of the production parameters. There are presented especially the effect of heat treatment on the size and distribution of the precipitation occurred in the matrix.Design/methodology/approach: The basic assumptions of this work are realised an Universal Metallurgical Simulator and Analyzer. The solidification process itself is analysed using the UMSA device by appliance of the Derivative Thermo Analysis. The thermal analysis was performed at a low but regulated cooling rate in a range of 0.2 ºC to ca. 3 ºC. Cooling curve for the thermal analysis was performed using a high sensitivity thermocouples of the K type, covered with a stainless steel sheath. The data were acquired by a high speed data acquisition system linked to a PC computer. Two different types of samples were used, bulk-cylindrical, and thin-walled cylindrical. Metallographic investigation were made on cross section samples of a engine bloc. Non-equilibrium heating and cooling process conditions were applied to achieve changes in shape and distribution of the phases such as Al2Cu and Si.Findings: During the investigation Dislocation networks are found to increase with deformation in all cases. The dislocation networks have been found in the g- Mg17Al12 phase as well as in the matrix in the investigation magnesium alloys. The crystallographic orientation relationship are: (1 01 α-Mg ║ (10 Mg17Al12 and [11 0] α-Mg ║ [111] Mg17Al12

  8. Thermal analytical investigations of the magnesium alloy AZ91

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    K.N. Braszczyńska - Malik

    2007-04-01

    Full Text Available The results of thermal derivative analysis (TDA, differential scanning calorimetric (DSC measurements and microstructure investigations of commercial AZ91 magnesium alloy are presented. The performed examinations allowed to determine the microstructure after solidification process and also precipitation process during continuous heating of supersaturated solid solution. The α-phase and α+γ semi-divorced eutectic were observed in as-cast material, whereas both discontinuous and continuous precipitates of γ phase were revealed after heating supersaturated AZ91 alloy.

  9. Investigation on mechanical behaviour of AM60 magnesium alloys

    OpenAIRE

    Yan, C.; R.X. Bai; Gu, Y. T.; Ma, W. J.

    2008-01-01

    Purpose: In this work, tension, impact, bend and fatigue tests were conducted in an AM60 magnesium alloy. The effects of environmental temperature and loading rates on impact and tension behavior of the alloy were also investigated.Design/methodology/approach: The tests were conducted using an Instron universal testing machine. The loading speed was changed from 1 mm/min to 300 mm/min to gain a better understanding of the effect of strain rate. To understand the failure behavior of this alloy...

  10. Investigation of boron extraction process with aid magnesium hydroxide from mother liquor of boron production

    International Nuclear Information System (INIS)

    Conditions of boron - magnesium concentrate preparation from mother liquor by coprecipitation of borate - ions by magnesium hydroxide are investigated. It is shown that boron - magnesium concentrate and products of its heat treatment at 100 - 500 deg C in water are dissolved partially, and in ammonium citrate - practically completely. Suppositions are made on the composition of the product prepared, on the the structure of its crystal lattice and the processes taking place in it during heat treatment. The conclusion is made on the perspectiveness of processing of mother liquor of boron industry for boron - magnesium concentrate

  11. Investigation on mechanical behaviour of AM60 magnesium alloys

    Directory of Open Access Journals (Sweden)

    C. Yan

    2008-12-01

    Full Text Available Purpose: In this work, tension, impact, bend and fatigue tests were conducted in an AM60 magnesium alloy. The effects of environmental temperature and loading rates on impact and tension behavior of the alloy were also investigated.Design/methodology/approach: The tests were conducted using an Instron universal testing machine. The loading speed was changed from 1 mm/min to 300 mm/min to gain a better understanding of the effect of strain rate. To understand the failure behavior of this alloy at different environmental temperatures, Charpy impact test was conducted in a range of temperatures (-40~35°C. Plane strain fracture toughness (KIC was evaluated using compact tension (CT specimen. To gain a better understanding of the failure mechanisms, all fracture surfaces were observed using scanning electron microscopy (SEM. In addition, fatigue behavior of this alloy was estimated using tension test under tension-tension condition at 30 Hz. The stress amplitude was selected in the range of 20~50 MPa to obtain the S-N curve.Findings: The tensile test indicated that the mechanical properties were not sensitive to the strain rates applied (3.3x10-4~0.1 and the plastic deformation was dominated by twining mediated slip. The impact energy is not sensitive to the environmental temperature. The plane strain fracture toughness and fatigue limit were evaluated and the average values were 7.6 MPa.m1/2 and 25 MPa, respectively. Practical implications: Tested materials AM60 Mg alloy can be applied among others in automotive industry aerospace, communication and computer industry.Originality/value: Many investigations have been conducted to develop new Mg alloys with improved stiffness and ductility. On the other hand, relatively less attention has been paid to the failure mechanisms of Mg alloys, such as brittle fracture and fatigue, subjected to different environmental or loading conditions. In this work, tension, impact, bend and fatigue tests were conducted

  12. Electrochemical investigations on magnesium/N-halogen organic cell systems

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    Udhayan, R.; Bhatt, D.P. (Central Electrochemical Research Inst., Karaikudi (India))

    1992-09-01

    This paper reports the results of the experimental studies on various magnesium/magnesium perchlorate/N-halogen organic cell systems employing a constant current discharge method. Several battery parameters, viz. internal resistance, capacity, energy density and coulombic efficiency have been calculated. High open circuit potential (around 1000 mV), open circuit voltage (2.45-2.67 V) and closed circuit voltage (2.30-2.44 V) and non-toxicity are the important and attractive features of these organic cell systems. The trend of the capacities of various magnesium cell systems with respect to the chosen N-halogen organic cathodes is obtained as follows: N,N'-dichlorodimethylhydantoin (DDH) > trichloroisocyanuric acid (TCIA) > dichloroisocyanuric acid (DCIA) > trichloro melamine (TCM). The energy densities of DDH, TCIA, DCIA and TCM based cells are found to be 798, 660, 420 and 95 Wh (kg of N-halogen organic compound){sup -1}, respectively. Cyclic voltammetric behaviour of a typical compound, viz. N,N'-dichlorodimethylhydantoin, has also been studied. (Author).

  13. X-ray photoelectron spectroscopy (XPS) investigation of the surface film on magnesium powders.

    Science.gov (United States)

    Burke, Paul J; Bayindir, Zeynel; Kipouros, Georges J

    2012-05-01

    Magnesium (Mg) and its alloys are attractive for use in automotive and aerospace applications because of their low density and good mechanical properties. However, difficulty in forming magnesium and the limited number of available commercial alloys limit their use. Powder metallurgy may be a suitable solution for forming near-net-shape parts. However, sintering pure magnesium presents difficulties due to surface film that forms on the magnesium powder particles. The present work investigates the composition of the surface film that forms on the surface of pure magnesium powders exposed to atmospheric conditions and on pure magnesium powders after compaction under uniaxial pressing at a pressure of 500 MPa and sintering under argon at 600 °C for 40 minutes. Initially, focused ion beam microscopy was utilized to determine the thickness of the surface layer of the magnesium powder and found it to be ~10 nm. The X-ray photoelectron analysis of the green magnesium sample prior to sintering confirmed the presence of MgO, MgCO(3)·3H(2)O, and Mg(OH)(2) in the surface layer of the powder with a core of pure magnesium. The outer portion of the surface layer was found to contain MgCO(3)·3H(2)O and Mg(OH)(2), while the inner portion of the layer is primarily MgO. After sintering, the MgCO(3)·3H(2)O was found to be almost completely absent, and the amount of Mg(OH)(2) was also decreased significantly. This is postulated to occur by decomposition of the compounds to MgO and gases during the high temperature of sintering. An increase in the MgO content after sintering supports this theory. PMID:22524956

  14. Electrochemical investigations of magnesium in DMEM with biodegradable polycaprolactone coating as corrosion barrier

    Science.gov (United States)

    Degner, Julia; Singer, Ferdinand; Cordero, Luis; Boccaccini, Aldo R.; Virtanen, Sannakaisa

    2013-10-01

    Magnesium and its alloys are being increasingly investigated as biodegradable metallic implant materials. However, the high corrosion rate and accumulation of hydrogen gas upon degradation prevent the clinical application of many magnesium based materials. Applying polymer or ceramic coatings is a popular approach to improve the corrosion behaviour of magnesium and its alloys. In the current research, a biodegradable polymer film of polycaprolactone (PCL) is prepared in different concentrations by spin coating, in order to influence the corrosion behaviour of 99.9% pure magnesium. The resulting polymer coating was qualified by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and tape-test according to ASTM D3359-09 to measure the adhesion strength of the coating on the substrate. Furthermore, coated and uncoated specimens were stored up to 30 days at 37 ̊C in DMEM. The corrosion behaviour was investigated by polarization curves. The PCL-films were found to be uniform and without pores, but they show a low adhesion strength on the substrate. Nevertheless, remarkable improvement of the corrosion resistance of magnesium substrate can be obtained by the polymer films, depending on the film thickness and exposition time. In summary, coating magnesium with PCL is a promising method to tailor the degradation behaviour for biomedical applications.

  15. Electrochemical investigations of magnesium in DMEM with biodegradable polycaprolactone coating as corrosion barrier

    Energy Technology Data Exchange (ETDEWEB)

    Degner, Julia; Singer, Ferdinand [Department of Materials Science, WW4-LKO, University of Erlangen-Nuremberg, Martenstr. 7, 91058 Erlangen (Germany); Cordero, Luis; Boccaccini, Aldo R. [Department of Materials Science, WW7-BioMat, University of Erlangen-Nuremberg, Cauerstr. 6, 91058 Erlangen (Germany); Virtanen, Sannakaisa, E-mail: Virtanen@ww.uni-erlangen.de [Department of Materials Science, WW4-LKO, University of Erlangen-Nuremberg, Martenstr. 7, 91058 Erlangen (Germany)

    2013-10-01

    Magnesium and its alloys are being increasingly investigated as biodegradable metallic implant materials. However, the high corrosion rate and accumulation of hydrogen gas upon degradation prevent the clinical application of many magnesium based materials. Applying polymer or ceramic coatings is a popular approach to improve the corrosion behaviour of magnesium and its alloys. In the current research, a biodegradable polymer film of polycaprolactone (PCL) is prepared in different concentrations by spin coating, in order to influence the corrosion behaviour of 99.9% pure magnesium. The resulting polymer coating was qualified by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and tape-test according to (ASTM D3359-09) to measure the adhesion strength of the coating on the substrate. Furthermore, coated and uncoated specimens were stored up to 30 days at 37 {sup o}C in DMEM. The corrosion behaviour was investigated by polarization curves. The PCL-films were found to be uniform and without pores, but they show a low adhesion strength on the substrate. Nevertheless, remarkable improvement of the corrosion resistance of magnesium substrate can be obtained by the polymer films, depending on the film thickness and exposition time. In summary, coating magnesium with PCL is a promising method to tailor the degradation behaviour for biomedical applications.

  16. Electrochemical investigations of magnesium in DMEM with biodegradable polycaprolactone coating as corrosion barrier

    International Nuclear Information System (INIS)

    Magnesium and its alloys are being increasingly investigated as biodegradable metallic implant materials. However, the high corrosion rate and accumulation of hydrogen gas upon degradation prevent the clinical application of many magnesium based materials. Applying polymer or ceramic coatings is a popular approach to improve the corrosion behaviour of magnesium and its alloys. In the current research, a biodegradable polymer film of polycaprolactone (PCL) is prepared in different concentrations by spin coating, in order to influence the corrosion behaviour of 99.9% pure magnesium. The resulting polymer coating was qualified by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and tape-test according to (ASTM D3359-09) to measure the adhesion strength of the coating on the substrate. Furthermore, coated and uncoated specimens were stored up to 30 days at 37 oC in DMEM. The corrosion behaviour was investigated by polarization curves. The PCL-films were found to be uniform and without pores, but they show a low adhesion strength on the substrate. Nevertheless, remarkable improvement of the corrosion resistance of magnesium substrate can be obtained by the polymer films, depending on the film thickness and exposition time. In summary, coating magnesium with PCL is a promising method to tailor the degradation behaviour for biomedical applications.

  17. Lipidomics Investigations in Cell Biology

    OpenAIRE

    YU, Yang

    2014-01-01

    Cell membrane is the biological barrier serving as both territorial defense and the communication hinge for the interior of cell from its surroundings. As building blocks of cellular membranes and also precursor for second messengers, a variety of lipids play essential roles in cellular membrane dynamics as well as important functions such as cell proliferation, apoptosis, signal transduction and membrane trafficking modulation. Lipidomics, representing the systematic and integrative studies ...

  18. Geometric adaption of biodegradable magnesium alloy scaffolds to stabilise biological myocardial grafts. Part I.

    Science.gov (United States)

    Bauer, M; Schilling, T; Weidling, M; Hartung, D; Biskup, Ch; Wriggers, P; Wacker, F; Bach, Fr-W; Haverich, A; Hassel, T

    2014-03-01

    Synthetic patch materials currently in use have major limitations, such as high susceptibility to infections and lack of contractility. Biological grafts are a novel approach to overcome these limitations, but do not always offer sufficient mechanical durability in early stages after implantation. Therefore, a stabilising structure based on resorbable magnesium alloys could support the biological graft until its physiologic remodelling. To prevent early breakage in vivo due to stress of non-determined forming, these scaffolds should be preformed according to the geometry of the targeted myocardial region. Thus, the left ventricular geometry of 28 patients was assessed via standard cardiac magnetic resonance imaging (MRI). The resulting data served as a basis for a finite element simulation (FEM). Calculated stresses and strains of flat and preformed scaffolds were evaluated. Afterwards, the structures were manufactured by abrasive waterjet cutting and preformed according to the MRI data. Finally, the mechanical durability of the preformed and flat structures was compared in an in vitro test rig. The FEM predicted higher durability of the preformed scaffolds, which was proven in the in vitro test. In conclusion, preformed scaffolds provide extended durability and will facilitate more widespread use of regenerative biological grafts for surgical left ventricular reconstruction. PMID:24264726

  19. DNA Barcoding Investigations Bring Biology to Life

    Science.gov (United States)

    Musante, Susan

    2010-01-01

    This article describes how DNA barcoding investigations bring biology to life. Biologists recognize the power of DNA barcoding not just to teach biology through connections to the real world but also to immerse students in the exciting process of science. As an investigator in the Program for the Human Environment at Rockefeller University in New…

  20. X-ray photoelectron spectroscopy investigations of zinc-magnesium alloy coated steel

    International Nuclear Information System (INIS)

    The coating layer composition depth profiles and element chemical states of zinc-magnesium alloy coated steel were investigated by X-ray photoelectron spectroscopy depth profiling. Through the analysis of photoelectron signals and Auger signals of different elements on different depth planes of the coating layer, it can be found that the surface of the coating layer contains MgCO3, MgO, Mg(OH)2, metallic Mg, metallic Zn and some complex zinc compounds. Under the surface, there is a Zn2Mg alloy layer with the thickness of about 300 nm accompanied with MgO and Mg(OH)2 in the layer. There is a transitional layer with the thickness of about 200 nm between the Zn2Mg alloy layer and the pure Zn layer, whose components consist of zinc-magnesium alloy without fixed stoichiometry, a little MgO and a little Mg(OH)2.

  1. Investigation of effect of some factors on boron coprecipitaion from magnesium chloride brines by aluminium hydroxide

    International Nuclear Information System (INIS)

    The conditions of precipitation of boron with aluminium hydroxide from natural magnesium chloride solutions of different concentration and from artificial solutions of boric acid with the same content of magnesium chloride were investigated. The effect of acidity on precipitation of boron with aluminium hydroxide was investigated over the pH range from 4.5 to 8.0. The dependence of the degree of boron extraction on pH has two maxima and one minimum. For concentrated mother liquors the maximum is at pH=5.0, and for dilute ones, at pH=6.5. The nature of the metal hydroxide and of the anions present in the solutions affects the shift of the maximum and minimum of boron extraction. It has been established that with an increase in temperature from 15 deg C to 45 deg C boron precipitation from weakly acid solutions decreases as a result of destruction of the boron polyanions with the formation of orthoboric acid. In a weakly alkaline medium, however, boron extraction increases due to additional release of magnesium hydroxide

  2. Investigation of the neutron contamination in IMRT deliveries with a paired magnesium and boron coated magnesium ionization chamber system

    International Nuclear Information System (INIS)

    Background and Purpose: Photon beams used in IMRT treatments with high energies (>10 MV) are contaminated with neutrons. Measurement of this neutron dose is of significance to the overall risk estimate of high energy radiotherapy. Materials and methods: For measuring neutron doses a paired magnesium and boron coated magnesium chamber system was used. All measurements were performed inside the solid water phantom EasyCube using abdominal extensions. 4 different clinical treatment plans were studied. Results: The measured neutron dose showed to be homogeneous inside the phantom and increased with increased number of applied monitor units. The sum over all fractions showed neutron doses of 1 - 2 mGy, depending on the kind of treatment. Conclusions: Using large conversion factors of 25 Sv/Gy, none of the studied treatment plans exceeded dose equivalents of 50 mSv for the whole treatment. This dose equivalent has to be considered whole body dose due to the homogeneous distribution of neutrons

  3. Preparation and characterization of porous magnesium materials

    Institute of Scientific and Technical Information of China (English)

    LIU Xi-qin; LIU Zi-li; ZHANG Xiao-hong; FENG Jun-dong; YU Ta-xi

    2006-01-01

    The proper spacer material and the preparation technology for biological compatible porous magnesium materials were explored by the powder metallurgy method, and microstructures, porosity and mechanical properties of sintered porous magnesium were investigated. The results show that compared with spacer materials of NH4CO3, NH3Cl and carbamide, NH4CO3 is the best one for preparation of sintered porous magnesium, and the worst one is NH3Cl. The isolated blind pores are formed mainly by the particle interval of the magnesium powders. Adding spacer material favors the formation of open pores, while has little contribution to the formation of blind pores. The overall porosity and porosity of open pore of the sintered porous magnesium increase with the increase of added spacer material, while decrease with the increase of the molding stress. The mechanical properties of sintered porous magnesium increase with decreasing addition of spacer material and increasing molding stress.

  4. Tailoring the degradation and biological response of a magnesium-strontium alloy for potential bone substitute application.

    Science.gov (United States)

    Han, Junjie; Wan, Peng; Ge, Ye; Fan, Xinmin; Tan, Lili; Li, Jianjun; Yang, Ke

    2016-01-01

    Bone defects are very challenging in orthopedic practice. There are many practical and clinical shortcomings in the repair of the defect by using autografts, allografts or xenografts, which continue to motivate the search for better alternatives. The ideal bone grafts should provide mechanical support, fill osseous voids and enhance the bone healing. Biodegradable magnesium-strontium (Mg-Sr) alloys demonstrate good biocompatibility and osteoconductive properties, which are promising biomaterials for bone substitutes. The aim of this study was to evaluate and pair the degradation of Mg-Sr alloys for grafting with their clinical demands. The microstructure and performance of Mg-Sr alloys, in vitro degradation and biological properties including in vitro cytocompatibility and in vivo implantation were investigated. The results showed that the as-cast Mg-Sr alloy exhibited a rapid degradation rate compared with the as-extruded alloy due to the intergranular distribution of the second phase and micro-galvanic corrosion. However, the initial degradation could be tailored by the coating protection, which was proved to be cytocompatible and also suitable for bone repair observed by in vivo implantation. The integrated fracture calluses were formed and bridged the fracture gap without gas bubble accumulation, meanwhile the substitutes simultaneously degraded. In conclusion, the as-cast Mg-Sr alloy with coating is potential to be used for bone substitute alternative. PMID:26478374

  5. Application of INAA for investigation of magnesium and aluminium oxide materials

    International Nuclear Information System (INIS)

    The paper presents investigations of changes in optical absorption and photo luminescence spectra of magnesium oxide, and natural and synthetic magnesium aluminium spinel related with the content of transition metal ions (Cr, Fe, Mn) and the irradiation with fast neutrons. Six synthetic single magnesium aluminium spinel crystals with different stoichiometry (MgO·nAl2O3), five natural crystals from Ural and Pamir deposits, and seven MgO crystals were studied. Micro impurities (Cr, Fe, and Mn) and macro component (Mg, Al) quantities have been determined using the instrumental neutron activation analysis technique. Concentrations of impurities in different spinels were found in following ranges: for Cr-1 × 10-4 to 8 × 10-2 %, for Mn-2 × 10-5 to 23 %, for Fe-1 × 10-4 to 1.2 %. Three ranges of luminescence: 380-460, 650-850 and 850-1,050 nm, were established in the most part of the investigated MgO samples. Analysis shows that the intensity of emission in each of these regions is strongly dependent on the concentration of transition metal ions. Great deviation from the stoichiometry of the irradiated MgO·2.8Al2O3 crystal leads to the local structure of α-Al2O3 formation around Cr3+ ions. The orange emission is attributed to Mn2+ in octahedral coordination, it can be assumed that the band at 570 nm is belonging to the complex centre 'Mn2+-F+ (or F centre)'. (author)

  6. Investigation on the Explosive Welding of 1100 Aluminum Alloy and AZ31 Magnesium Alloy

    Science.gov (United States)

    Chen, Pengwan; Feng, Jianrui; Zhou, Qiang; An, Erfeng; Li, Jingbo; Yuan, Yuan; Ou, Sanli

    2016-07-01

    The undesirable properties of magnesium alloys include easy embrittlement, low oxidation resistance, and difficulty in welding with other materials. Their application in industry is, therefore, restricted. In this paper, plates of 1100 aluminum alloy and AZ31 magnesium alloy were successfully welded together using the explosive welding technique. The influences of the welding parameters on the weld quality were investigated. The surface morphology and microstructure near the weld interface were examined by optical microscopy, scanning electron microscopy (equipped with energy-dispersive x-ray spectroscopy), and transmission electron microscopy. The experimental results demonstrated the typical wavy bonding interface. In addition, elemental diffusion with a thickness of approximately 3 μm occurred near the bonding interface. The two plates were joined together well at the atomic scale. Nanograins with a size of approximately 5 nm were observed in the diffusion layer. The microhardness and shear strength were measured to evaluate the mechanical properties, which confirmed that a high quality of bonding was acquired.

  7. Investigation on the Explosive Welding of 1100 Aluminum Alloy and AZ31 Magnesium Alloy

    Science.gov (United States)

    Chen, Pengwan; Feng, Jianrui; Zhou, Qiang; An, Erfeng; Li, Jingbo; Yuan, Yuan; Ou, Sanli

    2016-06-01

    The undesirable properties of magnesium alloys include easy embrittlement, low oxidation resistance, and difficulty in welding with other materials. Their application in industry is, therefore, restricted. In this paper, plates of 1100 aluminum alloy and AZ31 magnesium alloy were successfully welded together using the explosive welding technique. The influences of the welding parameters on the weld quality were investigated. The surface morphology and microstructure near the weld interface were examined by optical microscopy, scanning electron microscopy (equipped with energy-dispersive x-ray spectroscopy), and transmission electron microscopy. The experimental results demonstrated the typical wavy bonding interface. In addition, elemental diffusion with a thickness of approximately 3 μm occurred near the bonding interface. The two plates were joined together well at the atomic scale. Nanograins with a size of approximately 5 nm were observed in the diffusion layer. The microhardness and shear strength were measured to evaluate the mechanical properties, which confirmed that a high quality of bonding was acquired.

  8. X-ray photoelectron spectroscopy investigations of zinc-magnesium alloy coated steel

    Energy Technology Data Exchange (ETDEWEB)

    Chen Sheng, E-mail: chen_sheng@baosteel.com [Research Institute of Baoshan Iron and Steel Co. Ltd., 655 Fujin Road, Baoshan District, Shanghai 201900 (China); Yan Fei; Xue Fei; Yang Lihong; Liu Junliang [Research Institute of Baoshan Iron and Steel Co. Ltd., 655 Fujin Road, Baoshan District, Shanghai 201900 (China)

    2010-11-01

    The coating layer composition depth profiles and element chemical states of zinc-magnesium alloy coated steel were investigated by X-ray photoelectron spectroscopy depth profiling. Through the analysis of photoelectron signals and Auger signals of different elements on different depth planes of the coating layer, it can be found that the surface of the coating layer contains MgCO{sub 3}, MgO, Mg(OH){sub 2}, metallic Mg, metallic Zn and some complex zinc compounds. Under the surface, there is a Zn{sub 2}Mg alloy layer with the thickness of about 300 nm accompanied with MgO and Mg(OH){sub 2} in the layer. There is a transitional layer with the thickness of about 200 nm between the Zn{sub 2}Mg alloy layer and the pure Zn layer, whose components consist of zinc-magnesium alloy without fixed stoichiometry, a little MgO and a little Mg(OH){sub 2}.

  9. INVESTIGATION OF LASER BEAM WELDING PROCESS OF AZ61 MAGNESIUM-BASED ALLOY

    Institute of Scientific and Technical Information of China (English)

    H.Y. Wang; Z.J. Li

    2006-01-01

    Laser welding process of AZ61 magnesium alloys is investigated using a special CO2 laser experimental system. The effect of processing parameters including laser power, welding speed,and protection gas flow at the top and bottom is researched The results show that an ideal weld bead can be formed by choosing the processing parameters properly. An optimized parameter range is obtained by a large number of experiments. Among them, laser power and welding speed are the two main parameters that determine the weld width and dimensions. The protect gas flow rate has a slight effect on the weld width, but it directly effects the surface color of the weld. The test results for typical welds indicate that the microhardness and tensile strength of the weld zone are better than that of the base metal. A fine-grained weld region has been observed and no obvious heat-affected zone is found. The weld zone mainly consists of small α-Mg phase, (α +Al12Mg17), and other eutectic phases. The small grains and the eutectic phases in the joint are believed to play an important role in the increase of the strength of welds for AZ61 magnesium alloys.

  10. Friction Stir Lap Welding of Magnesium Alloy to Steel: A Preliminary Investigation

    Science.gov (United States)

    Jana, S.; Hovanski, Y.; Grant, G. J.

    2010-12-01

    An initial study was made to evaluate the feasibility of joining magnesium alloy AZ31 sheet to galvanized steel sheet in a lap configuration using friction stir welding (FSW). Two different automotive sheet steels were used for comparative evaluation of the dissimilar joining potential: a 0.8 mm thick, electrogalvanized (EG) mild steel, and a 1.5 mm thick hot-dipped galvanized (HDG) high-strength, low-alloy (HSLA) steel. These steels were joined to 2.33 mm thick AZ31B magnesium sheet. A single FSW tool design was used for both dissimilar welds, and the process parameters were kept the same. The average peak load for the AZ31-1.5 mm steel weld joint in lap shear mode was found to be 6.3 ± 1.0 kN. For the AZ31-0.8 mm steel weld, joint strength was 5.1 ± 1.5 kN. Microstructural investigation indicates melting of the Zn coating present on the steel sheets, and subsequent alloying with the Mg sheet resulted in the formation of a solidified Zn-Mg alloy layer.

  11. Friction Stir Lap Welding of Magnesium Alloy to Steel: A Preliminary Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Saumyadeep; Hovanski, Yuri; Grant, Glenn J.

    2010-12-01

    An initial study was made to evaluate the feasibility of joining Magnesium alloy AZ31 sheet to galvanized steel sheet in lap configuration using friction stir welding (FSW). Two different automotive sheet steels were used for comparative evaluation of the dissimilar joining potential; a 0.8mm thick, electro galvanized (EG) mild steel, and a 1.5mm thick hot dipped galvanized (HDG) high-strength, low-alloy steel (HSLA). These steels were joined to 2.33mm thick AZ31B magnesium sheet. A single FSW tool design was used for both dissimilar welds, and process parameters were kept the same. Average peak load for the AZ31-1.5 mm steel weld joint in lap shear mode was found to be 6.3 ± 1.0 kN. For the AZ31-0.8 mm steel weld, joint strength was 5.1 ± 1.5 kN. Microstructural investigation indicates melting of the Zn coating at the interface and subsequent alloying with the Mg sheet resulting in formation of solidified Zn-Mg alloy layer at AZ31/steel interface.

  12. Nutrition and magnesium absorption.

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true magnesium abs

  13. Magnesium Gluconate

    Science.gov (United States)

    Magnesium gluconate is used to treat low blood magnesium. Low blood magnesium is caused by gastrointestinal disorders, prolonged vomiting or ... disease, or certain other conditions. Certain drugs lower magnesium levels as well.This medication is sometimes prescribed ...

  14. Nutrition and magnesium absorption.

    OpenAIRE

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true magnesium absorption was neither affected by soybean protein in the diet nor by supplemental phytate. The inhibitory influence of soybean protein and phytate on apparent magnesium absorption was found to be cau...

  15. Investigation of influence of medium pH and sulfate ion concentrations on corrosion behavior of magnesium alloy ZE41

    International Nuclear Information System (INIS)

    Magnesium alloys have emerged as potential structural materials with all capabilities to even replace close contenders; aluminium alloys in weight-critical applications. High susceptibility to corrosion being the only limitation, corrosion of magnesium alloys continues to gather much attention among the material scientists worldwide. ZE41 is one such alloy of magnesium which is increasingly gaining importance as automobile and aerospace material. In the present study the influence of the medium pH and sulfate ion concentrations on the corrosion behavior of magnesium alloy ZE41 has been investigated using electrochemical techniques like the Tafel extrapolation and electrochemical impedance spectroscopy (EIS). The tests have been carried out in a range of conditions, with gradually varying pH and sulfate ion concentration. The morphology and composition of the corroded alloy surface have been determined by the scanning electron microscopy (SEM) and energy dispersion X-ray (EDX) analysis, respectively. The recorded results reflect a trend of a higher corrosion rate associated with a higher sulfate concentration at each pH and with a lower pH at each sulfate concentration. (authors)

  16. Investigating Coccolithophorid Biology in the Sedimentary Laboratory

    Science.gov (United States)

    McClelland, H. L. O.; Barbarin, N.; Beaufort, L.; Hermoso, M.; Rickaby, R. E. M.

    2014-12-01

    Coccolithophores are the ocean's dominant calcifying phytoplankton; they play an important, but poorly understood, role in long-term biogeochemical climatic feedbacks. Calcite producing marine organisms are likely to calcify less in a future world where higher carbon dioxide concentrations will lead to ocean acidification (OA), but coccolithophores may be the exception. In coccolithophores calcification occurs in an intracellular vesicle, where the site of calcite precipitation is buffered from the external environment and is subject to a uniquely high degree of biological control. Culture manipulation experiments mimicking the effects of OA in the laboratory have yielded empirical evidence for phenotypic plasticity, competition and evolutionary adaptation in asexual populations. However, the extent to which these results are representative of natural populations, and of the response over timescales of greater than a few hundred generations, is unclear. Here we describe a new sediment-based proxy for the PIC:POC (particulate inorganic to particulate organic carbon ratio) of coccolithophore biomass, which is equivalent to the fractional energy contribution to calcification at constant pH, and a biologically meaningful measure of the organism's tendency to calcify. Employing the geological record as a laboratory, we apply this proxy to sedimentary material from the southern Pacific Ocean to investigate the integrated response of real ancient coccolithophore populations to environmental change over many thousands of years. Our results provide a new perspective on phenotypic change in real populations of coccolithophorid algae over long timescales.

  17. Time Dependent Magnesium AZ31B Behavior: Experimental and Physically based Modeling Investigation

    Science.gov (United States)

    Rodriguez, A. K.; Ayoub, G.; Kridli, G.; Zbib, H.

    The need to produce vehicles with improved fuel efficiency and reduced emissions has led the automotive industry to consider use of "lightweighting" materials in the construction of automotive body and chassis systems. For automotive body structures and closure panel applications, mostly made of sheet, aluminum alloys are being introduced due to their lower densities and relatively high specific strengths, as well as their compatibility with the traditional manufacturing process that are used with steel. However, interest has been increasingly focusing on the use of sheet magnesium in the manufacturing of panels and structural components, since its density is about 40% lower compared to aluminum. Accordingly, the objectives of this study are to investigate the evolution of microstructure during thermo-mechanical processing of twin-roll cast AZ31B alloys sheets, and to examine the mechanical properties of the alloy under superplastic conditions. The rate dependent crystal plasticity model have been used and integrated using an explicit model was coupled with the Taylor polycrystal model in the aim to capture the overall behavior of our studied material.

  18. 镁离子浓度对SBR生物除磷系统的影响%Effect of Magnesium Iron Content on the Biological Phosphorus Removal System in SBR

    Institute of Scientific and Technical Information of China (English)

    李幸; 高大文; 刘琳

    2011-01-01

    通过不投加镁离子(R1)、投加8 mg/L镁离子(R2)以及投加24 mg/L镁离子(R3),分析镁离子对SBR生物除磷体系的影响.结果表明,适量镁离子的添加会加速聚磷菌的富集,有助于维持生物除磷系统的稳定运行.在稳定运行阶段,镁离子不充足的系统(R1)磷酸盐去除率逐渐下降至50%以下,系统呈恶化趋势,而在镁离子充足的体系(R2和R3)中,一直保持较好的磷酸盐去除效果,磷酸盐去除率在90%以上,同时磷酸盐的变化同镁离子的浓度变化呈现相似的趋势,R2和R3的Mg/P值分别为0.29~0.59和0.25~0.%This study investigated the effect of magnesium iron content on the enhanced biological phosphorus removal system,which performed differently at magnesium content of 0 mg/L,8 mg/L and 24 mg/L(R1-R3).The results indicated appropriate Mg addition could enrich phosphorus accumulating organisms and keep stable running.During the steady state period,phosphorus removal rate declined to below 50% gradually,moreover,the system tended to deteriorate with the shortage of magnesium in R1.However,the system with appropriate magnesium kept the higher phosphorus removal rate(more than 90%).The statistical analysis of the experimental data also showed a strong correlation between Mg and phosphorus concentrations in R2 and R3,the ratios of Mg and P were 0.29-0.59 and 0.25-0.54 in two reactors respectively.In the anaerobic phase of EBPR,the magnesium content,the absolute value of ORP and the phosphates release had a correlation.Meanwhile,magnesium was released together with phosphates in the anaerobic phase,and that would uptake under aerobic conditions.Thus it was obvious that magnesium played a key role on the biological phosphorus removal system.

  19. Synthesis, characterization and biological evaluation of strontium/magnesium-co-substituted hydroxyapatite.

    Science.gov (United States)

    Geng, Zhen; Wang, Renfeng; Li, Zhaoyang; Cui, Zhenduo; Zhu, Shengli; Liang, Yanqin; Liu, Yunde; Huijing, Bao; Li, Xue; Huo, Qianyu; Liu, Zhili; Yang, Xianjin

    2016-07-01

    The present study aims to investigate the contribution of two biologically important cations, Mg(2+) and Sr(2+), when co-substituted into the structure of hydroxyapatite (Ca10(PO4)6(OH)2, HA). The substituted samples were synthesized by a hydrothermal method that involved the addition of Mg(2+) and Sr(2+) containing precursors to partially replace Ca(2+) in the apatite structure. Four co-substituted HA samples with different concentrations of Mg(2+) and Sr(2+) ((Mg + Sr)/(Mg + Sr + Ca) = 30%) were investigated, and they were compared with pure HA. Experimental results showed that only a limited amount of Mg (Mg/(Mg + Ca + Sr) < 14%) could successfully substitute for Ca in HA. In addition, Mg substitution resulted in reduced crystallinity, thermal stability and lattice parameters of HA. In contrast, Sr could fully substitute for Ca. Furthermore, the addition of Sr increased the lattice parameters of HA. Here, we obtained the cation leach liquor by immersing the prepared samples in a culture medium for cell experiments. The in vitro study showed that 10Mg20Sr promoted better MG63 cell attachment, proliferation and differentiation than HA. Thus, the presence of an appropriate proportion of Mg and Sr could play a significant role in the increased biocompatibility of HA. PMID:26916949

  20. Calcium phosphate coating on magnesium alloy by biomimetic method :Investigation of morphology ,composition and formation process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Magnesium alloy has similar mechanical properties with natural bone and can degrade via corrosion in the electrolytic environment of the human body.Calcium phosphate has been proven to possess bioactivity and bone inductivity.In order to integrate both advantages,calcium phosphate coating was fabricated on magnesium alloy by a biomimetic method.Supersaturated calcification solutions (SCSs) with different Ca/P ratio and C1- concentration were used as mimetic solutions.The morphology,composition and formation process of the coating were studied with scanning electron microscopy (SEM),energy dispersive spectrometer (EDS),Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD).The results show that a uniform calcium phosphate coating was observed on magnesium alloy,the properties of which could be adjusted by the SCSs with different Ca/P ratio.The formation process of the coating was explored by immersing magnesium alloy in SCSs with different Cl- concentration which could adjust the hydrogen production.According to SEM results,the hydrogen bubbles were associated with the formation of grass-like and flower-like coating morphologies.In conclusion,the biomimetic method was effective to form calcium phosphate coating on magnesium alloy and the morphology and composition of the coating could be accommodated by the Ca/P ratio and Cl- concentration in SCSs.

  1. In-situ neutron diffraction and acoustic emission investigation of twinning activity in magnesium

    Czech Academy of Sciences Publication Activity Database

    Máthis, K.; Beran, Přemysl; Čapek, J.; Lukáš, Petr

    2012-01-01

    Roč. 340, 012096 (2012), s. 1-6. ISSN 1742-6588. [5th European Conference on Neutron Scattering. Praha, 17.07.2011-21.07.2011] Institutional support: RVO:61389005 Keywords : magnesium alloys * twinning * compression * tension * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism

  2. Hydro biological investigations of lake Drukshiai

    International Nuclear Information System (INIS)

    Purposes of this research were to investigate changes in the physical, chemical and tropic conditions of Lake Drukshiai caused by the combined effect of Ignalina NPP and how it effects on structures and function of biocenoses; to estimate the influence of phytocenoses, zoocenoses and bacteriocenoses on the quality of water in Lake Drukshiai; to estimate the eco toxicological state of Lake Drukshiai. According to the complex hydro biological investigations on Lake Drukshiai - Ignalina NPP cooler great changes in planktonic organism community, tendencies of those changes in different ecological zones were evaluated in 1993 - 1997. The amount of species of most dominant planktonic organisms in 1993 - 1997 decreased 2-3 times in comparison with that before Ignalina NPP operation: phytoplankton from 116 to 40 - 50, zooplankton - from 233 to 139. The organic matter increasing tendency was determined in bottom sediments of the lake. The highest amount of it was evaluated in the south - eastern part of the lake. 69 water macrophyte species were found in bottom sediments during the investigation period. 16 species were not found in this lake earlier. Abundance of filamentous green algae was registered.The rates of fish communities successional transformation were ten times in excess of those of the given processes in natural lakes. Moreover the comparison of results on Lake Drukshiai bioindication analysis with changes of comparable bio markers which were obtained from other water systems of Lithuania, Switzerland, Sweden and Poland, including those with active nuclear power plants in their environment was carried out. It was determined that the functional and structural changes in Lake Drukshiai biota are mostly caused by chemical pollution. It was found out that the frequency of cytogenetic damage emerged as a specific radionuclide - caused effect in aquatic organisms inhabiting Lake Drukshiai, is slightly above the background level and is 5 times lower than the same

  3. Magnesium Oxide

    Science.gov (United States)

    Magnesium is an element your body needs to function normally. Magnesium oxide may be used for different reasons. Some ... to relieve heartburn, sour stomach, or acid indigestion. Magnesium oxide also may be used as a laxative ...

  4. Magnesium Metabolism

    OpenAIRE

    2008-01-01

    Magnesium is the second most common intracellular divalent cation. Magnesium balance in the body is controlled by a dynamic interplay among intestinal absorption, exchange with bone, and renal excretion. Intestinal magnesium absorption proceeds in both a passive paracellular and an active transcellular manner. Regulation of serum magnesium concentrations is achieved mainly by control of renal magnesium reabsorption. Only 20% of filtered magnesium is reabsorbed in the proximal tubule, whereas ...

  5. Effect of oxygen on the hydrogenation properties of magnesium films

    DEFF Research Database (Denmark)

    Ostenfeld, Christopher Worsøe; Chorkendorff, Ib

    2006-01-01

    The effect of magnesium oxide on the magnesium and hydrogen desorption properties of magnesium films have been investigated. We find that by capping metallic magnesium films with oxide overlayers the apparent desorption energy of magnesium is increased from 146 kJ/mol to 314 kJ/mol. The results...... are discussed in light of previous investigations of ball-milled magnesium powders....

  6. Determination of isotope enrichments of magnesium in microwave-digested biological samples by thermal ionization mass spectrometry using a direct loading technique

    International Nuclear Information System (INIS)

    The isotope ratios of magnesium were determined in isotopically normal and 26Mg-enriched samples of human blood, blood plasma, urine and faeces and bovine muscle. The measurements were made with a magnetic sector, thermal ionization mass spectrometer (TIMS) equipped with a multiple ion collector system for simultaneous detection of the ion currents. The samples were decomposed using microwave digestion with HNO3 and HCl. Without further chemical treatment, the mineralized samples were deposited together with silica gel and boric acid on rhenium filaments, which served as thermal ionization source filaments. This method, called the direct loading technique (DLT), results in stable ion signals of the magnesium isotopes with isotope ratios indistinguishable from those of natural Mg standards within experimental error. Fractionation-corrected 26Mg/24Mg ratios of natural Mg standards were determined with a relative external precision of 0.02%. The magnesium recoveries for all of the analysed matrices were ≥ 97%; 26Mg was added to calibrated sample solutions to produce isotopic enrichments within a range typically appearing in samples of human tracer studies. Linear regression analysis of measured versus expected per 1000(%o) enrichments yields y = 0.998x + 0.79. The DLT described here is a simpler and quicker method than other methods reported hitherto. It has the advantage of avoiding magnesium separation and purification steps prior to TIMS analysis of all of the analysed biological samples and thus reduces contamination and guarantees optimum magnesium recovery. The reported method improves the applicability of stable isotopes of magnesium in human tracer studies. (Author)

  7. Structure and Properties Investigation of MCMgAl12Zn1 Magnesium Alloy

    OpenAIRE

    L.A. Dobrzański; M. Król

    2013-01-01

    This work presents an influence of cooling rate on crystallization process, structure and mechanical properties of MCMgAl12Zn1 castmagnesium alloy. The experiments were performed using the novel Universal Metallurgical Simulator and Analyzer Platform. Theapparatus enabled recording the temperature during refrigerate magnesium alloy with three different cooling rates, i.e. 0.6, 1.2 and 2.4C/s and calculate a first derivative. Based on first derivative results, nucleation temperature, beginnin...

  8. Investigation of Twinning Activity in Magnesium Using Advanced In-Situ Methods

    Czech Academy of Sciences Publication Activity Database

    Máthis, K.; Čapek, J.; Lukáš, Petr; Brownd, D.; Clausen, B.

    Vol. 765. Stafa-Zurich : TRANS TECH PUBLICATIONS LTD, 2013, s. 532-536. ISSN 0255-5476. [6th International Light Metals Technology Conference (LMT 2013). Brunel Unversity, Old Windsor (GB), 24.07.2013-26.07.2013] R&D Projects: GA ČR(CZ) GAP204/12/1360 Institutional support: RVO:61389005 Keywords : magnesium * acoustic emission * neutron diffraction * twinning * elastic-plastic self-consistent (EPSC) model Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  9. An investigation of strontium nitrite and its role in the ageing of the magnesium-strontium nitrate pyrotechnic system using isothermal microcalorimetry and thermal analysis techniques

    Energy Technology Data Exchange (ETDEWEB)

    Tuukkanen, I.M. [Defence Forces Materiel Command, P.O. Box 69, FIN-33541 Tampere (Finland); Charsley, E.L. [Centre for Thermal Studies, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH (United Kingdom)]. E-mail: e.l.charsley@hud.ac.uk; Goodall, S.J. [Centre for Thermal Studies, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH (United Kingdom); Laye, P.G. [Centre for Thermal Studies, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH (United Kingdom); Rooney, J.J. [Centre for Thermal Studies, University of Huddersfield, Queensgate, Huddersfield, West Yorkshire HD1 3DH (United Kingdom); Griffiths, T.T. [QinetiQ Ltd., Fort Halstead, Sevenoaks, Kent TN14 7BP (United Kingdom); Lemmetyinen, H. [Institute of Materials Chemistry, Tampere University of Technology, P.O. Box 527, FIN-33101 Tampere (Finland)

    2006-04-01

    A sample of strontium nitrite has been synthesised and thermally characterised to investigate its role in the ageing of magnesium-strontium nitrate pyrotechnic compositions in the presence of water vapour. Studies by isothermal microcalorimetry show that the addition of strontium nitrite to a 50% magnesium-50% strontium nitrate composition eliminated the induction reaction normally observed in closed ampoule studies in air at 50 deg. C and relative humidities in the range 65-69%.

  10. An investigation of strontium nitrite and its role in the ageing of the magnesium-strontium nitrate pyrotechnic system using isothermal microcalorimetry and thermal analysis techniques

    International Nuclear Information System (INIS)

    A sample of strontium nitrite has been synthesised and thermally characterised to investigate its role in the ageing of magnesium-strontium nitrate pyrotechnic compositions in the presence of water vapour. Studies by isothermal microcalorimetry show that the addition of strontium nitrite to a 50% magnesium-50% strontium nitrate composition eliminated the induction reaction normally observed in closed ampoule studies in air at 50 deg. C and relative humidities in the range 65-69%

  11. Magnesium basics

    OpenAIRE

    Jahnen-Dechent, Wilhelm; Ketteler, Markus

    2012-01-01

    As a cofactor in numerous enzymatic reactions, magnesium fulfils various intracellular physiological functions. Thus, imbalance in magnesium status—primarily hypomagnesaemia as it is seen more often than hypermagnesaemia—might result in unwanted neuromuscular, cardiac or nervous disorders. Measuring total serum magnesium is a feasible and affordable way to monitor changes in magnesium status, although it does not necessarily reflect total body magnesium content. The following review focuses o...

  12. Theoretical investigation of zero field splitting parameter of Cr3+ doped diammonium hexaaqua magnesium sulfate

    International Nuclear Information System (INIS)

    The zero field splitting parameter D of Cr3+ doped diammonium hexaaqua magnesium sulfate (DHMS) are calculated with perturbation formula using crystal field (CF) parameters from superposition model. The theoretically calculated ZFS parameters for Cr3+ in DHMS single crystal are compared with the experimental value obtained by electron paramagnetic resonance (EPR). The theoretical ZFS parameter D is similar to that from experiment. The energy band positions of optical absorption spectra of Cr3+ doped DHMS single crystal are calculated with CFA package, which are in good match with experimental values

  13. Adaptable data management for systems biology investigations

    Directory of Open Access Journals (Sweden)

    Burdick David

    2009-03-01

    Full Text Available Abstract Background Within research each experiment is different, the focus changes and the data is generated from a continually evolving barrage of technologies. There is a continual introduction of new techniques whose usage ranges from in-house protocols through to high-throughput instrumentation. To support these requirements data management systems are needed that can be rapidly built and readily adapted for new usage. Results The adaptable data management system discussed is designed to support the seamless mining and analysis of biological experiment data that is commonly used in systems biology (e.g. ChIP-chip, gene expression, proteomics, imaging, flow cytometry. We use different content graphs to represent different views upon the data. These views are designed for different roles: equipment specific views are used to gather instrumentation information; data processing oriented views are provided to enable the rapid development of analysis applications; and research project specific views are used to organize information for individual research experiments. This management system allows for both the rapid introduction of new types of information and the evolution of the knowledge it represents. Conclusion Data management is an important aspect of any research enterprise. It is the foundation on which most applications are built, and must be easily extended to serve new functionality for new scientific areas. We have found that adopting a three-tier architecture for data management, built around distributed standardized content repositories, allows us to rapidly develop new applications to support a diverse user community.

  14. Printable Bioelectronics To Investigate Functional Biological Interfaces.

    Science.gov (United States)

    Manoli, Kyriaki; Magliulo, Maria; Mulla, Mohammad Yusuf; Singh, Mandeep; Sabbatini, Luigia; Palazzo, Gerardo; Torsi, Luisa

    2015-10-19

    Thin-film transistors can be used as high-performance bioelectronic devices to accomplish tasks such as sensing or controlling the release of biological species as well as transducing the electrical activity of cells or even organs, such as the brain. Organic, graphene, or zinc oxide are used as convenient printable semiconducting layers and can lead to high-performance low-cost bioelectronic sensing devices that are potentially very useful for point-of-care applications. Among others, electrolyte-gated transistors are of interest as they can be operated as capacitance-modulated devices, because of the high capacitance of their charge double layers. Specifically, it is the capacitance of the biolayer, being lowest in a series of capacitors, which controls the output current of the device. Such an occurrence allows for extremely high sensitivity towards very weak interactions. All the aspects governing these processes are reviewed here. PMID:26420480

  15. MgF2-coated porous magnesium/alumina scaffolds with improved strength, corrosion resistance, and biological performance for biomedical applications.

    Science.gov (United States)

    Kang, Min-Ho; Jang, Tae-Sik; Kim, Sung Won; Park, Hui-Sun; Song, Juha; Kim, Hyoun-Ee; Jung, Kyung-Hwan; Jung, Hyun-Do

    2016-05-01

    Porous magnesium (Mg) has recently emerged as a promising biodegradable alternative to biometal for bone ingrowth; however, its low mechanical properties and high corrosion rate in biological environments remain problematic. In this study, porous magnesium was implemented in a scaffold that closely mimics the mechanical properties of human bones with a controlled degradation rate and shows good biocompatibility to match the regeneration rate of bone tissue at the affected site. The alumina-reinforced Mg scaffold was produced by spark plasma sintering and coated with magnesium fluoride (MgF2) using a hydrofluoric acid solution to regulate the corrosion rate under physiological conditions. Sodium chloride granules (NaCl), acting as space holders, were leached out to achieve porous samples (60%) presenting an average pore size of 240μm with complete pore interconnectivity. When the alumina content increased from 0 to 5vol%, compressive strength and stiffness rose considerably from 9.5 to 13.8MPa and from 0.24 to 0.40GPa, respectively. Moreover, the biological response evaluated by in vitro cell test and blood test of the MgF2-coated porous Mg composite was enhanced with better corrosion resistance compared with that of uncoated counterparts. Consequently, MgF2-coated porous Mg/alumina composites may be applied in load-bearing biodegradable implants. PMID:26952467

  16. Magnesium for Hydrogen Storage

    DEFF Research Database (Denmark)

    Vigeholm, B.; Kjøller, John; Larsen, Bent

    1980-01-01

    The reaction of hydrogen with commercially pure magnesium powder (above 99.7%) was investigated in the temperature range 250–400 °C. Hydrogen is readily sorbed above the dissociation pressure. During the initial exposure the magnesium powder sorbs hydrogen slowly below 400 °C but during the second...

  17. Energy investigations on the mechanical properties of magnesium alloyed by X = C, B, N, O and vacancy

    KAUST Repository

    Wu, Xiaozhi

    2013-10-25

    The generalized stacking fault (GSF) energies and surface energies of magnesium and its alloys with alloying atoms X = C, B, N, O and vacancy have been investigated using the first-principles methods. It is found that the predominant reducing effects of the alloying atoms and vacancy on the stacking fault energy are resulted from the position of them in the 1st layer near the slip plane. The stacking fault energies are nearly the same as the pure magnesium while the alloying atoms and vacancy are placed in the 2nd, 3rd, 4th, 5th and 6th layers. It has been shown that O strongly reduces the GSF energy of Mg. The alloying atoms C, B and N increase the surface energy, but O and vacancy reduce the surface energy of Mg. The ductilities of Mg and Mg alloys have been discussed based on the Rice criterion by using the ratio between surface energy and unstable stacking fault energy. © 2013 Higher Education Press and Springer-Verlag Berlin Heidelberg.

  18. Investigation of rare earth sealing of porous micro-arc oxidation coating formed on AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    M.Laleh; Farzad Kargar; A.Sabour Rouhaghdam

    2012-01-01

    Magnesium and its alloys have been used in many industries,but they are reactive and require protection against aggressive environments.In this study,oxide coatings were applied on AZ91D magnesium alloy using micro-arc oxidation (MAO) process.Then,in order to seal the pores of the MAO coatings,the samples were immersed in cerium bath for different times.The surface morphologies and compositions of the coatings were analyzed by scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS),respectively.The corrosion behavior of the coatings was investigated with electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in 3.5 wt.% NaCl solution.The amount of the porosity of the coating was measured by electrochemical method.It was found that the sealing treatments by immersion in cerium bath successfully sealed the pores of the MAO coatings.The results of the corrosion tests showed that the MAO coating which was sealed in Ce bath for 10 min enhanced the corrosion resistance of the substrate significantly.Furthermore,this coating had the lowest amount of the porosity among the coatings.

  19. Magnesium Hydroxide

    Science.gov (United States)

    Magnesium hydroxide is used on a short-term basis to treat constipation.This medication is sometimes prescribed ... Magnesium hydroxide come as a tablet and liquid to take by mouth. It usually is taken as ...

  20. Magnesium Test

    Science.gov (United States)

    ... be limited. Home Visit Global Sites Search Help? Magnesium Share this page: Was this page helpful? Also known as: Mg; Mag Formal name: Magnesium Related tests: Calcium , Potassium , Phosphorus , PTH , Vitamin D ...

  1. Dehydrogenation kinetics of pure and nickel-doped magnesium hydride investigated by in situ time-resolved powder X-ray diffraction

    DEFF Research Database (Denmark)

    Jensen, T.R.; Andreasen, A.; Vegge, Tejs;

    2006-01-01

    The dehydrogenation kinetics of pure and nickel (Ni)-doped (2w/w%) magnesium hydride (MgH2) have been investigated by in situ time-resolved powder X-ray diffraction (PXD). Deactivated samples, i.e. air exposed, are investigated in order to focus on the effect of magnesium oxide (MgO) surface layers...... conditions. A quartz capillary cell allowed the in situ study of gas/solid reactions. Three phases were identified: Mg, MgH2 and MgO and their phase fractions were extracted by Rietveld refinement or integration of selected reflections from each phase. Dehydrogenation curves were constructed and analysed by...... the Johnson-Mehi-Avrami formalism in order to derive rate constants at different temperatures. The apparent activation energies for dehydrogenation of pure and Ni-doped magnesium hydride were E-A approximate to 300 and 250 kJ/mol, respectively. Differential scanning calorimetry gave, E-A = 270 k...

  2. Investigation of minimum creep rates and stress exponents calculated from tensile and compressive creep data of magnesium alloy AE42

    International Nuclear Information System (INIS)

    Creep specimens prepared of magnesium alloy AE42 were investigated under constant load in compressive and in tensile creep. Material was cast via the squeeze casting process in order to obtain a dense microstructure without pores. Creep tests were performed at constant temperatures between 150 deg. C and 240 deg. C and constant applied stresses between 40 MPa and 120 MPa until a minimum creep rate was reached. It could be seen that the minimum creep rates in compressive creep tests were smaller than in tensile creep tests, and the difference increased with increasing applied stress. Stress exponents were determined according to the Norton equation and it was found that a threshold stress had to be introduced into the analysis. The threshold stress is based on strengthening by aluminum-rare earths precipitates. Calculating the true stress exponent, deformation mechanisms during creep could be clarified.

  3. Investigation of minimum creep rates and stress exponents calculated from tensile and compressive creep data of magnesium alloy AE42

    Energy Technology Data Exchange (ETDEWEB)

    Dieringa, Hajo, E-mail: hajo.dieringa@gkss.de [GKSS Research Centre, MagIC - Magnesium Innovation Centre, Max-Planck-Str. 1, 21502 Geesthacht (Germany); Hort, Norbert; Kainer, Karl Ulrich [GKSS Research Centre, MagIC - Magnesium Innovation Centre, Max-Planck-Str. 1, 21502 Geesthacht (Germany)

    2009-06-15

    Creep specimens prepared of magnesium alloy AE42 were investigated under constant load in compressive and in tensile creep. Material was cast via the squeeze casting process in order to obtain a dense microstructure without pores. Creep tests were performed at constant temperatures between 150 deg. C and 240 deg. C and constant applied stresses between 40 MPa and 120 MPa until a minimum creep rate was reached. It could be seen that the minimum creep rates in compressive creep tests were smaller than in tensile creep tests, and the difference increased with increasing applied stress. Stress exponents were determined according to the Norton equation and it was found that a threshold stress had to be introduced into the analysis. The threshold stress is based on strengthening by aluminum-rare earths precipitates. Calculating the true stress exponent, deformation mechanisms during creep could be clarified.

  4. An investigation into the microstructure/strain pattern relationship in backward extruded AZ91 magnesium alloy

    International Nuclear Information System (INIS)

    Highlights: ► Strain pattern developed during BE is inhomogeneous throughout the cross section. ► Microstructure evolution of AZ91 alloy was studied during BE at high temperatures. ► Heterogeneous microstructure fits well by related strain pattern over the cross section. ► Size and morphology of the γ-eutectic phase have been changed after BE processing. - Abstract: The contours of equivalent plastic strain (EPS) and shear strain (SS) over the cross section of backward extruded AZ91 magnesium alloy have been modeled employing the finite element method (FEM). The results indicate that the distributions of EPS and SS are not homogenous at different regions over the products’ cross section. In addition, the microstructure evolutions and strain pattern relationship have been explored through applying the backward extrusion (BE) method in the temperature range of 250–450 °C. The results indicate that the microstructural features (grain size, mechanical twins and γ-second phases) of different regions are strongly affected by applying backward extrusion, which is fairly consistent with the heterogeneous strain distribution. The obtained results are properly addressed relying on the principal deformation and restoration mechanisms, which operate under specified deformation conditions. The hardness measurements have been also employed to trace the related changes

  5. Theoretical investigation on the interaction between beryllium, magnesium and calcium with benzene, coronene, cirumcoronene and graphene

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The binding energies between benzene and Be, Mg and Ca are 1.8, 2.3 and 3.2 kcal/mol. • The alkaline earth complexes with benzene favor the non ionic configuration. • For these complexes charge transfer does not take place. • The performance of the DFT functionals assayed was poor. - Abstract: The interaction energies (IE) between benzene and beryllium, magnesium and calcium were calculated at the CCSD(T)/CBS level and including corrections for core-valence and relativistic effects. The IE are 1.8, 2.3 and 3.2 kcal/mol for Be, Mg and Ca, respectively, In contrast with our previous findings for the benzene–Li complex, we found that the non-ionic structure is more stable than the ionic configuration. Thus, charge-transfer from alkaline earths to benzene would not take place. The performance of MP2 and DFT functionals is poor. At the complete basis set limit, M06-2X, M06-L, B97D and MP2 exhibited similar MAD (∼ 0.7–0.8 kcal/mol). When larger aromatic models were considered, the IE were similar to those computed for benzene. Finally, taking into account the drawbacks of the DFT functionals, the computed IE for the non-ionic adsorption of Be, Mg and Ca onto graphene, are tentatively estimated as 2.1, 2.7 and 2.9 kcal/mol, respectively

  6. Can aluminium or magnesium be a surrogate for beryllium: A critical investigation of their chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Marot, Laurent, E-mail: laurent.marot@unibas.ch [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Linsmeier, Christian [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstraße 2, 85748 Garching b. München (Germany); Eren, Baran; Moser, Lucas; Steiner, Roland; Meyer, Ernst [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

    2013-10-15

    Highlights: • Review of the chemical and physical properties of Al, Mg and Be. • Similarity of Be and Al oxide. • Mg is not a good replacement for Be. -- Abstract: The use of beryllium is still an existing question according to the studies concerning the plasma–wall interactions which are expected to occur in ITER. Prediction of erosion and co-deposition processes for ITER is necessary for the design and the material choice of the first wall. In the current configuration, it is expected that co-deposited layers containing Be, tungsten and possibly carbon will be formed. However, the toxicity of Be limits its use in many experimental facilities around the world. Using aluminium or magnesium as Be replacements in laboratory experiments would solve this problem of toxicity and handling of Be mixed materials. A critical question which automatically arises is the relevance to use Al or Mg regarding the physical and chemical properties of both elements in comparison to the co-deposited layers expected in ITER. This work provides a review of the chemical and physical properties of Al and Mg, in the respect of comparing these properties to those of Be. Thanks to the similarity of its electronegativity to Be, Al can successfully resemble Be in terms of formation of compounds, especially the oxides and possibly the hydrides. However, due to the difference in the nature of the bonding, Mg cannot be a replacement for a possible hydride deposit formation.

  7. Investigation of Microstructure and Mechanical Properties of ECAP-Processed AM Series Magnesium Alloy

    Science.gov (United States)

    Gopi, K. R.; Nayaka, H. Shivananda; Sahu, Sandeep

    2016-07-01

    Magnesium alloy Mg-Al-Mn (AM70) was processed by equal channel angular pressing (ECAP) at 275 °C for up to 4 passes in order to produce ultrafine-grained microstructure and improve its mechanical properties. ECAP-processed samples were characterized for microstructural analysis using optical microscopy, scanning electron microscopy, and transmission electron microscopy. Microstructural analysis showed that, with an increase in the number of ECAP passes, grains refined and grain size reduced from an average of 45 to 1 µm. Electron backscatter diffraction analysis showed the transition from low angle grain boundaries to high angle grain boundaries in ECAP 4 pass sample as compared to as-cast sample. The strength and hardness values an showed increasing trend for the initial 2 passes of ECAP processing and then started decreasing with further increase in the number of ECAP passes, even though the grain size continued to decrease in all the successive ECAP passes. However, the strength and hardness values still remained quite high when compared to the initial condition. This behavior was found to be correlated with texture modification in the material as a result of ECAP processing.

  8. Can aluminium or magnesium be a surrogate for beryllium: A critical investigation of their chemistry

    International Nuclear Information System (INIS)

    Highlights: • Review of the chemical and physical properties of Al, Mg and Be. • Similarity of Be and Al oxide. • Mg is not a good replacement for Be. -- Abstract: The use of beryllium is still an existing question according to the studies concerning the plasma–wall interactions which are expected to occur in ITER. Prediction of erosion and co-deposition processes for ITER is necessary for the design and the material choice of the first wall. In the current configuration, it is expected that co-deposited layers containing Be, tungsten and possibly carbon will be formed. However, the toxicity of Be limits its use in many experimental facilities around the world. Using aluminium or magnesium as Be replacements in laboratory experiments would solve this problem of toxicity and handling of Be mixed materials. A critical question which automatically arises is the relevance to use Al or Mg regarding the physical and chemical properties of both elements in comparison to the co-deposited layers expected in ITER. This work provides a review of the chemical and physical properties of Al and Mg, in the respect of comparing these properties to those of Be. Thanks to the similarity of its electronegativity to Be, Al can successfully resemble Be in terms of formation of compounds, especially the oxides and possibly the hydrides. However, due to the difference in the nature of the bonding, Mg cannot be a replacement for a possible hydride deposit formation

  9. Investigation of Carboxylic Acid-Neodymium Conversion Films on Magnesium Alloy

    Science.gov (United States)

    Cui, Xiufang; Liu, Zhe; Lin, Lili; Jin, Guo; Wang, Haidou; Xu, Binshi

    2015-01-01

    The new carboxylic acid-neodymium anhydrous conversion films were successfully prepared and applied on the AZ91D magnesium alloy surface by taking absolute ethyl alcohol as solvent and four kinds of soluble carboxylic acid as activators. The corrosion resistance of the coating was measured by potentiodynamic polarization test in 3.5 wt.% NaCl solution in pH 7.0. The morphology, structure, and constituents of the coating were observed by scanning electron microscope, energy dispersivespectrum, x-ray photoelectron spectrum, and Fourier infrared spectrometer. Results show that corrosion resistance properties of samples coated with four different anhydrous conversion films were improved obviously. The corrosion potential increased, corrosion current density decreased, and polarization resistance increased. Among these four kinds of conversion films the one added with phytic exhibits the best corrosion resistant property. The mechanism of anhydrous-neodymium conversion film formation is also analyzed in this paper. It reveals that the gadolinium conversion coating is mainly composed of stable Nd2O3, MgO, Mg(OH)2, and carboxylate of Nd. And that the sample surface is rich in organic functional groups.

  10. Degradation and biological properties of Ca-P contained micro-arc oxidation self-sealing coating on pure magnesium for bone fixation

    OpenAIRE

    Wang, Weidan; Wan, Peng; Liu, Chen; Tan, Lili; Li, Weirong; Li, Lugee; Yang, Ke

    2014-01-01

    Poor corrosion resistance is one of the main disadvantages for biodegradable magnesium-based metals, especially applied for bone fixation, where there is a high demand of bio-mechanical strength and stability. Surface coating has been proved as an effective method to control the in vivo degradation. In this study a Ca-P self-sealing micro-arc oxidation (MAO) coating was studied to verify its efficacy and biological properties by in vitro and in vivo tests. It was found that the MAO coating co...

  11. Investigation of magnesium isotope fractionation during basalt differentiation: Implications for a chondritic composition of the terrestrial mantle

    Science.gov (United States)

    Teng, F.-Z.; Wadhwa, M.; Helz, R.T.

    2007-01-01

    To investigate whether magnesium isotopes are fractionated during basalt differentiation, we have performed high-precision Mg isotopic analyses by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) on a set of well-characterized samples from Kilauea Iki lava lake, Hawaii, USA. Samples from the Kilauea Iki lava lake, produced by closed-system crystal-melt fractionation, range from olivine-rich cumulates to highly differentiated basalts with MgO content ranging from 2.37 to 26.87??wt.%. Our results demonstrate that although these basalts have diverse chemical compositions, mineralogies, crystallization temperatures and degrees of differentiation, their Mg isotopic compositions display no measurable variation within the limits of our external precision (average ??26Mg = - 0.36 ?? 0.10 and ??25Mg = - 0.20 ?? 0.07; uncertainties are 2SD). This indicates that Mg isotopic fractionation during crystal-melt fractionation at temperatures of ??? 1055????C is undetectable at the level of precision of the current investigation. Calculations based on our data suggest that at near-magmatic temperatures the maximum fractionation in the 26Mg/24Mg ratio between olivine and melt is 0.07???. Two additional oceanic basalts, two continental basalts (BCR-1 and BCR-2), and two primitive carbonaceous chondrites (Allende and Murchison) analyzed in this study have Mg isotopic compositions similar to the Kilauea Iki lava lake samples. In contrast to a recent report [U. Wiechert, A.N. Halliday, Non-chondritic magnesium and the origins of the inner terrestrial planets, Earth and Planetary Science Letters 256 (2007) 360-371], the results presented here suggest that the Bulk Silicate Earth has a chondritic Mg isotopic composition. ?? 2007.

  12. Magnesium Cermets and Magnesium-Beryllium Alloys

    International Nuclear Information System (INIS)

    The paper describes some results of work on the development of magnesium-magnesium oxide cermets and of super heat-resistant magnesiumberyllium alloys produced by powder metallurgical methods. The introduction of even a minute quantity of finely dispersed magnesium oxide into magnesium results in a strengthening of the material, the degree of which increases with increased magnesium oxide concentration, although variation of this concentration within the limits of 0.3 to 5 wt.% has a comparatively slight effect on the corresponding variation in the short-term strength over the whole range of temperatures investigated. At 20oC, in the case of the cermets, σβ = 28 to 31 kg/mm2 and δ = 3 .5 to 4.5%; at 500oC σβ = 2.6 to 3.2 kg/mm2 and δ =30 to 40%. The positive effect of the finely dispersed oxide phase is particularly evident in protracted tests. For magnesium cermets, σ (300)/100 = 2.2 kg/mm2. Characteristic of the mixtures is the high thermal stability of the strength properties, linked chiefly with the thermodynamic stability of the strength-giving oxide phase in the metal matrix. The use of powder metallurgical methods has yielded super heat-resistant magnesium-beryllium alloys containing heightened concentrations of beryllium (PMB alloys). In their strength characteristics PMB alloys are close to Mg-MgO cermets, but the magnesium-beryllium alloys have a degree and duration of resistance to high temperature oxidation which exceeds the corresponding qualities of the magnesium alloys at present known. Thus, in air of 580oC, PMB alloys with 2 to 5% beryllium maintain a high resistance to oxidation for a period of over 12000 to 14000 h. This long-term heat resistance is chiefly a result of the amount of beryllium in the alloy, and increases with increasing beryllium content. PMB alloys are also marked by high resistance to short bursts of overheating. Magnesium cermets and magnesium-beryllium alloys, with their enhanced high-temperature stability, are capable

  13. Investigation on magnesium degradation under flow versus static conditions using a novel impedance-driven flow apparatus

    Institute of Scientific and Technical Information of China (English)

    Elbert David Mai; Huinan Liu

    2014-01-01

    This article reports a novel impedance-driven flow apparatus and its applicability for studying magnesium degradation under flow versus static conditions. Magnesium has potential to be an effective biomaterial for use inside the human body due to its biodegradability and biocompatibility. Magnesium undergoes degradation reactions in aqueous solutions such as body fluids, leading to mass loss and pH increase of the surrounding fluid. To compare the degradation process of magnesium under flow versus static conditions, a novel flow apparatus consisting of an impedance pump and a flow chamber was designed and constructed. In addition to low-cost, this apparatus is flexible to be sterilized and assembled, and is small enough for use inside an incubator, making it appealing for measuring and comparing magnesium degradation in vitro under flow versus static conditions. The average flow rate in this flow apparatus was 2.8 ml/s, mimicking the flow rate (2.6 ml/s) in coronary artery. In a simulated body fluid (SBF), magnesium samples lost their mass at a much faster rate under the flow condition than that under the static condition. Starting with a pH of 7.4, the SBF showed a pH increase to 8.5 under the flow condition within 96 h due to the degradation of magnesium, greater than the pH increase under the static condition. The results of this study demonstrated the effects of fluid flow on magnesium degradation using the impedance-driven flow apparatus, providing useful design guidelines for magnesium-based implants that may be exposed to body fluid flow.

  14. Ion-molecule interactions of biological importance. A vibrational spectroscopic study of magnesium complexes with hydroxylated quinones

    International Nuclear Information System (INIS)

    Luteoskyrin and rugulosin are two naturally occurring yellow pigments with hydroxylated bis-anthraquinonic structures. They cause serious liver disorders in man due to the formation of complexes of the type pigment-Mg2+-DNA. In order to elucidate the structure of these complexes we have studied the vibrational spectra of some model systems, namely 1-hydroxy- and 1,4-dihydroxyanthraquinone, their magnesium chelate complexes, and a series of simpler complexes as the acetylacetonates of some divalent metals. Complete vibrational assignment are proposed for anthraquinone-9,10, the two hydroxylated and deureroxylated derivatives and their magnesium complexes. The substitution of 26Mg in place of 24Mg in these complexes enabled us to assign the Mg-O vibrations; their number corresponds to a hexa-coordinated metal in the acetylacetonate case and to a tetra-coordinated structure in the anthraquinone-olates complexes. The position of the ν C=0 and ν C-0 vibrations bands in the complexes shows that the bonds in the chelated ring of Mg(1-O-AQ)2 retains their single and double bond characteristic whereas in the CMg(1,4-O2,-AQ)n a resonating structure appears in the ring. The study of the IR and R spectra of the complexes enabled a tetrahedral structure to be proposed for the oxygens around the magnesium. Finally it was noted that the Mg-O bonds possessed a high degree of covalent character. (author)

  15. Investigations of biological processes in Austrian MBT plants

    International Nuclear Information System (INIS)

    Mechanical biological treatment (MBT) of municipal solid waste (MSW) has become an important technology in waste management during the last decade. The paper compiles investigations of mechanical biological processes in Austrian MBT plants. Samples from all plants representing different stages of degradation were included in this study. The range of the relevant parameters characterizing the materials and their behavior, e.g. total organic carbon, total nitrogen, respiration activity and gas generation sum, was determined. The evolution of total carbon and nitrogen containing compounds was compared and related to process operation. The respiration activity decreases in most of the plants by about 90% of the initial values whereas the ammonium release is still ongoing at the end of the biological treatment. If the biogenic waste fraction is not separated, it favors humification in MBT materials that is not observed to such extent in MSW. The amount of organic carbon is about 15% dry matter at the end of the biological treatment.

  16. Investigations of biological processes in Austrian MBT plants.

    Science.gov (United States)

    Tintner, J; Smidt, E; Böhm, K; Binner, E

    2010-10-01

    Mechanical biological treatment (MBT) of municipal solid waste (MSW) has become an important technology in waste management during the last decade. The paper compiles investigations of mechanical biological processes in Austrian MBT plants. Samples from all plants representing different stages of degradation were included in this study. The range of the relevant parameters characterizing the materials and their behavior, e.g. total organic carbon, total nitrogen, respiration activity and gas generation sum, was determined. The evolution of total carbon and nitrogen containing compounds was compared and related to process operation. The respiration activity decreases in most of the plants by about 90% of the initial values whereas the ammonium release is still ongoing at the end of the biological treatment. If the biogenic waste fraction is not separated, it favors humification in MBT materials that is not observed to such extent in MSW. The amount of organic carbon is about 15% dry matter at the end of the biological treatment. PMID:20580543

  17. Magnesium as Biodegradable Implant Material

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Drawbacks associated with permanent metallic implants lead to the search for degradable metallic biomaterials. Magnesium alloys have been highly considered as Mg has a high biocorrosion potential and is essential to bodies. In this study, corrosion behaviour of pure magnesium and magnesium alloy AZ31 in both static and dynamic physiological conditions (Hank's solution) has been investigated. It is found that the materials degrade fast at beginning, then stabilize after 5 days of immersion. High purity in th...

  18. Beyond the Biology: A Systematic Investigation of Noncontent Instructor Talk in an Introductory Biology Course

    OpenAIRE

    Seidel, Shannon B.; Reggi, Amanda L.; Schinske, Jeffrey N.; Burrus, Laura W.; Tanner, Kimberly D.

    2015-01-01

    Instructors create classroom environments that have the potential to impact learning by affecting student motivation, resistance, and self-efficacy. However, despite the critical importance of the learning environment in increasing conceptual understanding, little research has investigated what instructors say and do to create learning environments in college biology classrooms. We systematically investigated the language used by instructors that does not directly relate to course content and...

  19. Production of magnesium metal

    Science.gov (United States)

    Blencoe, James G [Harriman, TN; Anovitz, Lawrence M [Knoxville, TN; Palmer, Donald A [Oliver Springs, TN; Beard, James S [Martinsville, VA

    2010-02-23

    A process of producing magnesium metal includes providing magnesium carbonate, and reacting the magnesium carbonate to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The carbon dioxide is used as a reactant in a second process. In another embodiment of the process, a magnesium silicate is reacted with a caustic material to produce magnesium hydroxide. The magnesium hydroxide is reacted with a source of carbon dioxide to produce magnesium carbonate. The magnesium carbonate is reacted to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The invention further relates to a process for production of magnesium metal or a magnesium compound where an external source of carbon dioxide is not used in any of the reactions of the process. The invention also relates to the magnesium metal produced by the processes described herein.

  20. Investigation of possibility of magnesium-mineral composition production on the base of dolomite for immobilization of radioactive waste

    International Nuclear Information System (INIS)

    Process features of producing of magnesium astringent substances on the base of magnesite and dolomite and their characteristic arc examined. The potential possibility of creation of compositional material based on caustic dolomite, that was obtained from natural dolomite raw materials of Belarus, for immobilization of radioactive waste is presented. (authors).

  1. A shell-model investigation of the binding energies of some exotic isotopes of sodium and magnesium

    International Nuclear Information System (INIS)

    Standard shell-model calculations of the binding energies of the neutron-rich isotopes of sodium and magnesium are in strong disagreement with the experimental values near N=20. It is shown that the discrepancy can be explained by allowing neutron excitations from the dsub(3/2) shell into the fsub(7/2) shell. (author)

  2. 76 FR 69284 - Pure Magnesium From China

    Science.gov (United States)

    2011-11-08

    ... COMMISSION Pure Magnesium From China Determination On the basis of the record \\1\\ developed in the subject... order on pure magnesium from China would be likely to lead to continuation or recurrence of material... USITC Publication 4274 (October 2011), entitled Pure Magnesium from China: Investigation No....

  3. Investigations of superparamagnetism in magnesium ferrite nano-sphere synthesized by ultrasonic spray pyrolysis technique for hyperthermia application

    International Nuclear Information System (INIS)

    In this paper, we present the synthesized of magnesium ferrite (MgFe2O4) nano-spheres by a single-step ultrasonic spray pyrolysis (USP) technique from the aqueous metal nitrate precursor solution without any organic additives or post-annealing processes. The effects of different pyrolysis temperatures on the particles size, morphology and their superparamagnetic behavior have been investigated to evaluate the heat generation efficiency in an AC magnetic field. The X-ray powder diffraction spectra of MgFe2O4 nano-spheres synthesized at the pyrolysis temperatures of 600, 700, 800 and 900 °C exhibited single phase cubic structure and obtained mean crystallite size (primary particles) of 4.05, 9.6, 15.97 and 31.48 nm, respectively. Transmission electron microscopy (TEM) confirms that the particles consisted of aggregates of the primary crystallite had densely congested spherical morphology with extremely smooth surface appearance. Field emission electron microscopy (FESEM) reveals that the shape and size of the nano-spheres (secondary particles) does not change significantly but the degree of agglomeration between the secondary particles was reduced with increasing the pyrolysis temperature. The average size and size distribution of nano-spheres measured using electrophoretic scattering photometer have found very low polydispersity index (PDI) for all samples. The field dependent magnetization studies indicated superparamagnetic nature for the particles having crystallite size i.e. 4.05 and 9.6 nm and exhibited ferromagnetic nature for 15.97 and 31.48 nm. It is also demonstrated that, as the pyrolysis temperature increases, the saturation magnetization of the MgFe2O4 nanopowders increases due to enhancement of crystallites. The shift in Curie temperature is well described by the finite-size scaling formula. The magnetically loss heating values of selected samples in crystallite size of 9.6 and 15.97 nm were investigated by measuring the time dependent temperature

  4. Investigations of superparamagnetism in magnesium ferrite nano-sphere synthesized by ultrasonic spray pyrolysis technique for hyperthermia application

    Science.gov (United States)

    Das, Harinarayan; Sakamoto, Naonori; Aono, Hiromichi; Shinozaki, Kazuo; Suzuki, Hisao; Wakiya, Naoki

    2015-10-01

    In this paper, we present the synthesized of magnesium ferrite (MgFe2O4) nano-spheres by a single-step ultrasonic spray pyrolysis (USP) technique from the aqueous metal nitrate precursor solution without any organic additives or post-annealing processes. The effects of different pyrolysis temperatures on the particles size, morphology and their superparamagnetic behavior have been investigated to evaluate the heat generation efficiency in an AC magnetic field. The X-ray powder diffraction spectra of MgFe2O4 nano-spheres synthesized at the pyrolysis temperatures of 600, 700, 800 and 900 °C exhibited single phase cubic structure and obtained mean crystallite size (primary particles) of 4.05, 9.6, 15.97 and 31.48 nm, respectively. Transmission electron microscopy (TEM) confirms that the particles consisted of aggregates of the primary crystallite had densely congested spherical morphology with extremely smooth surface appearance. Field emission electron microscopy (FESEM) reveals that the shape and size of the nano-spheres (secondary particles) does not change significantly but the degree of agglomeration between the secondary particles was reduced with increasing the pyrolysis temperature. The average size and size distribution of nano-spheres measured using electrophoretic scattering photometer have found very low polydispersity index (PDI) for all samples. The field dependent magnetization studies indicated superparamagnetic nature for the particles having crystallite size i.e. 4.05 and 9.6 nm and exhibited ferromagnetic nature for 15.97 and 31.48 nm. It is also demonstrated that, as the pyrolysis temperature increases, the saturation magnetization of the MgFe2O4 nanopowders increases due to enhancement of crystallites. The shift in Curie temperature is well described by the finite-size scaling formula. The magnetically loss heating values of selected samples in crystallite size of 9.6 and 15.97 nm were investigated by measuring the time dependent temperature

  5. [Investigation of the microstructure of biological systems by triplet label].

    Science.gov (United States)

    Kotel'niko, A I; Kuznetsov, S N; Fogel', V R; Likhtenshteĭn, G I

    1979-01-01

    A method for investigating the microstruct and dynamics of biological systems by means of triplet-excited molecules is suggested. The method is based on the phenomenon of triplet excitation disactivation by exchange-resonance triplet-triplet energy transfer to the acceptor or by intercombination conversion induced by interaction of an excited molecule with a paramagnetic center. The disactivation efficiency was measured by registrating the phosphorescense decay kinetics. The interaction of the triplet label eosin isothiocyanate, covalently coupled with albumine, lysozyme, sarcoplasmic reticulum membrane and Ca-Mg-dependent sarcoplasmic reticulum ATPase, with O2, the stable nitroxide radicals and ions of Mn2+ was investigated to analyse the potentialities of this method. As a model system the eosin phosphorescence quenching by the same quenchers in glycerine-aguaous solutions was studied. The method permits to investigate the microviscosity and microstructure of biological objects in the label attached region on interaction of the label with a sound-quencher with constants being 10(4) divided by 10(9) M-1 sec-1 and to measure the lateral diffusion of molecules in highly viscosity media (10 divided by 10(5) santypuas). PMID:223037

  6. Marine Biological Investigations at the Eniwetok Test Site

    International Nuclear Information System (INIS)

    The results of marine biological investigations conducted at the Eniwetok Test Site since 1952 are summarized. Radioisotopes introduced into the sea from the tests at various times since then include fission products and other radioisotopes (U237, Np239, Mn54, Fe55,59, Co57,58,60, Zn65 and W185). The levels of radioisotopes in plankton samples taken 4 days to 6 weeks after contamination are reported and the distribution of the radioactivity between plankton and water is given. Grazing fishes contained Zn65, Fe55, Co57,58,60 and Mn54. Carnivorous fishes contained mostly Fe55 and Zn65. (author)

  7. Biodegradable magnesium nanoparticle-enhanced laser hyperthermia therapy

    Directory of Open Access Journals (Sweden)

    Wang Q

    2012-08-01

    Full Text Available Qian Wang,1 Liping Xie,1 Zhizhu He,2 Derui Di,2 Jing Liu1,21Department of Biomedical Engineering, School of Medicine, Tsinghua University, 2Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, People's Republic of ChinaBackground: Recently, nanoparticles have been demonstrated to have tremendous merit in terms of improving the treatment specificity and thermal ablation effect on tumors. However, the potential toxicity and long-term side effects caused by the introduced nanoparticles and by expelling them out of the body following surgery remain a significant challenge. Here, we propose for the first time to directly adopt magnesium nanoparticles as the heating enhancer in laser thermal ablation to avoid these problems by making full use of the perfect biodegradable properties of this specific material.Methods: To better understand the new nano “green” hyperthermia modality, we evaluated the effects of magnesium nanoparticles on the temperature transients inside the human body subject to laser interstitial heating. Further, we experimentally investigated the heating enhancement effects of magnesium nanoparticles on a group of biological samples: oil, egg white, egg yolk, in vitro pig tissues, and the in vivo hind leg of rabbit when subjected to laser irradiation.Results: Both the theoretical simulations and experimental measurements demonstrated that the target tissues injected with magnesium nanoparticles reached much higher temperatures than tissues without magnesium nanoparticles. This revealed the enhancing behavior of the new nanohyperthermia method.Conclusion: Given the unique features of magnesium nanoparticles – their complete biological safety and ability to enhance heating – which most other advanced metal nanoparticles do not possess, the use of magnesium nanoparticles in hyperthermia therapy offers an important “green” nanomedicine modality for treating tumors

  8. Magnesium substitution in the structure of orthopedic nanoparticles: A comparison between amorphous magnesium phosphates, calcium magnesium phosphates, and hydroxyapatites

    International Nuclear Information System (INIS)

    As biocompatible materials, magnesium phosphates have received a lot of attention for orthopedic applications. During the last decade multiple studies have shown advantages for magnesium phosphate such as lack of cytotoxicity, biocompatibility, strong mechanical properties, and high biodegradability. The present study investigates the role of Mg+2 and Ca+2 ions in the structure of magnesium phosphate and calcium phosphate nanoparticles. To directly compare the effect of Mg+2 and Ca+2 ions on structure of nanoparticles and their biological behavior, three groups of nanoparticles including amorphous magnesium phosphates (AMPs) which release Mg+2, calcium magnesium phosphates (CMPs) which release Mg+2 and Ca+2, and hydroxyapatites (HAs) which release Ca+2 were studied. SEM, TEM, XRD, and FTIR were used to evaluate the morphology, crystallinity, and chemical properties of the particles. AMP particles were homogeneous nanospheres, whereas CMPs were combinations of heterogeneous nanorods and nanospheres, and HAs which contained heterogeneous nanosphere particles. Cell compatibility was monitored in all groups to determine the cytotoxicity effect of particles on studied MC3T3-E1 preosteoblasts. AMPs showed significantly higher attachment rate than the HAs after 1 day and both AMPs and CMPs showed significantly higher proliferation rate when compared to HAs after 7 days. Gene expression level of osteoblastic markers ALP, COL I, OCN, OPN, RUNX2 were monitored and they were normalized to GAPDH housekeeping gene. Beta actin expression level was monitored as the second housekeeping gene to confirm the accuracy of results. In general, AMPs and CMPs showed higher expression level of osteoblastic genes after 7 days which can further confirm the stimulating role of Mg+2 and Ca+2 ions in increasing the proliferation rate, differentiation, and mineralization of MC3T3-E1 preosteoblasts. - Highlights: • Role of Mg2+ and Ca2+ ions in proliferation, and differentiation of

  9. Blood triggered corrosion of magnesium alloys

    International Nuclear Information System (INIS)

    Intravascular stents manufactured out of bioabsorbable magnesium (Mg) or Mg-alloys are considered as auspicious candidates for the next stent generation. However, before clinical application numerous physical and biological tests, especially to predict the clinically highly important degradation kinetics in vivo, have to be performed. In a Chandler-Loop model, the initial degradation of eight different magnesium alloys during 6 h in contact with human whole blood was investigated. The magnesium release varied between 0.91 ± 0.33 mg/cm2 (MgAl9Zn1) and 2.57 ± 0.38 mg/cm2 (MgZn1). No correlation could be found with Mg release data obtained after immersion in simulated body fluid (SBF). This pilot study showed that Mg corrosion is highly influenced by the biological test environment (SBF or blood, etc.) and that a modified Chandler-Loop model with human whole blood may be superior to predict corrosion of Mg alloys under clinical conditions than the SBF models presently used.

  10. Investigations of superparamagnetism in magnesium ferrite nano-sphere synthesized by ultrasonic spray pyrolysis technique for hyperthermia application

    Energy Technology Data Exchange (ETDEWEB)

    Das, Harinarayan, E-mail: hn_das@yahoo.com [Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku Naka-ku, Hamamatsu 432-8561 (Japan); Materials Science Division, Atomic Energy Centre, Bangladesh Atomic Energy Commission, Dhaka 1000, Bangladesh (Bangladesh); Sakamoto, Naonori [Department of Electronics and Materials Science, Shizuoka University, 3-5-1 Johoku Naka-ku, Hamamatsu 432-8561 (Japan); Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku Naka-ku, Hamamatsu 432-8561 (Japan); Aono, Hiromichi [Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790-85770 (Japan); Shinozaki, Kazuo [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1 O-okayama Meguro-ku, Tokyo 152-8550 (Japan); Suzuki, Hisao; Wakiya, Naoki [Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku Naka-ku, Hamamatsu 432-8561 (Japan); Department of Electronics and Materials Science, Shizuoka University, 3-5-1 Johoku Naka-ku, Hamamatsu 432-8561 (Japan); Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku Naka-ku, Hamamatsu 432-8561 (Japan)

    2015-10-15

    In this paper, we present the synthesized of magnesium ferrite (MgFe{sub 2}O{sub 4}) nano-spheres by a single-step ultrasonic spray pyrolysis (USP) technique from the aqueous metal nitrate precursor solution without any organic additives or post-annealing processes. The effects of different pyrolysis temperatures on the particles size, morphology and their superparamagnetic behavior have been investigated to evaluate the heat generation efficiency in an AC magnetic field. The X-ray powder diffraction spectra of MgFe{sub 2}O{sub 4} nano-spheres synthesized at the pyrolysis temperatures of 600, 700, 800 and 900 °C exhibited single phase cubic structure and obtained mean crystallite size (primary particles) of 4.05, 9.6, 15.97 and 31.48 nm, respectively. Transmission electron microscopy (TEM) confirms that the particles consisted of aggregates of the primary crystallite had densely congested spherical morphology with extremely smooth surface appearance. Field emission electron microscopy (FESEM) reveals that the shape and size of the nano-spheres (secondary particles) does not change significantly but the degree of agglomeration between the secondary particles was reduced with increasing the pyrolysis temperature. The average size and size distribution of nano-spheres measured using electrophoretic scattering photometer have found very low polydispersity index (PDI) for all samples. The field dependent magnetization studies indicated superparamagnetic nature for the particles having crystallite size i.e. 4.05 and 9.6 nm and exhibited ferromagnetic nature for 15.97 and 31.48 nm. It is also demonstrated that, as the pyrolysis temperature increases, the saturation magnetization of the MgFe{sub 2}O{sub 4} nanopowders increases due to enhancement of crystallites. The shift in Curie temperature is well described by the finite-size scaling formula. The magnetically loss heating values of selected samples in crystallite size of 9.6 and 15.97 nm were investigated by measuring

  11. Beyond the Biology: A Systematic Investigation of Noncontent Instructor Talk in an Introductory Biology Course.

    Science.gov (United States)

    Seidel, Shannon B; Reggi, Amanda L; Schinske, Jeffrey N; Burrus, Laura W; Tanner, Kimberly D

    2015-01-01

    Instructors create classroom environments that have the potential to impact learning by affecting student motivation, resistance, and self-efficacy. However, despite the critical importance of the learning environment in increasing conceptual understanding, little research has investigated what instructors say and do to create learning environments in college biology classrooms. We systematically investigated the language used by instructors that does not directly relate to course content and defined the construct of Instructor Talk. Transcripts were generated from a semester-long, cotaught introductory biology course (n = 270 students). Transcripts were analyzed using a grounded theory approach to identify emergent categories of Instructor Talk. The five emergent categories from analysis of more than 600 quotes were, in order of prevalence, 1) Building the Instructor/Student Relationship, 2) Establishing Classroom Culture, 3) Explaining Pedagogical Choices, 4) Sharing Personal Experiences, and 5) Unmasking Science. Instances of Instructor Talk were present in every class session analyzed and ranged from six to 68 quotes per session. The Instructor Talk framework is a novel research variable that could yield insights into instructor effectiveness, origins of student resistance, and methods for overcoming stereotype threat. Additionally, it holds promise in professional development settings to assist instructors in reflecting on the learning environments they create. PMID:26582237

  12. Magnesium in Clinical Practice

    OpenAIRE

    E.L. Trisvetova

    1989-01-01

    Magnesium is a macronutrient that is needed for normal body functions. Magnesium deficiency resulting from the influence of exogenous and endogenous factors, is diagnosed by clinical manifestations, resembling the known disease. Magnesium deficiency corrected with the magnesium therapy. Studies show the effectiveness of magnesium orotate for many cardiovascular diseases.

  13. Investigating the Efficiency of Biological Filters for Ammonia Removal

    Directory of Open Access Journals (Sweden)

    S Motesaddi Zarandi, MR Massoudinejad, A Mazaheri Tehrani, H Pouri

    2013-09-01

    Full Text Available Backgrounds and Aims: Ammonia removal from air to prevent severe damage to the environment and living organisms is very important. Biofiltration is an efficient, easy, cost-effective, and environmentally friendly process for degradation of ammonia from waste air. The aim of this study is to investigate the efficiency of biological filtration using a compost and scallop bed for ammonia removal. Materials and Methods: According to the ammonia removal method a column with 14cm inner diameter and 45cm height made from transparent Plexiglas was used. The column was filled up to 25 cm with compost and scallop (with a scallop: compost ratio of 1:4. In this study, performance of the biofilter was studied under 10 different flow rates (1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 lit/min and 5 different concentrations (0-20, 20-40, 40-60, 60-80 and 80-100 ppm at a temperature of 25 degrees Celsius. Results: The results of this study showed that efficiency is decreased when the flow rate or concentration is increased because the microbial population is reduced. The efficiency was reduced by 84.6-98.2 percent. Maximum efficiency occurred at a 0.19g/(m3.h loading rate. Efficiency was in 0-20 concentration intervals at a flow rate of 1 lit/min and at an Empty Bed Residence Time (EBRT of 240 seconds. Conclusion: The results show that a biofilter with a compost and scallop bed is efficient for ammonia removal from air. Results can be optimized in the design and operation of biological systems to be used in the industrial control of ammonia gas.

  14. Magnesium compounds

    Science.gov (United States)

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  15. Magnesium in diet

    Science.gov (United States)

    Diet - magnesium ... Magnesium is needed for more than 300 biochemical reactions in the body. It helps to maintain normal ... There is ongoing research into the role of magnesium in preventing and managing disorders such as high ...

  16. Corrosion of magnesium alloy AZ31 screws is dependent on the implantation site

    Energy Technology Data Exchange (ETDEWEB)

    Willbold, E. [Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, D - 30625 Hannover (Germany); Kaya, A.A. [Mugla University, Engineering Faculty, Metallurgy and Materials Engineering Department, Mugla (Turkey); Kaya, R.A. [MedicalPark Hospital, Kueltuer Sok No:1, 34160 Bahcelievler, Istanbul (Turkey); Beckmann, F. [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Max-Planck-Str.1, D - 21502 Geesthacht (Germany); Witte, F., E-mail: witte.frank@mh-hannover.de [Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, D - 30625 Hannover (Germany)

    2011-12-15

    The corrosion of biodegradable materials is a crucial issue in implant development. Among other materials, magnesium and magnesium based alloys are one of the most promising candidates. Since the corrosion of biodegradable materials depends on different physiological parameters like pH or ion concentrations, the corrosion might be different in different biological environments. To investigate this issue, we produced screws from magnesium alloy AZ31 and implanted them into the hip bone of 14 sheep. After 3 and 6 months, the screws were explanted and analyzed with synchrotron-radiation based micro-computed tomography and hard tissue histology. We found considerable differences in the corrosion behavior of the magnesium screws with respect to its original tissue location. However, we could detect a normal immunological tissue response.

  17. Corrosion of magnesium alloy AZ31 screws is dependent on the implantation site

    International Nuclear Information System (INIS)

    The corrosion of biodegradable materials is a crucial issue in implant development. Among other materials, magnesium and magnesium based alloys are one of the most promising candidates. Since the corrosion of biodegradable materials depends on different physiological parameters like pH or ion concentrations, the corrosion might be different in different biological environments. To investigate this issue, we produced screws from magnesium alloy AZ31 and implanted them into the hip bone of 14 sheep. After 3 and 6 months, the screws were explanted and analyzed with synchrotron-radiation based micro-computed tomography and hard tissue histology. We found considerable differences in the corrosion behavior of the magnesium screws with respect to its original tissue location. However, we could detect a normal immunological tissue response.

  18. Investigating global change and fish biology with fish otolith radiocarbon

    Science.gov (United States)

    Kalish, John M.

    1994-06-01

    Fish otoliths, calcium carbonate gravity and auditory receptors in the membranous labyrinths of teleost fish, can provide radiocarbon data that are valuable to a wide range of disciplines. For example, the first pre- and post-bomb time series of radiocarbon levels from northern or southern hemisphere temperate oceans was obtained by carrying out accelerator mass spectrometry analyses on selected regions of fish otoliths. These data can provide powerful constraints on both carbon cycle models and ocean general circulation models. Because fish otoliths can serve as a proxy of radiocarbon in seawater dissolved inorganic carbon in all oceans and at most depths, there is considerable scope for further investigations of otolith radiocarbon in relation to both oceanography and global change. In addition to applications relevant to global change, fish otoliths are also valuable sources of information on the age, growth, and ecology of fishes, with age being among the most important parameters in population modelling and fisheries management. Use of the bomb radiocarbon chronometer to validate fish age determination methods offers considerable advantages over traditional forms of age validation and promises to become a standard tool in fish biology and fisheries management. Radiocarbon data from otoliths can also provide valuable information on the ecology of fishes and has already provided surprising information relevant to the ecology of some deep-sea fishes.

  19. An Investigation of the Biochemistry of Biological Phosphorus Removal

    OpenAIRE

    Erdal, Zeynep Kisoglu

    2002-01-01

    Although enhanced biological phosphorus removal (EBPR) and complete biological nutrient removal (BNR) systems can be operated successfully by experienced operators, the accuracy of design and strength of the scientific background need to be reinforced to enable accurate modeling and economically optimal design. One way to accomplish this would be through a better understanding of the biochemical mechanisms and microbial population dynamics that determine the reliability and efficiency of EBPR...

  20. Dehydrogenation kinetics for pure and nickel-doped magnesium hydride investigated by in-situ, time-resolved powder diffraction (poster)

    DEFF Research Database (Denmark)

    Jensen, T.R.; Andreasen, A.; Vegge, T.;

    2004-01-01

    The dehydrogenation kinetics of pure and nickel-doped magnesium hydride was investigated by in-situ, time-resolved X-ray powder diffraction. A special reaction cell allowed the study of gas/solid reactions and analysis of the exhaust gas by massspectroscopy. X-ray data (0 <2è <120°) was collected...... under isothermal conditions with a time resolution of 45 s. Three phases were identified, Mg,MgH2 and MgO, and the phase fractions were extracted for each phase. Dehydrogenation curves wereconstructed and analyzed by the Johnson-Mehl-Avrami formalism in order to derive rateconstants at different....... Furthermore, the difference in apparent activation energy of ca. 50 kJ/mol compares totheoretical calculations for the atomisation of H2 molecules, which might be the rate-determining step in the dehydrogenation process....

  1. Magnetic study of interatomic interactions, synthesis, structural and mass spectroscopy investigations of lanthanum gallate doped with cobalt and magnesium

    International Nuclear Information System (INIS)

    Highlights: • Single phase LaCoxGa1−1.2xMg0.2xO3 and LaCoxGa1−1.5xMg0.5xO3 solutions were obtained. • Two crystalline modifications of solid solutions were found by Rietveld method. • Ferromagnetic clusters including Co, Mg and accompanying oxygen vacancies are found. • Magnetic behavior of clusters is of superparamagnetic type. - Abstract: For the first time by X-ray method two phases of the solid solutions LaCoxGa1−1.2xMg0.2xO3−δ and LaCoxGa1−1.5xMg0.5xO3−δ (x = 0.01–0.10) with different structure were found – rhombohedral and orthorhombic phases. On the basis of the data on evaporation of the components a synthetic procedure was advanced allowing the losses of cobalt to be minimized. The study of magnetic characteristics of obtained solid solutions showed the formation of high nuclearity clusters containing cobalt atoms, and also magnesium and associated vacancies even in diluted solid solutions. Clusters are characterized by a competition between ferro- and antiferromagnetic exchange interactions, whereas the long order exchange is antiferromagnetic

  2. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    A K Misra; Renu Mathur

    2007-06-01

    The scope of magnesium oxychloride (MOC) cement in concrete works has been evaluated. MOC cement concrete compositions of varying strengths having good placing and finishing characteristics were prepared and investigated for their compressive and flexural strengths, -values, abrasion resistance etc. The durability of MOC concrete compositions against extreme environmental conditions viz. heating–cooling, freezing–thawing, wetting–drying and penetration and deposition of salts etc were investigated. The results reveal that MOC concrete has high compressive strength associated with high flexural strength and the ratio of compressive to flexural strength varies between 6 and 8. The elastic moduli of the compositions studied are found to be 23–85 GPa and the abrasion losses between 0.11 and 0.20%. While alternate heating–cooling cycles have no adverse effect on MOC concrete, it can be made durable against freezing–thawing and the excessive exposure to water and salt attack by replacing 10% magnesium chloride solution by magnesium sulphate solution of the same concentration.

  3. FIELD INVESTIGATION OF BIOLOGICAL TOILET SYSTEMS AND GREY WATER TREATMENT

    Science.gov (United States)

    The objective of the field program was to determine the operational characteristics and overall acceptability of popular models of biological toilets and a few select grey water systems. A field observation scheme was devised to take advantage of in-use sites throughout the State...

  4. Investigation of the potential for direct compaction of a fine ibuprofen powder dry-coated with magnesium stearate.

    Science.gov (United States)

    Qu, Li; Zhou, Qi Tony; Gengenbach, Thomas; Denman, John A; Stewart, Peter J; Hapgood, Karen P; Gamlen, Michael; Morton, David A V

    2015-05-01

    Intensive dry powder coating (mechanofusion) with tablet lubricants has previously been shown to give substantial powder flow improvement. This study explores whether the mechanofusion of magnesium stearate (MgSt), on a fine drug powder can substantially improve flow, without preventing the powder from being directly compacted into tablets. A fine ibuprofen powder, which is both cohesive and possesses a low-melting point, was dry coated via mechanofusion with between 0.1% and 5% (w/w) MgSt. Traditional low-shear blending was also employed as a comparison. No significant difference in particle size or shape was measured following mechanofusion. For the low-shear blended powders, only marginal improvement in flowability was obtained. However, after mechanofusion, substantial improvements in the flow properties were demonstrated. Both XPS and ToF-SIMS demonstrated high degrees of a nano-scale coating coverage of MgSt on the particle surfaces from optimized mechanofusion. The study showed that robust tablets were produced from the selected mechanofused powders, at high-dose concentration and tablet tensile strength was further optimized via addition of a Polyvinylpyrrolidone (PVP) binder (10% w/w). The tablets with the mechanofused powder (with or without PVP) also exhibited significantly lower ejection stress than those made of the raw powder, demonstrating good lubrication. Surprisingly, the release rate of drug from the tablets made with the mechanofused powder was not retarded. This is the first study to demonstrate such a single-step dry coating of model drug with MgSt, with promising flow improvement, flow-aid and lubrication effects, tabletability and also non-inhibited dissolution rate. PMID:24738790

  5. Influence of Magnesium Alloy Degradation on Undifferentiated Human Cells.

    Directory of Open Access Journals (Sweden)

    Francesca Cecchinato

    Full Text Available Magnesium alloys are of particular interest in medical science since they provide compatible mechanical properties with those of the cortical bone and, depending on the alloying elements, they have the capability to tailor the degradation rate in physiological conditions, providing alternative bioresorbable materials for bone applications. The present study investigates the in vitro short-term response of human undifferentiated cells on three magnesium alloys and high-purity magnesium (Mg.The degradation parameters of magnesium-silver (Mg2Ag, magnesium-gadolinium (Mg10Gd and magnesium-rare-earth (Mg4Y3RE alloys were analysed after 1, 2, and 3 days of incubation in cell culture medium under cell culture condition. Changes in cell viability and cell adhesion were evaluated by culturing human umbilical cord perivascular cells on corroded Mg materials to examine how the degradation influences the cellular development.The pH and osmolality of the medium increased with increasing degradation rate and it was found to be most pronounced for Mg4Y3RE alloy. The biological observations showed that HUCPV exhibited a more homogeneous cell growth on Mg alloys compared to high-purity Mg, where they showed a clustered morphology. Moreover, cells exhibited a slightly higher density on Mg2Ag and Mg10Gd in comparison to Mg4Y3RE, due to the lower alkalinisation and osmolality of the incubation medium. However, cells grown on Mg10Gd and Mg4Y3RE generated more developed and healthy cellular structures that allowed them to better adhere to the surface. This can be attributable to a more stable and homogeneous degradation of the outer surface with respect to the incubation time.

  6. Influence of Magnesium Alloy Degradation on Undifferentiated Human Cells

    Science.gov (United States)

    Martinez-Sanchez, Adela Helvia; Luthringer, Berengere Julie Christine; Feyerabend, Frank; Jimbo, Ryo; Willumeit-Römer, Regine; Wennerberg, Ann

    2015-01-01

    Background Magnesium alloys are of particular interest in medical science since they provide compatible mechanical properties with those of the cortical bone and, depending on the alloying elements, they have the capability to tailor the degradation rate in physiological conditions, providing alternative bioresorbable materials for bone applications. The present study investigates the in vitro short-term response of human undifferentiated cells on three magnesium alloys and high-purity magnesium (Mg). Materials and Methods The degradation parameters of magnesium-silver (Mg2Ag), magnesium-gadolinium (Mg10Gd) and magnesium-rare-earth (Mg4Y3RE) alloys were analysed after 1, 2, and 3 days of incubation in cell culture medium under cell culture condition. Changes in cell viability and cell adhesion were evaluated by culturing human umbilical cord perivascular cells on corroded Mg materials to examine how the degradation influences the cellular development. Results and Conclusions The pH and osmolality of the medium increased with increasing degradation rate and it was found to be most pronounced for Mg4Y3RE alloy. The biological observations showed that HUCPV exhibited a more homogeneous cell growth on Mg alloys compared to high-purity Mg, where they showed a clustered morphology. Moreover, cells exhibited a slightly higher density on Mg2Ag and Mg10Gd in comparison to Mg4Y3RE, due to the lower alkalinisation and osmolality of the incubation medium. However, cells grown on Mg10Gd and Mg4Y3RE generated more developed and healthy cellular structures that allowed them to better adhere to the surface. This can be attributable to a more stable and homogeneous degradation of the outer surface with respect to the incubation time. PMID:26600388

  7. Low Temperature Synthesis of Magnesium Aluminate Spinel

    International Nuclear Information System (INIS)

    The low-temperature synthesis of magnesium-aluminum spinel is carried out by a method of thermal decomposition in combined precipitated hydrates. The fine material of magnesium-aluminium spinel with average size of coherent dispersion's area 4...5 nanometers is obtained. Magnesium-aluminum spinel and initial hydrates were investigated by methods of the differential thermal analysis, the x-ray phase analysis and measurements of weight loss during the dehydration and thermal decomposition. It is established that synthesis of magnesium-aluminum spinel occurs at temperature 300 degree C by method of the x-ray phase analysis

  8. Investigation of bacterial populations in a biological nutrient removal system

    OpenAIRE

    Kavanaugh, Rathi G.

    1991-01-01

    Bacterial populations proliferating in a pilot scale biological nutrient removal system (BNR) were studied. The objective of the research was to develop media and methods to identify bacterial populations in BNR systems. Samples were obtained from the last aerobic zone of a University of Cape Town (UCT)-type system. The most probable numbers (MPN) of bacteria in the samples were analyzed in liquid media containing volatile fatty acids as sole sources of carbon. Samples...

  9. In Vitro Corrosion and Cytocompatibility of ZK60 Magnesium Alloy Coated with Hydroxyapatite by a Simple Chemical Conversion Process for Orthopedic Applications

    OpenAIRE

    Bing Wang; Ping Huang; Caiwen Ou; Kaikai Li; Biao Yan; Wei Lu

    2013-01-01

    Magnesium and its alloys—a new class of degradable metallic biomaterials—are being increasingly investigated as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. However, the high corrosion rate in physiological environments prevents the clinical application of Mg-based materials. Therefore, the objective of this study was to develop a hydroxyapatite (HA) coating on ZK60 magnesium alloy substrates to mediate th...

  10. Magnesium substitution in the structure of orthopedic nanoparticles: A comparison between amorphous magnesium phosphates, calcium magnesium phosphates, and hydroxyapatites

    Energy Technology Data Exchange (ETDEWEB)

    Nabiyouni, Maryam, E-mail: maryam.nabiyouni@rockets.utoledo.edu [Department of Bioengineering, University of Toledo, Toledo, OH (United States); Ren, Yufu [Department of Mechanical, Industrial and Manufacturing Engineering, University of Toledo, Toledo, OH (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, University of Toledo, Toledo, OH (United States); Department of Surgery (Dentistry), University of Toledo, Toledo, OH (United States)

    2015-07-01

    As biocompatible materials, magnesium phosphates have received a lot of attention for orthopedic applications. During the last decade multiple studies have shown advantages for magnesium phosphate such as lack of cytotoxicity, biocompatibility, strong mechanical properties, and high biodegradability. The present study investigates the role of Mg{sup +2} and Ca{sup +2} ions in the structure of magnesium phosphate and calcium phosphate nanoparticles. To directly compare the effect of Mg{sup +2} and Ca{sup +2} ions on structure of nanoparticles and their biological behavior, three groups of nanoparticles including amorphous magnesium phosphates (AMPs) which release Mg{sup +2}, calcium magnesium phosphates (CMPs) which release Mg{sup +2} and Ca{sup +2}, and hydroxyapatites (HAs) which release Ca{sup +2} were studied. SEM, TEM, XRD, and FTIR were used to evaluate the morphology, crystallinity, and chemical properties of the particles. AMP particles were homogeneous nanospheres, whereas CMPs were combinations of heterogeneous nanorods and nanospheres, and HAs which contained heterogeneous nanosphere particles. Cell compatibility was monitored in all groups to determine the cytotoxicity effect of particles on studied MC3T3-E1 preosteoblasts. AMPs showed significantly higher attachment rate than the HAs after 1 day and both AMPs and CMPs showed significantly higher proliferation rate when compared to HAs after 7 days. Gene expression level of osteoblastic markers ALP, COL I, OCN, OPN, RUNX2 were monitored and they were normalized to GAPDH housekeeping gene. Beta actin expression level was monitored as the second housekeeping gene to confirm the accuracy of results. In general, AMPs and CMPs showed higher expression level of osteoblastic genes after 7 days which can further confirm the stimulating role of Mg{sup +}2 and Ca{sup +2} ions in increasing the proliferation rate, differentiation, and mineralization of MC3T3-E1 preosteoblasts. - Highlights: • Role of Mg{sup 2

  11. Magnesium Hydride for Load Levelling Energy Storage

    DEFF Research Database (Denmark)

    Vigeholm, B.

    Some of the magnesium properties essential to the applicability of the reaction Mg+H2⇆MgH2 as a hydrogen storage system have been investigated. Three magnesium powders with particle size smaller than 50 μm average diameter were cycled, over 31, 71 and 151 cycles respectively, at 675K (400°C...

  12. Molecular self-assembly for biological investigations and nanoscale lithography

    Science.gov (United States)

    Cheunkar, Sarawut

    Small, diffusible molecules when recognized by their binding partners, such as proteins and antibodies, trigger enzymatic activity, cell communication, and immune response. Progress in analytical methods enabling detection, characterization, and visualization of biological dynamics at the molecular level will advance our exploration of complex biological systems. In this dissertation, analytical platforms were fabricated to capture membrane-associated receptors, which are essential proteins in cell signaling pathways. The neurotransmitter serotonin and its biological precursor were immobilized on gold substrates coated with self-assembled monolayers (SAMs) of oligo(ethylene glycol)alkanethiols and their reactive derivatives. The SAM-coated substrates present the biologically selective affinity of immobilized molecules to target native membrane-associated receptors. These substrates were also tested for biospecificity using antibodies. In addition, small-molecule-functionalized platforms, expressing neurotransmitter pharmacophores, were employed to examine kinetic interactions between G-protein-coupled receptors and their associated neurotransmitters. The binding interactions were monitored using a quartz crystal microbalance equipped with liquid-flow injection. The interaction kinetics of G-protein-coupled serotonin 1A receptor and 5-hydroxytyptophan-functionalized surfaces were studied in a real-time, label-free environment. Key binding parameters, such as equilibrium dissociation constants, binding rate constants, and dissociative half-life, were extracted. These parameters are critical for understanding and comparing biomolecular interactions in modern biomedical research. By integrating self-assembly, surface functionalization, and nanofabrication, small-molecule microarrays were created for high-throughput screening. A hybrid soft-lithography, called microcontact insertion printing, was used to pattern small molecules at the dilute scales necessary for highly

  13. Corrosion behavior of magnesium and magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    I.M.Baghni; WU Yin-shun(吴荫顺); LI Jiu-qing(李久青); ZHANG Wei(张巍)

    2004-01-01

    The automotive industry has crossed the threshold from using magnesium alloys in interior applications such as instrument panels and steering wheels to unprotected environment such as oil pan, cylinder head and wheels. The expanding territory of magnesium leads to new challenges: mainly environmental degradation of the alloys used and how they can be protected. The present critical review is aimed at understanding the corrosion behavior of magnesium and magnesium alloys in industrial and marine environments, and the effect of microstructure, additive elements and inhibitors on the corrosion mechanism.

  14. Investigation of the main chemical properties of water-magnesium chloride solutions. Application to the understanding of stress corrosion phenomena in 17.12 Mo stainless steel

    International Nuclear Information System (INIS)

    This research thesis reports the investigation of the main chemical properties of concentrated aqueous solutions of MgCl2 and of their influence of stress corrosion of 17Cr-12Ni-2Mo stainless steel. It shows that the most important chemical properties are the equilibrium pH and the acidity range of MgCl2 aqueous solutions, and that they strongly depend on solution temperature and concentration. The medium pH is governed by the increased acidity of water in presence of Mg++ ions, while the acidity range is determined by a hydrolysis reaction of these ions which results in a precipitation of magnesium hydroxyl-chlorides. The investigation of stress corrosion behaviour of the steel in MgCl2 solutions with varying temperature and concentration shows that this behaviour comes down to a prevailing pH effect which results from the variation of these both parameters, with a not negligible but less important effect of temperature. A study of cracking surfaces indicates that it is possible to pass from a transgranular to an intergranular mode by a variation of either media aggressiveness (pH, temperature, voltage) or strain rate. These results are explained by a concept of kinetic factor which limits stress corrosion

  15. Investigation into the non-biological outputs of mechanical-biological treatment facilities.

    Science.gov (United States)

    Cook, Ed; Wagland, Stuart; Coulon, Frédéric

    2015-12-01

    Mechanical-biological and biological-mechanical treatment (MBT/BMT) are effective methods for reducing biogenic additions to landfill, producing fuel products and recovering recyclate from residual waste. However, large amounts of contamination in the non-biological outputs reduce their market value. The aim of this study was therefore to identify the principal drivers and barriers to the marketability of ferrous metals (MBTFe) and heavy inert rejects (MBTr) recovered from four UK MBT/BMT plants. The plants were either using biodrying or anaerobic digestion (AD-MBT) for biological processing. Samples were collected at the different recovery stage processes and characterised for elemental composition and particle size distribution. Results showed that processes at the two biodrying plants produced MBTFe with 10% less contamination by non-target materials than the two AD-MBT plants. Further to this, approximately 10% of the MBTFe fraction sampled at all four facilities comprised non-target material which had become entrapped in the folds of metal food containers. A possible cause is waste comminution in the cutting gap of the low-speed high-torque cutting mills. Upgrading MBTFe outputs could save the UK MBT/BMT industry up to £ 4.4 million per annum which equates to £ 230,000 per annum for an average sized facility (i.e. capacity 108,000 tpa). Glass content in the MBTr samples ranged between 44% and 62%, however all plants showed approximately 85% combined content of glass, bricks, stones and ceramics. The biodegradable content in the MBTr samples indicated that only minimal upgrade would be required to achieve the Landfill Directive requirements for inert waste. Again valorisation of MBTr could save the UK MBT/BMT industry up to £ 1.9 million pa which equates to £ 160,000 per annum for an average sized facility. PMID:26394679

  16. Phytochemical and biological investigation of Hymenocallis littoralis SALISB.

    Science.gov (United States)

    Abou-Donia, Amina H; Toaima, Soad M; Hammoda, Hala M; Shawky, Eman; Kinoshita, Eri; Takayama, Hiromitsu

    2008-02-01

    A phytochemical investigation of the bulbs and flowers of Hymenocallis littoralis SALISB., cultivated in Egypt, was carried out, which resulted in the isolation of four alkaloids, lycorine (1), hippeastrine (2), 11-hydroxyvittatine (3), and (+)-8-O-demethylmaritidine (4), and of two flavonoids, quercetin 3'-O-glucoside (5), and rutin (6). The volatile constituents of the plant flowers were analyzed for the first time by GC/MS, which led to the identification of 26 known compounds (Table 1). Finally, the antimicrobial activity of the petroleum ether extract of the flowers of H. littoralis was investigated. PMID:18293433

  17. Investigating Climate Change and Reproduction: Experimental Tools from Evolutionary Biology

    Directory of Open Access Journals (Sweden)

    Oliver Y. Martin

    2012-09-01

    Full Text Available It is now generally acknowledged that climate change has wide-ranging biological consequences, potentially leading to impacts on biodiversity. Environmental factors can have diverse and often strong effects on reproduction, with obvious ramifications for population fitness. Nevertheless, reproductive traits are often neglected in conservation considerations. Focusing on animals, recent progress in sexual selection and sexual conflict research suggests that reproductive costs may pose an underestimated hurdle during rapid climate change, potentially lowering adaptive potential and increasing extinction risk of certain populations. Nevertheless, regime shifts may have both negative and positive effects on reproduction, so it is important to acquire detailed experimental data. We hence present an overview of the literature reporting short-term reproductive consequences of exposure to different environmental factors. From the enormous diversity of findings, we conclude that climate change research could benefit greatly from more coordinated efforts incorporating evolutionary approaches in order to obtain cross-comparable data on how individual and population reproductive fitness respond in the long term. Therefore, we propose ideas and methods concerning future efforts dealing with reproductive consequences of climate change, in particular by highlighting the advantages of multi-generational experimental evolution experiments.

  18. Alkalization is responsible for antibacterial effects of corroding magnesium.

    Science.gov (United States)

    Rahim, Muhammad Imran; Eifler, Rainer; Rais, Bushra; Mueller, Peter P

    2015-11-01

    Magnesium alloys are presently investigated as potential medical implant materials for temporary applications. Magnesium has been reported to have antibacterial activities and could therefore be used to prevent antibiotic treatment-resistant bacterial implant infections. For characterizing the effects of magnesium on infectious bacteria, bioluminescent S. aureus or P. aeruginosa were employed. The proliferation of both types of bacteria was suppressed in the presence of metallic magnesium and also in aqueous magnesium corrosion extracts. Of the two soluble corrosion products, magnesium ions were well tolerated while antibacterial activities correlated with increased pH levels of the supernatants. The alkaline pH alone was sufficient for the antibacterial effects which were completely abolished when the pH of the corrosion supernatants was neutralized. These results demonstrate that pH increases are necessary and sufficient for the antibacterial activity of metallic magnesium. In an animal model magnesium implants showed an enhanced but variable resistance to bacterial colonization. PMID:25974048

  19. Choline Magnesium Trisalicylate

    Science.gov (United States)

    Choline magnesium trisalicylate is used to relieve the pain, tenderness, inflammation (swelling), and stiffness caused by arthritis and painful ... used to relieve pain and lower fever. Choline magnesium trisalicylate is in a class of nonsteroidal anti- ...

  20. Magnesium and Space Flight

    Science.gov (United States)

    Smith, Scott M.; Zwart, Sara R.

    2016-01-01

    Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in astronauts before, during, and after space missions, in 43 astronauts (34 male, 9 female) on 4-6 month space flight missions. We also studied individuals participating in a ground analog of space flight, (head-down tilt bed rest, n=27, 35 +/- 7 y). We evaluated serum concentration and 24-hour urinary excretion of magnesium along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-d space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4- to 6-month space missions.

  1. Magnesium and Space Flight

    Directory of Open Access Journals (Sweden)

    Scott M. Smith

    2015-12-01

    Full Text Available Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in 43 astronauts (34 male, 9 female; 47 ± 5 years old, mean ± SD before, during, and after 4–6-month space missions. We also studied individuals participating in a ground analog of space flight (head-down-tilt bed rest; n = 27 (17 male, 10 female, 35 ± 7 years old. We evaluated serum concentration and 24-h urinary excretion of magnesium, along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-day space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4–6-month space missions.

  2. Study on crystal transformation process of magnesium carbonate hydrate based on salt lake magnesium resource utilization

    OpenAIRE

    Du, Juan; Chen, Zhen; WU, Yu-Long; YANG, Ming-De

    2013-01-01

    The crystal transformation process of magnesium carbonate hydrate by the reaction of magnesium sulfate (MgSO4) with ammonium carbonate [(NH4)2CO3] was investigated. MgSO4 is one of the main magnesium resources of the Lop Nur salt lake in the Xinjiang Autonomous Region of China. Magnesium carbonate hydrates with different chemical compositions were prepared. The transformation process of the 2 crystals, MgSO4 and (NH4)2CO3, was analyzed by Raman spectroscopy, and the associated chang...

  3. 8. International Conference on Pulse Investigations in Chemistry, Biology and Physics - PULS'2008. Abstracts

    International Nuclear Information System (INIS)

    The Report comprises abstracts of 68 communications (oral and posters) presented during the 8. International Conference on Pulse Investigations in Chemistry, Biology and Physics - PULS'2008, held on September 6 - 12, 2008 in Cracow. Presentations cover a variety of research fields representing different fields of pulse radiolysis in chemistry, biology and physics

  4. An Investigation of Physico-Mechanical Properties of Ultrafine-Grained Magnesium Alloys Subjected to Severe Plastic Deformation

    Science.gov (United States)

    Kozulyn, A. A.; Skripnyak, V. A.; Krasnoveikin, V. A.; Skripnyak, V. V.; Karavatskii, A. K.

    2015-01-01

    The results of investigations of physico-mechanical properties of specimens made from the structural Mg-based alloy (Russian grade Ma2-1) in its coarse-grained and ultrafine-grained states after SPD processing are presented. To form the ultrafine-grained structure, use was made of the method of orthogonal equal-channel angular pressing. After four passes through the die, a simultaneous increase was achieved in microhardness, yield strength, ultimate tensile strength and elongation to failure under conditions of uniaxial tensile loading.

  5. Magnesium and the Athlete.

    Science.gov (United States)

    Volpe, Stella Lucia

    2015-01-01

    Magnesium is the fourth most abundant mineral and the second most abundant intracellular divalent cation in the body. It is a required mineral that is involved in more than 300 metabolic reactions in the body. Magnesium helps maintain normal nerve and muscle function, heart rhythm (cardiac excitability), vasomotor tone, blood pressure, immune system, bone integrity, and blood glucose levels and promotes calcium absorption. Because of magnesium's role in energy production and storage, normal muscle function, and maintenance of blood glucose levels, it has been studied as an ergogenic aid for athletes. This article will cover the general roles of magnesium, magnesium requirements, and assessment of magnesium status as well as the dietary intake of magnesium and its effects on exercise performance. The research articles cited were limited from those published in 2003 through 2014. PMID:26166051

  6. Investigation of texture, microstructure, and mechanical properties of a magnesium-lanthanum alloy after thermo-mechanical processing

    Energy Technology Data Exchange (ETDEWEB)

    Elfiad, Djazia; Bourezg, Yousf Islem; Bradai, Djamel [USTHB, Algiers (Algeria). Faculty of Physics; Azzeddine, Hiba [USTHB, Algiers (Algeria). Faculty of Physics; M' sila Univ. (Algeria). Dept. of Physics

    2016-04-15

    The texture, microstructure, and mechanical properties of Mg-1.33La (wt.%) alloy after hot rolling and cold plane strain compression were investigated by using X-ray diffraction, optical microscopy, and micro-hardness measurements. This thermo-mechanical processing resulted in a relative weakening of the texture that was mainly a basal type. The microstructures after hot rolling and cold plane strain compression revealed the presence of a second phase (Mg{sub 17}La{sub 2}), mostly at grain boundaries. Twins were profuse, and their morphologies were quite different after hot rolling and cold plane strain compression. The Mg-1.33La (wt.%) alloy exhibited good room temperature formability and an increase in strength. The alloy's hardness increased with increasing deformation strain. Such properties were explained by the effect of both the Mg{sub 17}La{sub 2} phase precipitation and the sample's texture.

  7. Magnesium Metabolism and its Disorders

    OpenAIRE

    Swaminathan, R.

    2003-01-01

    Magnesium is the fourth most abundant cation in the body and plays an important physiological role in many of its functions. Magnesium balance is maintained by renal regulation of magnesium reabsorption. The exact mechanism of the renal regulation is not fully understood. Magnesium deficiency is a common problem in hospital patients, with a prevalence of about 10%. There are no readily available and easy methods to assess magnesium status. Serum magnesium and the magnesium tolerance test are ...

  8. Promoting coherent minimum reporting guidelines for biological and biomedical investigations: the MIBBI project

    Science.gov (United States)

    Taylor, Chris F; Field, Dawn; Sansone, Susanna-Assunta; Aerts, Jan; Apweiler, Rolf; Ashburner, Michael; Ball, Catherine A; Binz, Pierre-Alain; Bogue, Molly; Booth, Tim; Brazma, Alvis; Brinkman, Ryan R; Clark, Adam Michael; Deutsch, Eric W; Fiehn, Oliver; Fostel, Jennifer; Ghazal, Peter; Gibson, Frank; Gray, Tanya; Grimes, Graeme; Hancock, John M; Hardy, Nigel W; Hermjakob, Henning; Julian, Randall K; Kane, Matthew; Kettner, Carsten; Kinsinger, Christopher; Kolker, Eugene; Kuiper, Martin; Le Novère, Nicolas; Leebens-Mack, Jim; Lewis, Suzanna E; Lord, Phillip; Mallon, Ann-Marie; Marthandan, Nishanth; Masuya, Hiroshi; McNally, Ruth; Mehrle, Alexander; Morrison, Norman; Orchard, Sandra; Quackenbush, John; Reecy, James M; Robertson, Donald G; Rocca-Serra, Philippe; Rodriguez, Henry; Rosenfelder, Heiko; Santoyo-Lopez, Javier; Scheuermann, Richard H; Schober, Daniel; Smith, Barry; Snape, Jason; Stoeckert, Christian J; Tipton, Keith; Sterk, Peter; Untergasser, Andreas; Vandesompele, Jo; Wiemann, Stefan

    2009-01-01

    The Minimum Information for Biological and Biomedical Investigations (MIBBI) project provides a resource for those exploring the range of extant minimum information checklists and fosters coordinated development of such checklists. PMID:18688244

  9. The role of magnesium in the electrochemical behaviour of 5XXX aluminium-magnesium alloys

    NARCIS (Netherlands)

    Flores Ramirez, J.R.

    2006-01-01

    An investigation concerning the effects of magnesium on the intergranular corrosion susceptibility of AA5XXX aluminium alloys was carried out. In the present work, magnesium is found to be highly mobile in the bulk metal as well as in the aluminium oxide. This mobility is also found to be dependent

  10. Investigation of possible replacement of protective magnesium oxide layer in plasma display panels by barium ternary oxides

    International Nuclear Information System (INIS)

    The firing voltage (FV) of gas discharge in a test cell of plasma display materials was investigated for standard protective layers of MgO deposited by electron beam, and ternary BaY2O4 and BaGa2O4 oxides grown by pulsed laser deposition on the special dielectric coated glass substrates. The determined FVs for MgO (160 V), BaY2O4 (210 V) and BaGa2O4 (257 V) lead to the conclusion that a replacement of MgO by these ternary oxides is not expedient for plasma display panels. Using results from luminescence spectroscopy, values for the energy gap Eg ∼ 6.2 and 5.8 eV were estimated for BaY2O4 and BaGa2O4, respectively. The main reason for the observed high FVs is attributed to strong electron affinities χ, where χ (BaY2O4) 2O4)

  11. Investigation about thermal conductivities of La2Ce2O7 doped with calcium or magnesium for thermal barrier coatings

    International Nuclear Information System (INIS)

    Highlights: ► These ceramic materials with fluorite structure were synthesized. ► Oxygen vacancies lead to their lower thermal conductivities. ► These ceramics can be explored as novel candidate ceramic materials for TBCs. - Abstract: The La2Ce2O7 powders doped with Ca and Mg were synthesized by sol–gel method in this paper and their dense bulk samples were also prepared by pressure-less sintering at 1600 °C for 10 h. Their phase compositions, microstructures and thermal conductivities were investigated, respectively. XRD results reveal that single-phase (La0.95Ca0.05)2Ce2O6.95 and (La0.95Mg0.05)2Ce2O6.95 ceramics with fluorite structure are successfully synthesized. SEM and EDS results show that their microstructures are very dense and no other unreacted oxides or interphases exist in the interfaces between grains. Their thermal conductivities are lower than that of YSZ, which can be attributed to the phonon scattering caused by vacancies in their crystal lattices. The larger differences in atomic weight and ionic radius between Mg and La lead to the lower thermal conductivity of (La0.95Mg0.05)2Ce2O6.95 than that of (La0.95Ca0.05)2Ce2O6.95. The synthesized rare earth cerium oxides have potentials to be used as novel candidate materials for thermal barrier coatings in the future.

  12. The investigation of different particle size magnesium-doped zinc oxide (Zn0.92Mg0.08O) nanoparticles on the lubrication behavior of paraffin oil

    Science.gov (United States)

    Kalyani; Jaiswal, V.; Rastogi, R. B.; Kumar, D.

    2015-06-01

    Magnesium-doped zinc oxide (Zn0.92Mg0.08O) (ZMO) nanoparticles of 23 nm particle size have been synthesized by auto-combustion method. The variation in particle size of these nanoparticles has been performed by their further calcination at 800 and 1000 °C for 2 h and the corresponding calcined particles are designated as ZMO-1 and ZMO-2, respectively. The nanoparticles have been characterized by powder-XRD, scanning electron microscopy (SEM), energy dispersive X-ray and transmission electron microscope. The effect of particle size on the antiwear lubrication behavior of paraffin base oil has been investigated on four-ball lubricant tester. The tribological tests of these nanoparticles as antiwear additives have been studied at an optimized concentration (0.5 %w/v) by varying load for 30 min test duration and by varying the test durations at 392 N load. Various tribological parameters such as mean wear scar diameter, friction coefficient (µ), mean wear volume, running-in and steady-state wear rates show that these nanoparticles act as efficient antiwear additives and possess high load-carrying ability. From these tribological tests it has been observed that the lubrication behavior of studied nanoparticles is strongly size-dependent. The best tribological behavior is shown by nanoparticles of the smallest size, ZMO. Being sulfur, halogen and phosphorous free, ZMO nanoparticles have potential to be used as low SAPS lubricant additives. The SEM and atomic force microscopy analysis of the worn surfaces lubricated with ZMO nanoparticles at 392 N applied load for 60 min test duration show drastic decrease in surface roughness. The values of surface roughness of different additives are in good agreement with their observed tribological behavior.

  13. Experimental Investigation of Magnesium-Base Nanocomposite Produced by Friction Stir Processing: Effects of Particle Types and Number of Friction Stir Processing Passes

    Science.gov (United States)

    Asadi, P.; Faraji, G.; Masoumi, A.; Besharati Givi, M. K.

    2011-09-01

    In this research, nanosized SiC and Al2O3 particles were added to as-cast AZ91 magnesium alloy, and surface nanocomposite layers with ultrafine-grained structure were produced via friction stir processing (FSP). Effects of reinforcing particle types and FSP pass number on the powder distribution pattern, microstructure, microhardness, and on tensile and wear properties of the developed surfaces were investigated. Results show that the created nanocomposite layer by SiC particles exhibits a microstructure with smaller grains and higher hardness, strength, and elongation compared to the layer by Al2O3 particles. SiC particles do not stick together and are distributed separately in the AZ91 matrix; however, distribution of SiC particles is not uniform in all parts of the stirred zone (SZ), which causes heterogeneity in microstructure, hardness, and wear mechanism of the layer. Al2O3 particles are agglomerated in the different points of matrix and create alumina clusters. However, distribution of Al2O3 clusters in all parts of the SZ is uniform and results in a uniform microstructure. In the specimen produced by one-pass FSP and SiC particles, the wear mechanism changes in different zones of SZ due to the nonuniform distribution of particles. However, in the specimen produced by Al2O3 particles, the wear mechanism in all parts of the SZ is the same and, in addition to the abrasive wear, delamination also occurs. Increasing FSP pass number results in improved distribution of particles, finer grains, and higher hardness, strength, elongation, and wear resistance.

  14. Investigation of atomic layer deposition of magnesium oxide on a CoFeB layer for three-dimensional magnetic tunneling junctions

    International Nuclear Information System (INIS)

    Highlights: • ALD process deposited poly crystalline MgO films and oxidized bottom CoFeB layer. • Plasma enhanced ALD MgO process oxidized about 5 nm thick layer of CoFeB. • Thermal ALD MgO process oxidized just a few Å thickness of CoFeB. • Mainly FeOx formed by oxidation of CoFeB. -- Abstract: In this study, we comparatively investigated thermal- and plasma-enhanced atomic layer deposition (Th- and PE-ALD) of MgO on a CoFeB layer. MgCp2 (Bis(cyclopentadienyl)magnesium) was used as a Mg precursor and H2O and O2 plasma were employed as reactants for the Th- and PE-ALD process, respectively. Th- and PE-ALD MgO formed interlayer between MgO and CoFeB layer due to the oxidation of CoFeB by H2O and O2 plasma during the Th- and PE-ALD process. While interlayer formation was observed to be less than 1 nm for Th-ALD MgO, the PE-ALD MgO process resulted in an approximately 5 nm thick, predominantly FeOx oxidation of CoFeB. This was due to the high reactivity of the O radicals and the higher driving force of Fe for oxidation when compared with Co. Our results show that the Th-ALD MgO process has a better potential as a deposition technique to form tunnel barrier of magnetic tunneling junctions (MTJs)

  15. Investigation of atomic layer deposition of magnesium oxide on a CoFeB layer for three-dimensional magnetic tunneling junctions

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jeong-Gyu; Park, Jusang; Yoon, Jaehong [School of Electrical and Electronics Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul (Korea, Republic of); Kim, Keewon; Jang, Youngman; Kim, Kwangseok [Samsung Advanced Institute of Technology (SAIT), Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of); Kim, Hyungjun, E-mail: hyungjun@yonsei.ac.kr [School of Electrical and Electronics Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul (Korea, Republic of)

    2014-03-05

    Highlights: • ALD process deposited poly crystalline MgO films and oxidized bottom CoFeB layer. • Plasma enhanced ALD MgO process oxidized about 5 nm thick layer of CoFeB. • Thermal ALD MgO process oxidized just a few Å thickness of CoFeB. • Mainly FeO{sub x} formed by oxidation of CoFeB. -- Abstract: In this study, we comparatively investigated thermal- and plasma-enhanced atomic layer deposition (Th- and PE-ALD) of MgO on a CoFeB layer. MgCp{sub 2} (Bis(cyclopentadienyl)magnesium) was used as a Mg precursor and H{sub 2}O and O{sub 2} plasma were employed as reactants for the Th- and PE-ALD process, respectively. Th- and PE-ALD MgO formed interlayer between MgO and CoFeB layer due to the oxidation of CoFeB by H{sub 2}O and O{sub 2} plasma during the Th- and PE-ALD process. While interlayer formation was observed to be less than 1 nm for Th-ALD MgO, the PE-ALD MgO process resulted in an approximately 5 nm thick, predominantly FeO{sub x} oxidation of CoFeB. This was due to the high reactivity of the O radicals and the higher driving force of Fe for oxidation when compared with Co. Our results show that the Th-ALD MgO process has a better potential as a deposition technique to form tunnel barrier of magnetic tunneling junctions (MTJs)

  16. Magnesium and Osteoporosis

    Directory of Open Access Journals (Sweden)

    Ferda Özdemir

    2004-03-01

    Full Text Available Osteoporosis (OP is a condition of bone fragility resulting from micro-architectural deterioration and decreased bone mass. OP depends on the interaction of genetic, hormonal, environmental and nutritional factors. Chronic low intakes of vitamin D and possibly magnesium, zinc, fluoride and vitamins K, B12, B6 and folic acid may predispose to osteoporosis. Magnesium is a mineral needed by every cell of your body. It helps maintain normal muscle and nerve function, keeps heart rhythm steady, and bones strong. Mg serves as co-factors for enzymes that help build bone matrix. Magnesium deficiency occurs due to excessive loss of magnesium in urine, gastrointestinal system disorders that cause a loss of magnesium or limit magnesium absorption, or a chronic low intake of magnesium. Signs of magnesium deficiency include confusion, disorientation, loss of appetite, depression, muscle contractions and cramps, tingling, numbness, abnormal heart rhythms, coronary spasm, and seizures. Magnesium deficiency alters calcium metabolism and the hormones that regulates calcium. Several studies have suggested that magnesium supplementation may improve bone mineral density and prevent fractures.

  17. Magnesium in depression.

    Science.gov (United States)

    Serefko, Anna; Szopa, Aleksandra; Wlaź, Piotr; Nowak, Gabriel; Radziwoń-Zaleska, Maria; Skalski, Michał; Poleszak, Ewa

    2013-01-01

    Magnesium is one of the most essential mineral in the human body, connected with brain biochemistry and the fluidity of neuronal membrane. A variety of neuromuscular and psychiatric symptoms, including different types of depression, was observed in magnesium deficiency. Plasma/serum magnesium levels do not seem to be the appropriate indicators of depressive disorders, since ambiguous outcomes, depending on the study, were obtained. The emergence of a new approach to magnesium compounds in medical practice has been seen. Apart from being administered as components of dietary supplements, they are also perceived as the effective agents in treatment of migraine, alcoholism, asthma, heart diseases, arrhythmias, renal calcium stones, premenstrual tension syndrome etc. Magnesium preparations have an essential place in homeopathy as a remedy for a range of mental health problems. Mechanisms of antidepressant action of magnesium are not fully understood yet. Most probably, magnesium influences several systems associated with development of depression. The first information on the beneficial effect of magnesium sulfate given hypodermically to patients with agitated depression was published almost 100 years ago. Numerous pre-clinical and clinical studies confirmed the initial observations as well as demonstrated the beneficial safety profile of magnesium supplementation. Thus, magnesium preparations seem to be a valuable addition to the pharmacological armamentarium for management of depression. PMID:23950577

  18. Imparting passivity to vapor deposited magnesium alloys

    Science.gov (United States)

    Wolfe, Ryan C.

    Magnesium has the lowest density of all structural metals. Utilization of low density materials is advantageous from a design standpoint, because lower weight translates into improved performance of engineered products (i.e., notebook computers are more portable, vehicles achieve better gas mileage, and aircraft can carry more payload). Despite their low density and high strength to weight ratio, however, the widespread implementation of magnesium alloys is currently hindered by their relatively poor corrosion resistance. The objective of this research dissertation is to develop a scientific basis for the creation of a corrosion resistant magnesium alloy. The corrosion resistance of magnesium alloys is affected by several interrelated factors. Among these are alloying, microstructure, impurities, galvanic corrosion effects, and service conditions, among others. Alloying and modification of the microstructure are primary approaches to controlling corrosion. Furthermore, nonequilibrium alloying of magnesium via physical vapor deposition allows for the formation of single-phase magnesium alloys with supersaturated concentrations of passivity-enhancing elements. The microstructure and surface morphology is also modifiable during physical vapor deposition through the variation of evaporation power, pressure, temperature, ion bombardment, and the source-to-substrate distance. Aluminum, titanium, yttrium, and zirconium were initially chosen as candidates likely to impart passivity on vapor deposited magnesium alloys. Prior to this research, alloys of this type have never before been produced, much less studied. All of these metals were observed to afford some degree of corrosion resistance to magnesium. Due to the especially promising results from nonequilibrium alloying of magnesium with yttrium and titanium, the ternary magnesium-yttrium-titanium system was investigated in depth. While all of the alloys are lustrous, surface morphology is observed under the scanning

  19. Magnesium status and association with diabetes in the Taiwanese elderly.

    Science.gov (United States)

    Wang, Jui-Line; Shaw, Ning-Sing; Yeh, Hsiang-Yu; Kao, Mei-Ding

    2005-01-01

    The average dietary intake of magnesium is below recommended dietary allowances in many affluent Western countries. Prolonged low magnesium intake tends to result in hypomagnesaemia which might increase the risk of chronic diseases in elderly people. A national population-based cross-sectional nutrition survey, the Elderly Nutrition and Health Survey in Taiwan (1999-2000), was used to investigate the magnesium status and association with diabetes in the Taiwanese elderly. Dietary magnesium intake was based on 24-hour dietary recalls. Blood biochemical parameters including plasma magnesium and blood glucose were also measured. Average magnesium intake was 250 mg in men and 216 mg in women, which is equivalent to 68-70% of relevant Taiwanese Dietary Reference Intakes. The mean plasma magnesium concentration was 0.903 mmol/L in men and 0.906 mmol/L in women. The prevalence of a plasma magnesium level of vegans had a significantly lower magnesium intake than ovo-lacto vegetarians and non-vegetarians. Diabetic men and women had significantly higher blood glucose levels than non-diabetics. The risk of diabetes was elevated 3.25 times at plasma magnesium levelsdeficiency, may not be sufficient to reduce the risk of diabetes in the elderly. Further prospective study is required to help explain the differential results between dietary and plasma magnesium levels. PMID:16169838

  20. Serum magnesium and irradiation

    International Nuclear Information System (INIS)

    Serum magnesium determinations were obtained on 10 dogs and 11 patients undergoing fractionated irradiation to the pelvis and lower abdomen. Five of the dogs received oral prednisone during irradiation. There was no significant change in magnesium concentration in either the control dogs or the patients, but there was a significant increase in stool frequency in both the dogs and patients. A significant increase in magnesium concentration was noted in the dogs receiving prednisone. It is concluded that radiation-induced diarrhea is not caused by reduced serum magnesium concentration

  1. Radioactive {sup 210}Po in magnesium supplements

    Energy Technology Data Exchange (ETDEWEB)

    Struminska-Parulska, Dagmara Ida [Gdansk Univ. (Poland). Environmental Chemistry and Radiochemistry Chair

    2016-08-01

    The aim of this pioneer study was to determine polonium {sup 210}Po in the most popular magnesium supplements in Poland and estimate the possible related dose assessment to the consumers. The analyzed magnesium pharmaceutics contained organic or inorganic magnesium compounds; some from natural sources. The objectives of this research were to investigate the naturally occurring {sup 210}Po activity concentrations in magnesium supplements, find the correlations between {sup 210}Po concentration in medicament and magnesium chemical form, and calculate the effective radiation dose connected to analyzed magnesium supplement consumption. The highest {sup 210}Po activity concentrations were determined in mineral tablets made from sedimentary rocks, namely dolomite - 3.84 ± 0.15 mBq g{sup -1} (sample Mg17). The highest annual radiation dose from {sup 210}Po taken with 1 tablet of magnesium supplement per day or with 400 mg of pure Mg daily would come from sample Mg17 (dolomite) - 1.35 ± 0.5 and 8.44 ± 0.33 μSv year{sup -1} respectively.

  2. Recycling of magnesium drive train components

    Institute of Scientific and Technical Information of China (English)

    Daniel FEGHNER; Carsten BLAWERT; Norbert HORT; Karl Ulrich KAINER

    2009-01-01

    With the development of new heat resistant magnesium alloys, the automotive industry has introduced several parts to the drive train. The rising number of large magnesium components will result in a higher quantity of automotive post consumer scrap. It was the aim of this work to find a reasonable alloy system for the recycling of these magnesium drive train components. A matrix of potential recy-cling alloys based on the magnesium alloy AM50 was prepared via permanent mould casting. The ma-terials were investigated via tensile testing, creep tests and salt spray tests. Three alloys were selected for processing via high pressure die casting and the tests were repeated on the new materials. A promising system for recycling has been isolated and will be investigated more deeply for the influence of impurities.

  3. Recycling of magnesium drive train components

    Institute of Scientific and Technical Information of China (English)

    Daniel; FECHNER; Carsten; BLAWERT; Norbert; HORT; Karl; Ulrich; KAINER

    2009-01-01

    With the development of new heat resistant magnesium alloys, the automotive industry has introduced several parts to the drive train. The rising number of large magnesium components will result in a higher quantity of automotive post consumer scrap. It was the aim of this work to find a reasonable alloy system for the recycling of these magnesium drive train components. A matrix of potential recy-cling alloys based on the magnesium alloy AM50 was prepared via permanent mould casting. The materials were investigated via tensile testing, creep tests and salt spray tests. Three alloys were selected for processing via high pressure die casting and the tests were repeated on the new materials. A promising system for recycling has been isolated and will be investigated more deeply for the influence of impurities.

  4. Production of Magnesium by Vacuum Aluminothermic Reduction with Magnesium Aluminate Spinel as a By-Product

    Science.gov (United States)

    Wang, Yaowu; You, Jing; Peng, Jianping; Di, Yuezhong

    2016-03-01

    The Pidgeon process currently accounts for 85% of the world's magnesium production. Although the Pidgeon process has been greatly improved over the past 10 years, such production still consumes much energy and material and creates much pollution. The present study investigates the process of producing magnesium by employing vacuum aluminothermic reduction and by using magnesite as material and obtaining magnesium aluminate spinel as a by-product. The results show that compared with the Pidgeon process, producing magnesium by vacuum aluminothermic reduction can save materials by as much as 50%, increase productivity up to 100%, and save energy by more than 50%. It can also reduce CO2 emission by up to 60% and realize zero discharge of waste residue. Vacuum aluminothermic reduction is a highly efficient, low-energy-consumption, and environmentally friendly method of producing magnesium.

  5. Production of Magnesium by Vacuum Aluminothermic Reduction with Magnesium Aluminate Spinel as a By-Product

    Science.gov (United States)

    Wang, Yaowu; You, Jing; Peng, Jianping; Di, Yuezhong

    2016-06-01

    The Pidgeon process currently accounts for 85% of the world's magnesium production. Although the Pidgeon process has been greatly improved over the past 10 years, such production still consumes much energy and material and creates much pollution. The present study investigates the process of producing magnesium by employing vacuum aluminothermic reduction and by using magnesite as material and obtaining magnesium aluminate spinel as a by-product. The results show that compared with the Pidgeon process, producing magnesium by vacuum aluminothermic reduction can save materials by as much as 50%, increase productivity up to 100%, and save energy by more than 50%. It can also reduce CO2 emission by up to 60% and realize zero discharge of waste residue. Vacuum aluminothermic reduction is a highly efficient, low-energy-consumption, and environmentally friendly method of producing magnesium.

  6. Permeation of topically applied Magnesium ions through human skin is facilitated by hair follicles.

    Science.gov (United States)

    Chandrasekaran, Navin Chandrakanth; Sanchez, Washington Y; Mohammed, Yousuf H; Grice, Jeffrey E; Roberts, Michael S; Barnard, Ross T

    2016-06-01

    Magnesium is an important micronutrient essential for various biological processes and its deficiency has been linked to several inflammatory disorders in humans. Topical magnesium delivery is one of the oldest forms of therapy for skin diseases, for example Dead Sea therapy and Epsom salt baths. Some anecdotal evidence and a few published reports have attributed amelioration of inflammatory skin conditions to the topical application of magnesium. On the other hand, transport of magnesium ions across the protective barrier of skin, the stratum corneum, is contentious. Our primary aim in this study was to estimate the extent of magnesium ion permeation through human skin and the role of hair follicles in facilitating the permeation. Upon topical application of magnesium solution, we found that magnesium penetrates through human stratum corneum and it depends on concentration and time of exposure. We also found that hair follicles make a significant contribution to magnesium penetration. PMID:27624531

  7. Intradermal administration of magnesium sulphate and magnesium chloride produces hypesthesia to mechanical but hyperalgesia to heat stimuli in humans

    Directory of Open Access Journals (Sweden)

    Ikemoto Tatsunori

    2009-08-01

    Full Text Available Abstract Background Although magnesium ions (Mg2+ are known to display many similar features to other 2+ charged cations, they seem to have quite an important and unique role in biological settings, such as NMDA blocking effect. However, the role of Mg2+ in the neural transmission system has not been studied as sufficiently as calcium ions (Ca2+. To clarify the sensory effects of Mg2+ in peripheral nervous systems, sensory changes after intradermal injection of Mg2+ were studied in humans. Methods Magnesium sulphate, magnesium chloride and saline were injected into the skin of the anterior region of forearms in healthy volunteers and injection-induced irritating pain ("irritating pain", for short, tactile sensation, tactile pressure thresholds, pinch-pain changes and intolerable heat pain thresholds of the lesion were monitored. Results Flare formation was observed immediately after magnesium sulphate or magnesium chloride injection. We found that intradermal injections of magnesium sulphate and magnesium chloride transiently caused irritating pain, hypesthesia to noxious and innocuous mechanical stimulations, whereas secondary hyperalgesia due to mechanical stimuli was not observed. In contrast to mechanical stimuli, intolerable heat pain-evoking temperature was significantly decreased at the injection site. In addition to these results, spontaneous pain was immediately attenuated by local cooling. Conclusion Membrane-stabilizing effect and peripheral NMDA-blocking effect possibly produced magnesium-induced mechanical hypesthesia, and extracellular cation-induced sensitization of TRPV1 channels was thought to be the primary mechanism of magnesium-induced heat hyperalgesia.

  8. Investigation of Exposure to Formaldehyde from Preserved Biological Specimens. Status Report.

    Science.gov (United States)

    Consumer Product Safety Commission, Washington, DC.

    This investigation of formaldehyde exposure in school laboratories, where its principal source is from preserved biological specimens, was undertaken because of concern over exposure levels reported in the literature. Information was obtained in two ways. A limited survey of schools was conducted to determine extent of students' use of preserved…

  9. Combined biological and physico-chemical treatment of filtered pig manure wastewater : pilot investigations

    NARCIS (Netherlands)

    Kalyuzhnyi, S.; Sklyar, V.; Epov, A.; Archipchenko, I.; Barboulina, I.; Orlova, O.; Klapwijk, A.

    2002-01-01

    Combined biological and physico-chemical treatment of filtered pig manure wastewater has been investigated on the pilot installation operated under ambient temperatures (15-20°C) and included: i) UASB-reactor for elimination of major part of COD from the filtrate; (ii) stripper of CO2 fluidised bed

  10. Cloning Yeast Actin cDNA Leads to an Investigative Approach for the Molecular Biology Laboratory

    Science.gov (United States)

    Black, Michael W.; Tuan, Alice; Jonasson, Erin

    2008-01-01

    The emergence of molecular tools in multiple disciplines has elevated the importance of undergraduate laboratory courses that train students in molecular biology techniques. Although it would also be desirable to provide students with opportunities to apply these techniques in an investigative manner, this is generally not possible in the…

  11. Magnesium deficiency: what's our status?

    Science.gov (United States)

    Low magnesium intake has been implicated in a broad range of cardiometabolic conditions, including diabetes, hypertension, and cardiovascular disease. Dietary magnesium and total body magnesium status have a widely-used but imperfect biomarker in serum magnesium. Despite serum magnesium’s limitation...

  12. Mechanistic Study of Magnesium Carbonate Semibatch Reactive Crystallization with Magnesium Hydroxide and CO2

    DEFF Research Database (Denmark)

    Han, B.; Qu, H. Y.; Niemi, H.;

    2014-01-01

    This work investigates semibatch precipitation of magnesium carbonate at ambient temperature and pressure using Mg(OH)(2) and CO2 as starting materials. A thermal analysis method was developed that reflects the dissolution rate of Mg(OH)(2) and the formation of magnesium carbonate. The method...... the liquid and solid phases. A stirring rate of 650 rpm was found to be the optimum speed as the flow rate of CO2 was 1 L/min. Precipitation rate increased with gas flow rate, which indicates that mass transfer of CO2 plays a critical role in this precipitation case. Magnesium carbonate trihydrate...

  13. In Situ 13C NMR at Elevated-Pressures and -Temperatures Investigating the Conversion of CO2 to Magnesium and Calcium Carbonate Minerals

    Science.gov (United States)

    Surface, J. A.; Conradi, M. S.; Skemer, P. A.; Hayes, S. E.

    2013-12-01

    We have constructed specialized NMR hardware to conduct in situ elevated-pressure, elevated-temperature 13C NMR studies of unmixed heterogeneous mixtures of solids, liquids, gases, and supercritical fluids. Specifically, our aim is to monitor CO2 uptake in both ultramafic rocks and in more porous geological materials to understand the mechanisms of chemisorption as a function of temperature, pressure and pH. In this in situ NMR probe, we are able to simulate processes at geologically relevant fluid pressures and temperatures, monitoring the kinetics of CO2 conversion to carbonates. The in situ NMR experiments consist of heterogeneous mixtures of rock, salty brine solution, and moderate pressure CO2 gas at elevated temperatures. The purpose of studying these reactions is to determine efficacy of carbonate formation in various geological reservoirs. Via 13C NMR, we have spectroscopically characterized and quantified the conversion of CO2 to magnesium carbonate and calcium carbonate minerals. When CO2 reacts with the calcium or magnesium in a mineral or rock sample, the 13C chemical shift, linewidth, lineshape, and relaxation times change dramatically. This change can be monitored in situ and provide instantaneous and continuous characterization that maps the chemistry that is taking place. For example, on the pathway to MgCO3 formation, there are a number of phases of Mg(OH)x(H2O)y(CO3)z that are apparent via NMR spectroscopy. We will demonstrate that NMR can be used for quantitative characterization of multiple metastable mineral phases in pure forms and in mixtures. Results are confirmed via powder XRD and Raman spectroscopy of aquo- hydro- carbonato- magnesium species and calcium carbonate species. We also have monitored the 13C spectroscopy to analyze the phase of CO2 (liquid, supercritical, or gas) and its conversion into other forms, such as bicarbonate and carbonate species, providing a "window" into the in situ pH of the reacting system. Reference: 'In Situ

  14. Immunological Response to Biodegradable Magnesium Implants

    Science.gov (United States)

    Pichler, Karin; Fischerauer, Stefan; Ferlic, Peter; Martinelli, Elisabeth; Brezinsek, Hans-Peter; Uggowitzer, Peter J.; Löffler, Jörg F.; Weinberg, Annelie-Martina

    2014-04-01

    The use of biodegradable magnesium implants in pediatric trauma surgery would render surgical interventions for implant removal after tissue healing unnecessary, thereby preventing stress to the children and reducing therapy costs. In this study, we report on the immunological response to biodegradable magnesium implants—as an important aspect in evaluating biocompatibility—tested in a growing rat model. The focus of this study was to investigate the response of the innate immune system to either fast or slow degrading magnesium pins, which were implanted into the femoral bones of 5-week-old rats. The main alloying element of the fast-degrading alloy (ZX50) was Zn, while it was Y in the slow-degrading implant (WZ21). Our results demonstrate that degrading magnesium implants beneficially influence the immune system, especially in the first postoperative weeks but also during tissue healing and early bone remodeling. However, rodents with WZ21 pins showed a slightly decreased phagocytic ability during bone remodeling when the degradation rate reached its maximum. This may be due to the high release rate of the rare earth-element yttrium, which is potentially toxic. From our results we conclude that magnesium implants have a beneficial effect on the innate immune system but that there are some concerns regarding the use of yttrium-alloyed magnesium implants, especially in pediatric patients.

  15. Ductility enhancement of extruded magnesium via yttrium addition

    International Nuclear Information System (INIS)

    Two binary Mg-Y alloys and pure magnesium were prepared by extrusion. The effect of yttrium on mechanical properties was investigated in comparison between the pure magnesium and the Mg-Y alloys. The results showed that after extruded and annealed, with increment of the yttrium addition, the elongation-to-failure of magnesium increases, but the strength decreases. This is mainly due to the different textures that make the difference of deformation modes in tensile along ED direction for the pure magnesium and the Mg-Y alloys. The pure magnesium has the texture with {0 0 0 2} pole perpendicular to ED. However more random components of texture are formed in the Mg-Y alloys. Accordingly, the Mg-Y alloys can be deformed with more active dislocation slips than the pure magnesium.

  16. Growth Habit of the Basic Oxysulfate Magnesium Whisker

    Institute of Scientific and Technical Information of China (English)

    WU Jiansong; GAO Yimin

    2016-01-01

    The growth habit of the basic magnesium oxysulfate whisker was investigated based on the theoretical model of anion coordination polyhedron growth units. It is found that typical basic magnesium oxysulfate whisker growth is consistent with anion tetrahedral coordination incorporation rules. The growth units of basic magnesium oxysulfate whiskers are [Mg-(OH)4]2- and HSO4-. [Mg-(OH)4]2- is the favorable growth unit and whisker growth is in the direction of the [Mg-(OH)4]2- combination. A plurality of [Mg-(OH)4]2- s combine and become a larger dimensional growth unit in a one-dimensional direction. Then HSO4-and larger dimensional growth units connect as basic magnesium sulfate whiskers, according to the structural characteristics of the basic magnesium sulfate whisker, which can guide the synthesis of magnesium hydroxide whisker.

  17. Quantum chemical methods for the investigation of photoinitiated processes in biological systems: theory and applications.

    Science.gov (United States)

    Dreuw, Andreas

    2006-11-13

    With the advent of modern computers and advances in the development of efficient quantum chemical computer codes, the meaningful computation of large molecular systems at a quantum mechanical level became feasible. Recent experimental effort to understand photoinitiated processes in biological systems, for instance photosynthesis or vision, at a molecular level also triggered theoretical investigations in this field. In this Minireview, standard quantum chemical methods are presented that are applicable and recently used for the calculation of excited states of photoinitiated processes in biological molecular systems. These methods comprise configuration interaction singles, the complete active space self-consistent field method, and time-dependent density functional theory and its variants. Semiempirical approaches are also covered. Their basic theoretical concepts and mathematical equations are briefly outlined, and their properties and limitations are discussed. Recent successful applications of the methods to photoinitiated processes in biological systems are described and theoretical tools for the analysis of excited states are presented. PMID:17009357

  18. Optimization of Magnesium Metal into Commercially Pure Aluminium

    Directory of Open Access Journals (Sweden)

    Vandana J Rao

    2014-02-01

    Full Text Available The present investigation, involve development of Al-Mg systems by addition of magnesium into commercially pure aluminium. The amounts of magnesium added into commercially pure aluminium are of 1 and 2 wt%. The recoveries of magnesium are around 85-90%.Remaining Mg react with oxygen and float on the liquid aluminium. Presence of magnesium creates two phenomena. One is solid solution hardening and other is intermetallics formation. Both the phenomena checked by microstructural changes and by measuring the electrical conductivity values. By increasing the Mg, content mechanical properties (hardness and tensile strength increases and electrical conductivity decreases.

  19. Magnesium blood test

    Science.gov (United States)

    Magnesium - blood ... A blood sample is needed. ... When the needle is inserted to draw blood, some people feel slight pain. Others feel a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon ...

  20. Magnesium Aluminate Spinel

    Institute of Scientific and Technical Information of China (English)

    Yu Lingyan

    2012-01-01

    1 ScopeThis standard specifies the terms, definitions,classifications,technical requirements,test methods,inspection rules, packing, marking, transportation,storage,and quality certificate of magnesium aluminate spinel.

  1. Magnesium and Osteoporosis

    OpenAIRE

    Ferda Özdemir; Meliha Rodoplu

    2004-01-01

    Osteoporosis (OP) is a condition of bone fragility resulting from micro-architectural deterioration and decreased bone mass. OP depends on the interaction of genetic, hormonal, environmental and nutritional factors. Chronic low intakes of vitamin D and possibly magnesium, zinc, fluoride and vitamins K, B12, B6 and folic acid may predispose to osteoporosis. Magnesium is a mineral needed by every cell of your body. It helps maintain normal muscle and nerve function, keeps heart rhythm steady...

  2. Magnesium salts as compounds of the preparation of magnesium oxide from Tunisian natural brines

    Directory of Open Access Journals (Sweden)

    Behij Souheil

    2013-01-01

    Full Text Available Magnesium oxide is one of the most important magnesium compounds used in industry. The production of MgO is often done from calcined magnesium carbonate or from natural magnesium saline solutions (sea water and brines. In the case of these solutions, magnesium oxide is precipitated after the addition of a strong base (eg. Ammonia. Magnesium hydroxide is calcined after its separation from the excess resulting from the strong base through filtration. Thus, magnesia qualities may differ depending on several physical parameters and particularly on the nature of the compound. Consequently, two different compounds were selected: magnesium chloride and magnesium sulphate which can be recovered from Tunisian natural brines. Three physical factors were considered: calcination temperatures, precipitation temperatures and calcination time of Mg(OH2. The decomposition of Mg(OH2 was investigated by DTA/TGA. Mass losses vary in the range (23.0%-29.9%. Starting decomposition temperatures are between 362°C and 385°C. The MgO produced from MgSO4 under 1000°C within 48 hours of calcination time and with 40°C as a reaction temperature for Mg(OH2 shows a good crystallinity and is of a cristallyte size of 86.3 nm and has a specific surface area equal to 16.87 m2g-1. Finally, morphological differences between MgO agglomerates at different temperatures were observed by SEM. Consequently, magnesium sulphate as precursor for preparing MgO is selected.

  3. Solid state structural and theoretical investigations of a biologically active chalcone

    Science.gov (United States)

    Abbas, Asghar; Gökce, Halil; Bahceli, Semiha; Bolte, Michael; Naseer, Muhammad Moazzam

    2016-05-01

    The computational methods are presently emerging as an efficient and reliable tool for predicting structural properties of biologically important compounds. In the present manuscript, the solid state structural and theoretical investigations of a biologically active chalcone i-e (E)-3-(4-(hexyloxy)phenyl)-1-phenylprop-2-en-1-one (6c) have been reported. The solid state structure of 6c was measured by X-ray crystallographic technique whereas the optimized molecular geometry, vibrational frequencies, the simulated UV-vis spectra (in gas and in methanol solvent), 1H and 13C NMR chemical shift (in gas and in chloroform solvent) values, HOMO-LUMO analysis, the molecular electrostatic potential (MEP) surface and thermodynamic parameters were calculated by using DFT/B3LYP method with 6-311++G(d,p) basis set in ground state. The results of the theoretical investigations were found to be in good agreement with experimental data.

  4. Electrodeposition of magnesium and magnesium/aluminum alloys

    Science.gov (United States)

    Mayer, A.

    1988-01-21

    Electrolytes and plating solutions for use in processes for electroplating and electroforming pure magnesium and alloys of aluminum and magnesium and also electrodeposition processes. An electrolyte of this invention is comprised of an alkali metal fluoride or a quaternary ammonium halide, dimethyl magnesium and/or diethyl magnesium, and triethyl aluminum and/or triisobutyl aluminum. An electrolyte may be dissolved in an aromatic hydrocarbon solvent to form a plating solution. The proportions of the component compounds in the electrolyte are varied to produce essentially pure magnesium or magnesium/aluminum alloys having varying selected compositions.

  5. Investigating of conceptions of learning biology with respect to gender, grade level and school type

    OpenAIRE

    Sadi Özlem; Çevik Mustafa

    2016-01-01

    The aim of this study was to describe the students’ conceptions of learning biology (COLB) and investigate students’ COLB with respect to gender, grade level and school type. COLB questionnaire was implemented in 1691 high school students. In general, this study recognized students preferred higher-level conceptions of learning (increasing knowledge, application, understanding and seeing in a new way) to lower-level conceptions (memorizing, preparing for exams and calculating and practicing)....

  6. Investigations on the biological behaviour and the decorporation of 234Th in the rat

    International Nuclear Information System (INIS)

    In this work the biological behaviour of 234Th in the rat has been studied as function of mass, chemical form and route of entry. Further it was investigated if there is a correlation between iron metabolism and distribution of 234Th in the organism. The mobilization of 234Th with Ca- und Zn-DTPA as well as with other chelators and their combinations with DTPA has been determined as basis for acceptable therapeutic procedures for decorporation. (orig.)

  7. Grafting of organosilane derived from 3-glycidoxypropyltrimethoxysilane and thiourea onto magnesium phyllosilicate by sol-gel process and investigation of metal adsorption properties

    International Nuclear Information System (INIS)

    A layered inorganic-organic magnesium silicate (Mg-GTPS-TU) has been successfully synthesized by using sol-gel based precursor under mild temperature conditions and a new silylaing agent (GTPS-TU) derived from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. The hybrid material was characterized through elemental analysis, infrared spectroscopy, X-ray diffractometry, thermogravimetry, and carbon and silicon solid-state nuclear magnetic resonance spectroscopy. The result confirmed the attachment of organic functionality to the inorganic silicon network. The inter-lamellar distance for the hybrid material was found to be 18.8 A. Metal adsorption characteristics follows Cr(III) >Mn(II)>Zn(II) with more affinity towards Cr(III) in dilute aqueous solution. Evaluation of thermodynamic parameters ΔH and ΔS for Cr(III) were found to be 25.44 J mol-1 and 79.9 J mol-1 K-1, respectively, indicating adsorption process to be endothermic in nature. The negative value of ΔG indicated the feasibility and spontaneity of ongoing adsorption process at relatively higher temperature. The presence of multiple coordination sites in the attached organic functionality expresses the potentiality of the hybrid material containing new silylating agent for heavy cation removal from eco-system. - Abstract: We report the synthesis and adsorption properties of a layered inorganic-organic magnesium silicate (Mg-GTPS-TU) derived from a new silylaing agent from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. Display Omitted

  8. 75 FR 73045 - Magnesium Metal From the People's Republic of China: Rescission of Antidumping Duty...

    Science.gov (United States)

    2010-11-29

    ... Magnesium From the Russian Federation, 60 FR 25691 (May 12, 1995). (3) Products that contain 50% or greater... Investigation of Pure Magnesium from the Russian Federation, 60 FR 25691 (May 12, 1995); and Antidumping Duty Order: Pure Magnesium in Granular Form from the People's Republic of China, 66 FR 57936 (Nov. 19,...

  9. Combustion and extinction of magnesium fires

    International Nuclear Information System (INIS)

    The studies made in France on magnesium combustion and extinguishing means are associated at the nuclear fuel of the graphite-gas reactor. Safety studies are made for ameliorate our knowledge on: - magnesium combustion - magnesium fire propagation - magnesium fire extinguishing

  10. Borosilicate glass alteration driven by magnesium carbonates

    International Nuclear Information System (INIS)

    Highlights: ► We studied borosilicate glass/hydromagnesite interaction. ► Magnesium silicate precipitation increases glass alteration. ► Geochemical modeling allows to quantify the alteration mechanisms involved. - Abstract: The alteration of simplified synthetic glass, representative of the French reference nuclear glass R7T7, in presence of hydromagnesite has been experimentally investigated and modeled. Magnesium in solution is known to potentially enhance glass alteration; nuclear glass clayed host rocks contain magnesium and can dissolve to maintain the concentration of magnesium in solution. For modeling purposes, it was suitable to study a simple system. Hydromagnesite was therefore chosen as a simple model mineral in order to check the influence of an Mg-rich mineral on glass alteration. Since the models use thermodynamic and kinetic parameters measured in pure water and pH-buffered solutions, changing the solution composition or adding minerals is a key step towards the validation of the modeling assumptions before using the model for predictive purposes. Experiments revealed that glass alteration is enhanced in presence of hydromagnesite. Modeling was performed using the GRAAL model implemented within the CHESS/HYTEC reactive transport code. Modeling proved useful both for explaining the mechanisms involved and quantifying the impact on glass alteration: Mg coming from hydromagnesite dissolution reacts with Si provided by the glass in order to form magnesium silicates. This reaction decreases the pH down to neutral conditions where magnesium silicates are more soluble than at the natural alkali pH imposed by glass or hydromagnesite dissolution. The driving force of the magnesium silicate precipitation is eventually the interdiffusion of alkali within the altered amorphous glass layer as this mechanism consumes protons. The model’s ability to describe the concentrations of elements in solution and formed solids whatever the glass

  11. Laser surface treatment of cast magnesium alloys

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2009-02-01

    Full Text Available Purpose: The goal of this work was to investigate influence of laser treatment on structure and properties MCMgAl3Zn1, MCMgAl6Zn1, MCMgAl9Zn1 and MCMgAl12Zn1 cast magnesium alloys.Design/methodology/approach: Tests were made on the experimental MCMgAl3Zn1 MCMgAl6Zn1 MCMgAl9Zn1 and MCMgAl12Zn1 casting magnesium alloys. Laser treatment was made using the Rofin DL020 HPDL high power diode laser in the argon shield gas cover with the technique of the continuous powder supply to the remelted pool area.Findings: Investigations of the surface layers carried out confirm that laser treatment of the surface layer of the Mg-Al-Zn casting magnesium alloys is feasible using the HPDL high power diode laser ensuring better properties compared to alloys properties after the regular heat treatment after employing the relevant process parameters. Occurrences were found based on the metallographic examinations of the remelted zone (RZ and the heat affected zone (HAZ in alloyed surface layer of the investigated casting magnesium alloy.Research limitations/implications: This investigation presents different laser power and in this research was used two powders, namely tungsten-, and titanium carbide.Practical implications: Reinforcing the surface of cast magnesium alloys by adding TiC and WC particles is such a possible way to achieve the possibilities of the laser melt injection process, which is a potential technique to produce a Metal-Matrix Composite (MMC layer in the top layer of a metal workpiece.Originality/value: The originality of this work is applying of High Power Diode Laser for alloying of magnesium alloy using hard particles like tungsten- and titanium carbide.

  12. Building gene co-expression networks using transcriptomics data for systems biology investigations

    DEFF Research Database (Denmark)

    Kadarmideen, Haja; Watson-Haigh, Nathan S.

    2012-01-01

    connected within a network. The two GCN construction methods used were, Weighted Gene Co-expression Network Analysis (WGCNA) and Partial Correlation and Information Theory (PCIT) methods. Nodes were ranked based on their connectivity measures in each of the four different networks created by WGCNA and PCIT......Gene co-expression networks (GCN), built using high-throughput gene expression data are fundamental aspects of systems biology. The main aims of this study were to compare two popular approaches to building and analysing GCN. We use real ovine microarray transcriptomics datasets representing four...... and node ranks in two methods were compared to identify those nodes which are highly differentially ranked (HDR). A total of 1,017 HDR nodes were identified across one or more of four networks. We investigated HDR nodes by gene enrichment analyses in relation to their biological relevance to...

  13. 21 CFR 184.1434 - Magnesium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium phosphate. 184.1434 Section 184.1434 Food... Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic...

  14. Biologic

    CERN Document Server

    Kauffman, L H

    2002-01-01

    In this paper we explore the boundary between biology and the study of formal systems (logic). In the end, we arrive at a summary formalism, a chapter in "boundary mathematics" where there are not only containers but also extainers ><, entities open to interaction and distinguishing the space that they are not. The boundary algebra of containers and extainers is to biologic what boolean algebra is to classical logic. We show how this formalism encompasses significant parts of the logic of DNA replication, the Dirac formalism for quantum mechanics, formalisms for protein folding and the basic structure of the Temperley Lieb algebra at the foundations of topological invariants of knots and links.

  15. Synthesis of nanocrystalline magnesium nitride (Mg3N2) powder using thermal plasma

    International Nuclear Information System (INIS)

    Nanocrystalline magnesium nitride (Mg3N2) powder was synthesized from bulk magnesium by thermal plasma at atmospheric pressure. Magnesium vapor was generated through heating the bulk magnesium by DC plasma jet and reacted with ammonia gas. Injecting position and flow rates of ammonia gas were controlled to investigate an ideal condition for Mg3N2 synthesis. The synthesized Mg3N2 was cooled and collected on the chamber wall. Characteristics of the synthesized powders for each experimental condition were analyzed by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and thermogravity analysis (TGA). In absence of NH3, magnesium metal powder was formed. The synthesis with NH3 injection in low temperature region resulted in a formation of crystalline magnesium nitride with trigonal morphology, whereas the mixture of magnesium metal and amorphous Mg3N2 was formed when NH3 was injected in high temperature region. Also, vaporization process of magnesium was discussed.

  16. Aluminum Hydroxide and Magnesium Hydroxide

    Science.gov (United States)

    Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They ... They combine with stomach acid and neutralize it. Aluminum Hydroxide, Magnesium Hydroxide are available without a prescription. ...

  17. Magnesium production by carbothermic reduction in vacuum

    Directory of Open Access Journals (Sweden)

    Yang Tian

    2015-06-01

    Full Text Available In present work, we investigate production of magnesium by carbothermic reduction under vacuum conditions. The process was divided into two parts, one is reduction process, and the other one is condensation process. The experimental results revealed that during reduction process, the gas–solid reaction between MgO and CO was not occurred at a temperature and pressure of 1723 K and 30–100 Pa respectively. So the main reduction reaction was MgO(s + C(s = Mg(g + CO(g (under vacuum and reaction type belonged to solid–solid reaction. In Condensation Process, according to a contrast and analysis, the condensation quality of magnesium is associated with CO concentration. The resultant product C was formed and it followed magnesium vapor condensation which prevents mutual combination of two metal droplets to forms the compact condensation produces. Therefore, in order to compact morphological forms of magnesium crystal whiskers, we must control the technical conditions and find the method to separate the magnesium vapor and carbon monoxide. That's the key factor to get better crystalline structure.

  18. Post traumatic tetanus and role magnesium sulphate

    International Nuclear Information System (INIS)

    Tetanus is a life threatening disease. Reported mortality for tetanus is 15-39%. Conventional treatment includes heavy sedation and artificial ventilation. Complications resulting from long term heavy sedation and artificial ventilation contribute to 60% of the total mortality caused by tetanus. In this study magnesium sulphate was used to reduce the need for sedation and artificial ventilation. Objectives of this prospective study were to determine the role of magnesium sulphate in post traumatic tetanus. The study was carried out in surgical Intensive Care at Pakistan Institute of Medical Sciences (PIMS), Islamabad from Jan 2004 to Dec 2007. Forty-four patients presented during this period and 33 patients were included in the study. All patients had tracheostomy done within 48 hours. Every patient was started Magnesium Sulphate therapy for control of spasms after sending baseline investigations. Patients were given ventilatory support when needed. All data was entered in well structured proforma. SPSS-10 was used to analyse data. Thirty-three patients were included in the study and all patients were given magnesium sulphate. Out of these, 45.5% cases were grade 4 tetanus, 73.6% and 63.3% cases did not require artificial ventilation and additional sedation respectively, 51.1% patients remained free of complications of tetanus. Overall mortality was 30.3%. Use of Magnesium Sulphate is safe and reduces the need for sedation and artificial ventilation in high grade tetanus thus contributing to survival benefit in adult post-traumatic tetanus cases. (author)

  19. Biological Applications and Transmission Electron Microscopy Investigations of Mesoporous Silica Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Brian G. Trewyn

    2006-05-01

    The research presented and discussed within involves the development of novel biological applications of mesoporous silica nanoparticles (MSN) and an investigation of mesoporous material by transmission electron microscopy (TEM). Mesoporous silica nanoparticles organically functionalized shown to undergo endocytosis in cancer cells and drug release from the pores was controlled intracellularly and intercellularly. Transmission electron microscopy investigations demonstrated the variety of morphologies produced in this field of mesoporous silica nanomaterial synthesis. A series of room-temperature ionic liquid (RTIL) containing mesoporous silica nanoparticle (MSN) materials with various particle morphologies, including spheres, ellipsoids, rods, and tubes, were synthesized. By changing the RTIL template, the pore morphology was tuned from the MCM-41 type of hexagonal mesopores to rotational moire type of helical channels, and to wormhole-like porous structures. These materials were used as controlled release delivery nanodevices to deliver antibacterial ionic liquids against Escherichia coli K12. The involvement of a specific organosiloxane function group, covalently attached to the exterior of fluorescein doped mesoporous silica nanoparticles (FITC-MSN), on the degree and kinetics of endocytosis in cancer and plant cells was investigated. The kinetics of endocystosis of TEG coated FITC-MSN is significantly quicker than FITC-MSN as determined by flow cytometry experiments. The fluorescence confocal microscopy investigation showed the endocytosis of TEG coated-FITC MSN triethylene glycol grafted fluorescein doped MSN (TEG coated-FITC MSN) into both KeLa cells and Tobacco root protoplasts. Once the synthesis of a controlled-release delivery system based on MCM-41-type mesoporous silica nanorods capped by disulfide bonds with superparamagnetic iron oxide nanoparticles was completed. The material was characterized by general methods and the dosage and kinetics of the

  20. Inquiry-based laboratory investigations and student performance on standardized tests in biological science

    Science.gov (United States)

    Patke, Usha

    Achievement data from the 3rd International Mathematics and Sciences Study and Program for International Student Assessment in science have indicated that Black students from economically disadvantaged families underachieve at alarming rates in comparison to White and economically advantaged peer groups. The study site was a predominately Black, urban school district experiencing underachievement. The purpose of this correlational study was to examine the relationship between students' use of inquiry-based laboratory investigations and their performance on the Biology End of Course Test, as well as to examine the relationship while partialling out the effects of student gender. Constructivist theory formed the theoretical foundation of the study. Students' perceived levels of experience with inquiry-based laboratory investigations were measured using the Laboratory Program Variable Inventory (LPVI) survey. LPVI scores of 256 students were correlated with test scores and were examined by student gender. The Pearson correlation coefficient revealed a small direct correlation between students' experience in inquiry-based laboratory investigation classes and standardized test scores on the Biology EOCT. A partial correlational analysis indicated that the correlation remained after controlling for gender. This study may prompt a change from teacher-centered to student-centered pedagogy at the local site in order to increase academic achievement for all students. The results of this study may also influence administrators and policy makers to initiate local, state, or nationwide curricular development. A change in curriculum may promote social change as students become more competent, and more able, to succeed in life beyond secondary school.

  1. Investigative strategy for research on biological basis of traditional Chinese medicine syndrome: feature selection-based data mining methods

    Directory of Open Access Journals (Sweden)

    Jian-xin Chen

    2010-08-01

    Full Text Available This paper is devoted to discussing two research patterns of biological basis of traditional Chinese medicine syndrome and presenting a research strategy for data mining methods. It points out that data mining methods which are based on feature selection are better fit for investigating biological basis of traditional Chinese medicine syndrome. Based on such a discussion, the concept of “characteristic pattern” is proposed to bridge the gap between “golden index” and biological basis of traditional Chinese medicine syndrome. This paper presents a novel research avenue for investigating biological basis of traditional Chinese medicine syndrome.

  2. In vivo study of degradable magnesium and magnesium alloy as bone implant

    Institute of Scientific and Technical Information of China (English)

    HUANG Jingjing; REN Yibin; JIANG Yue; ZHANG Bingchun; YANG Ke

    2007-01-01

    In order to investigate the in vivo behavior of pure magnesium and AZ31B and the influence of mineralization induction ability,sample rods were implanted intramedullary into the femora of rabbits.After one and nine weeks,six animals from each group were sacrificed,respectively.Undecalcified cross-sections of implant were performed to observe bone-implant by scanning electron microscopy (SEM)and energy dispersive spectromicroscopy(EDS).The SEM/EDS evaluation showed that there is a thin layer of bone around magnesium and its alloy after nine-week implantation.The results further showed that the aluminum-zinc containing magnesium alloys AZ31B provided a slower degradation rate in vivo than the pure magnesium.At the locations where magnesium was resorbed,the deposition of new bone was found.The results indicate that magnesium is biocompatible,osteo-conductive and is a potential material for use as a degradable bone implant.

  3. Barbiturate bearing aroylhydrazine derivatives: Synthesis, NMR investigations, single crystal X-ray studies and biological activity

    Science.gov (United States)

    Giziroglu, Emrah; Sarikurkcu, Cengiz; Aygün, Muhittin; Basbulbul, Gamze; Soyleyici, H. Can; Firinci, Erkan; Kirkan, Bulent; Alkis, Ayse; Saylica, Tayfur; Biyik, Halil

    2016-03-01

    A series of barbituric acid aroylhydrazine derivatives have been prepared from their corresponding 1,3-dimethyl-5-acetyl barbituric acid and aroylhydrazines. All compounds have been fully characterized by using FT-IR, multinuclear NMR (1H, 13C) and Mass (MS) spectrometry. We also describe the X-ray crystal structure of 3a, which crystallizes in the monoclinic P21/n space group. The crystal structure is stabilized with infinite linear chains of dimeric units. Furthermore, all compounds were investigated for their tyrosinase inhibition, antioxidative and antimicrobial activies. The results from biological activity assays have shown that all of compounds have excellent antioxidant, significant tyrosinase inhibition and moderate antimicrobial activity.

  4. Biological agents: investigation into leprosy and other infectious diseases before indication.

    Science.gov (United States)

    Antônio, João Roberto; Soubhia, Rosa Maria Cordeiro; Paschoal, Vania Del Arco; Amarante, Carolina Forte; Travolo, Ana Regina Franchi

    2013-01-01

    Biological agents are widely used for various immune-mediated diseases, with remarkable effectiveness in the treatment of rheumatoid arthritis (RA), psoriasis, psoriatic arthritis, ankylosing spondylitis and Crohn's disease. However, attention needs to be drawn to the adverse effects of these therapies and the risk of reactivating underlying granulomatous infectious diseases such as tuberculosis, leprosy, syphilis, leishmaniasis, among others. The objective of this paper is to describe a case of leprosy in a patient with RA using anti-TNF alfa, demonstrating the need for systematic investigation of skin lesions suggestive of leprosy in patients who require rheumatoid arthritis therapeutic treatment, especially in endemic regions like Brazil. PMID:24346871

  5. Investigations on mechanical biological treatment of waste in South America: Towards more sustainable MSW management strategies

    International Nuclear Information System (INIS)

    This work presents an analysis on the suitability of mechanical biological treatment of municipal solid waste in South America, based on two previous experimental investigations carried out in two different countries. The first experiment was performed for determining the mass and volume reduction of MSW in the province of Concepcion (Chile). The implemented bench-scale process consisted of a manual classification and separation stage, followed by an in-vessel biological degradation process. The second experiment consisted of a full-scale experiment performed in the city of Estrela (Brazil), where the existing municipal waste management facility was adapted to enhance the materials sorting and separation. Expressed in wet weight composition, 85.5% of the material input in the first experiment was separated for biological degradation. After 27 days of processing, 60% of the initial mass was reduced through degradation and water evaporation. The final fraction destined for landfilling equals 59% of the total input mass, corresponding to about 50% of the initial volume. In the second experiment, the fraction destined to landfill reaches 46.6% of the total input waste mass, whilst also significantly reducing the total volume to be disposed. These results, and the possible recovery of material streams suitable for recycling or for preparing solid recovered fuels, are the main advantages of the studied process

  6. The developing strategy of Chinese magnesium and magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    ZUO; Tie-yong; DU; Wen-bo

    2005-01-01

    The status and developing strategy of Chinese magnesium industry are summarized in the present paper. The output and export of Chinese magnesium ingot have rapidly increased in the recent ten years, but the magnesium products with high value, such as the wrought magnesium alloys, and their applications are insufficient. Chinese magnesium industry should develop toward the direction of large scale, specialization and collectivization in the future. The enterprises should enhance the level of management and reinforce the international competing ability with the help of governmental policies.

  7. An Investigation on the Tribological Performances of the SiO2/MoS2 Hybrid Nanofluids for Magnesium Alloy-Steel Contacts

    Science.gov (United States)

    Xie, Hongmei; Jiang, Bin; Liu, Bo; Wang, Qinghang; Xu, Junyao; Pan, Fusheng

    2016-07-01

    Hybrid nano-materials offer potential scope for an increasing numerous novel applications when engineered to deliver availably functional properties. In the present study, the SiO2/MoS2 hybrid nanoparticles with different mass ratios were employed as lubricant additives in the base oil, and their tribological properties were evaluated using a reciprocating ball-on-plate tribometer for magnesium alloy-steel contacts. The results demonstrate that the SiO2/MoS2 hybrid nanoparticles exhibit superior lubrication performances than individual nano-SiO2 or nano-MoS2 even in high load and diverse velocity cases. The optimal SiO2/MoS2 mixing ratio and the concentration of SiO2/MoS2 hybrid nanoparticles in the base oil are 0.25:0.75 and 1.00-1.25 wt%, respectively. The excellent lubrication properties of the SiO2/MoS2 hybrid nanoparticles are attributed to the physical synergistic lubricating actions of nano-SiO2 and nano-MoS2 during the rubbing process.

  8. Biological applications and transmission electron microscopy investigation of mesoporous silica nanoparticles

    Science.gov (United States)

    Trewyn, Brian G.

    The research presented and discussed within involves the development of novel biological applications of mesoporous silica nanoparticles (MSN) and an investigation of mesoporous material by transmission electron microscopy (TEM). A series of room-temperature ionic liquid (RTIL) containing mesoporous silica nanoparticle (MSN) materials with various particle morphologies, including spheres, ellipsoids, rods, and tubes, were synthesized. By changing the RTIL template, the pore morphology was tuned from the MCM-41 type of hexagonal mesopores to rotational moire type of helical channels, and to wormhole-like porous structures. These materials were used as controlled release delivery nanodevices to deliver antibacterial ionic liquids against Escherichia coli K12. The involvement of a specific organosiloxane function group, covalently attached to the exterior of fluorescein doped mesoporous silica nanoparticles (FITC-MSN), on the degree and kinetics of endocytosis in cancer and plant cells was investigated. The kinetics of endocystosis of TEG coated FITC-MSN is significantly quicker than FITC-MSN as determined by flow cytometry experiments. The fluorescence confocal microscopy investigation showed the endocytosis of TEG coated-FITC MSN triethylene glycol grafted fluorescein doped MSN (TEG coated-FITC MSN) into both HeLa cells and Tobacco root protoplasts. Once the synthesis of a controlled-release delivery system based on MCM-41-type mesoporous silica nanorods capped by disulfide bonds with superparamagnetic iron oxide nanoparticles was completed. The material was characterized by general methods and the dosage and kinetics of the antioxidant dependent release was measured. Finally, the biological interaction of the material was determined along with TEM measurements. An electron microscopy investigation proved that the pore openings of the MSN were indeed blocked by the Fe 3O4 nanoparticles. The biological interaction investigation demonstrated Fe3O4-capped MSN

  9. Magnesium and its alloys as degradable biomaterials : Corrosion studies using potentiodynamic and EIS electrochemical techniques

    OpenAIRE

    Wolf Dieter Müller; Maria Lucia Nascimento; Miriam Zeddies; Mariana Córsico; Liliana Mabel Gassa; Mónica Alicia Fernández Lorenzo de Mele

    2007-01-01

    Magnesium is potentially useful for orthopaedic and cardiovascular applications. However, the corrosion rate of this metal is so high that its degradation occurs before the end of the healing process. In industrial media the behaviour of several magnesium alloys have been probed to be better than magnesium performance. However, the information related to their corrosion behaviour in biological media is insufficient. The aim of this work is to study the influence of the components of organic f...

  10. Hydrogenations of alloys and intermetallic compounds of magnesium

    International Nuclear Information System (INIS)

    A kinetic and thermodynamic study of the hydrogenation of alloys and intermetallic compounds of magnesium is presented. It was established that the addition of elements of the IIIA group (Al, Ga, In) to magnesium catalyses its hydrogenation. This is explained by the mechanism of diffusion of magnesium cation vacancies. The hydride Mg2NiH4 was characterized by thermal analysis, x-ray diffraction and NMR measurements. The possibility of forming pseudo-binary compounds of Mg2Ni by the substitution of nickel or magnesium was examined. The hydrogenation of the inter-metallic compounds of the Mg-Al system was investigated. It was found that the addition of indium and nickel affected the hydrogenation kinetics. A preliminary study of the hydrogenation of various binary and ternary alloys of magnesium was carried out. (Author)

  11. Preparation of Magnesium Carbonate Whisker from Magnesite Tailings

    Energy Technology Data Exchange (ETDEWEB)

    Wang, N; Chen, M [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Ni, H W, E-mail: chenm@smm.neu.edu.cn [Wuhan University of Science and Technology, Wuhan 430081 (China)

    2011-10-29

    Magnesium carbonate whisker was prepared by thermal decomposition of Mg(HCO{sub 3}){sub 2} solution that was prepared through hydration and carbonation of light burnt magnesia derived from magnesite tailings. The effects of thermal decomposition conditions on the morphology of magnesium carbonate crystal were investigated. The results showed that thermal decomposition product was MgCO{sub 3{center_dot}}3H{sub 2}O, and its crystal morphology was appreciably influenced by the additives added to Mg(HCO{sub 3}){sub 2} solution. Magnesium carbonate whiskers were successfully prepared when a kind of soluble magnesium salt was added, and magnesium carbonate whiskers with the length of 20 to 60{mu}m and aspect ratio of 10{approx}20 were obtained under the condition of 50deg. C thermal decomposition temperature and 200 rpm stirring intensity.

  12. Twin-roll strip casting of magnesium alloys in China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The development status of twin-roll strip casting for magnesium alloys in China was summarized as well as the new progress when several kinds of twin-roll strip casting technologies were developed and used.Horizontal twin-roll casting (HTRC) of magnesium alloys has attracted much attention and has been industrialized in China.Vertical twin roll casting(VTRC) of the magnesium alloys can reach a speed of higher than 30 m/min and its research and development are just beginning and exhibit exciting potential.By comparing the process characteristics of the two technologies,the process stability of HTRC for the magnesium alloys is better,and the casting speed and the cooling rate of VTRC for the magnesium alloys are higher.The quality of the products by the two technologies needs to be improved and further investigated.

  13. Investigation of biological effects of some Mannich Bases containing Bis-1,2,4- Triazole.

    Science.gov (United States)

    Parlak, A E; Celik, S; Karatepe, M; Turkoglu, S; Alayunt, N O; Dastan, S D; Ulas, M; Sandal, S; Tekin, S; Koparir, M

    2016-01-01

    In this study, the effects of Mannich bases containing bis-1,2,4-triazole on the levels of in vivo malondialdehyde (MDA) and antioxidant vitamins (A, E, C) were examined in serum, livers and kidneys of rats. DA and vitamin (A, E, C) levels were determined by high performance liquid chromatography (HPLC). Antioxidant effect was investigated by determining the MDA levels in Saccharomyces cerevisiae cells as in vitro. Furthermore, the antitumor effects of compounds were investigated against MCF-7 human breast cancer cells. Interrelations of results among control and compound groups were evaluated using SPSS statistical software package. As a result, some of the compounds showed effective biological activity when compared to control conditions. The test compounds used in this study may be effective for utilization in the selection and design of model compounds for further studies. PMID:27453272

  14. Elemental analysis of biological tissues of animal models in muscular dystrophies investigation

    International Nuclear Information System (INIS)

    Element concentrations in biological tissues of Dmdmdx/J and C57BL/6 J mice strains were determined using the neutron activation analysis technique. Samples of whole blood, bones and organs (heart and muscle) of these strains were irradiated in the IEA-R1 nuclear reactor at IPEN-CNEN/SP (Brazil). To perform this investigation biological samples of two-month-old adult females (n = 10) and males (n = 9) for Dmdmdx/J (dystrophic mice), and males (n 12) for C57BL/6 J (control group), originally obtained from the Jackson Laboratory (Maine, USA) and further inbred at IPEN-CNEN/SP (Sao Paulo, Brazil), were used. A significant change was observed in the analysis of the heart of dystrophic mice suggesting that this dysfunction affects severely the heart muscle. These data may, in the future, contribute to the healthcare area, in veterinary medicine and in the pharmaceutical industry allowing the evaluation of the best procedures in diagnosis, treatment and investigations of neuromuscular diseases (muscular dystrophy) of patients through the use of animal models. (author)

  15. Quantitative investigation of a hybrid Ziegler-Natta catalyst support prepared by grafting di(n-butyl)magnesium onto partially dehydroxylated silica.

    Science.gov (United States)

    Lee, Ming-Yung; Scott, Susannah L

    2011-04-11

    MgCl(2)-modified silica is an important component of some Ziegler-Natta catalysts used in the manufacture of polyethylene. Information about the structure of the dispersed magnesium sites formed by the reaction of di-n-butylmagnesium (nBu(2)Mg) with silica was sought to provide a basis for understanding their subsequent interactions with transition-metal or co-catalyst components. From infrared spectra and elemental analysis, we deduced that nBu(2)Mg reacts with porous silica in two ways: about half (47%, 0.99 mmol g(-1)) is grafted through protonolysis by surface hydroxyl groups (≡SiOH), whereas the other half (53%, 1.11 mmol g(-1)) reacts directly with siloxane bonds (≡SiOSi≡). In the (29)Si and (13)C CP/MAS NMR spectra of Sylopol-2100 silica pretreated at 500 °C then modified with nBu(2)Mg at room temperature, both alkylsilicon and alkylmagnesium sites are evident. The alkylmagnesium-modified silica surface is proposed to contain dimers and/or tetramers with the empirical formula [≡SiOMg(nBu)](n). Upon exposure of nBu(2)Mg-modified silica to anhydrous HCl, alkanes are liberated, hydroxyl groups are regenerated, and water is formed. The appearance of water suggests condensation of hydroxyl group pairs, induced by the coordinatively unsaturated nanoclusters (MgCl(2))(n) that arise by ligand exchange on the silica-supported n-butylmagnesium oligomers. PMID:21433118

  16. FOCUS ON MAGNESIUM BASED DRUGS

    Directory of Open Access Journals (Sweden)

    I. I. Esenova

    2016-01-01

    Full Text Available Magnesium deficiency in the organism is one of the most common human deficiency states. The prevalence of magnesium deficiency is about 15%, and suboptimal magnesium level is observed more than in 30% of people in the general population. Clinical signs of hypomagnesaemia are observed in 40% of patients in general care hospitals, in 70% of patients - in intensive care units, and magnesium deficiency occurs in 90% of patients with acute coronary syndrome. Magnesium metabolic disorders in the organism accelerate significantly development of complications of coronary heart disease, hypertension, type 2 diabetes, asthma and a number of neurological and psychiatric diseases. The value of this macro in the body is well studied, and its daily need is identified depending on age and sex. It is known that magnesium intake with the food does not cover an organism need. It is a rationale for preventive and therapeutic use of magnesium based drugs in various diseases. Organic salts of magnesium are recommended for these purposes. Magnesium metabolic disorders, approaches to pharmacotherapeutic correction of magnesium deficiency, advantages of magnesium salts of orotic acid are reviewed.

  17. Design considerations for developing biodegradable and bioabsorbable magnesium implants

    Science.gov (United States)

    Brar, Harpreet S.; Keselowsky, Benjamin G.; Sarntinoranont, Malisa; Manuel, Michele V.

    2011-04-01

    The integration of biodegradable and bioabsorbable magnesium implants into the human body is a complex undertaking that faces major challenges. Candidate biomaterials must meet both engineering and physiological requirements to ensure the desired properties. Historically, efforts have been focused on the behavior of commercial magnesium alloys in biological environments and their resultant effect on cell-mediated processes. Developing causal relationships between alloy chemistry and microstructure, and effects as a cellular behavior can be a difficult and time-intensive process. A systems design approach has the power to provide significant contributions in the development of the next generation of magnesium alloy implants with controlled degradability, biocompatibility, and optimized mechanical properties, at reduced time and cost. This approach couples experimental research with theory and mechanistic modeling for the accelerated development of materials. The aim of this article is to enumerate this strategy, design considerations, and hurdles for developing new cast magnesium alloys for use as biodegradable implant materials.

  18. Serum Magnesium Concentration Is Inversely Associated with Albuminuria and Retinopathy among Patients with Diabetes

    Science.gov (United States)

    Lu, Jun; Gu, Yuying; Guo, Meixiang; Chen, Peihong; Wang, Hongtao

    2016-01-01

    Aim. To investigate the association between serum magnesium levels and microvascular complications among patients with diabetes. Methods. Patients with diabetes were recruited between April 2012 and January 2015. All patients received an assay of serum magnesium concentration, were screened for 24 h albumin excretion rate, and underwent nonmydriatic fundus photography. Albuminuria and retinopathy were defined accordingly. A total of 3,100 patients with normal serum magnesium levels were included in this study. Results. Patients with albuminuria and/or retinopathy had lower levels of serum magnesium than patients without these complications (P diabetic microvascular complications among patients with serum magnesium levels within the normal range.

  19. Isotopic tracer method in the investigation of the scraper work in the clarifier of the biological sewage-treatment plant

    International Nuclear Information System (INIS)

    A method of investigation of the velocity of sediment transport in a clarifier of the biological sewage- treatment plant is described. It is based on the tracking of the motion of sediment portion containing 32P or 140La. (author)

  20. Magnesium and Boron Combustion in Hot Steam Atmosphere

    OpenAIRE

    V. Rosenband; A. Gany; Timnat, Y.M.

    1998-01-01

    This paper investigates the combustion of magnesium and boron powders in hot steam. A thermochemical analysis reveals theoretical results of such interactions. An experimental investigation demonstrates that stable exothermic oxidation takes place, resulting in actual combustion at 1100 °c for magnesium and 800 °c for boron. The reaction generates large quantity of gaseous products consisting of almost pure hydrogen and corresponding to about 60 per cent of a complete chemical reaction

  1. Magnesium and Boron Combustion in Hot Steam Atmosphere

    Directory of Open Access Journals (Sweden)

    V. Rosenband

    1998-07-01

    Full Text Available This paper investigates the combustion of magnesium and boron powders in hot steam. A thermochemical analysis reveals theoretical results of such interactions. An experimental investigation demonstrates that stable exothermic oxidation takes place, resulting in actual combustion at 1100 °c for magnesium and 800 °c for boron. The reaction generates large quantity of gaseous products consisting of almost pure hydrogen and corresponding to about 60 per cent of a complete chemical reaction

  2. Application of Glow Discharge Aes for Investigation of Metal Ions and Water in Biology and Medicine

    CERN Document Server

    Bregadze, Vasil G; Tsakadze, Ketevan J

    2007-01-01

    AES VHF inductively coupled plasmatron may be applied to wide range of studies. It enables rapid microanalysis of various solutions including biological objects and peripheral blood serum. In addition, it may be used for investigation of water desorption from solid bodies and for determination of energetic metal-macromolecule complexes. Study of hydration energy and hydration number by kinetic curves of water glow discharge atomic spectral analysis of hydrogen (GD EAS analysis of hydrogen) desorption from Na-DNA humidified fibers allowed to reveal that structural and conformational changes in activation energy of hydrated water molecules increases by 0.65kcal/Mole of water. The developed method of analysis of elements in solutions containing high concentrations of organic materials allows systematic study of practically healthy persons and reveals risk factors for several diseases. Microelemental content of blood serum fractions showed that amount of not bounded with ceruloplasmin copper was three times more ...

  3. Mechanisms and regulation of renal magnesium transport.

    Science.gov (United States)

    Houillier, Pascal

    2014-01-01

    Magnesium's most important role is in the release of chemical energy. Although most magnesium is stored outside of the extracellular fluid compartment, the regulated value is blood magnesium concentration. Cellular magnesium and bone magnesium do not play a major role in the defense of blood magnesium concentration; the major role is played by the kidney, where the renal tubule matches the urinary magnesium excretion and the net entry of magnesium into the extracellular fluid. In the kidney, magnesium is reabsorbed in the proximal tubule, the thick ascending limb of the loop of Henle, and the distal convoluted tubule. Magnesium absorption is mainly paracellular in the proximal tubule and in the thick ascending limb of the loop of Henle, whereas it is transcellular in the distal convoluted tubule. Several hormones and extracellular magnesium itself alter the distal tubular handling of magnesium, but the hormone(s) regulating extracellular magnesium concentration remains unknown. PMID:24512082

  4. Magnesium for Hydrogen Storage

    DEFF Research Database (Denmark)

    Pedersen, Allan Schrøder; Kjøller, John; Larsen, B.;

    1983-01-01

    A study of the hydrogenation characteristics of fine magnesium powder during repeated cycling has been performed using a high-pressure microbalance facility. No effect was found from the cycling regarding kinetics and storage capacity. The reaction rate of the absorption process was fast at tempe......A study of the hydrogenation characteristics of fine magnesium powder during repeated cycling has been performed using a high-pressure microbalance facility. No effect was found from the cycling regarding kinetics and storage capacity. The reaction rate of the absorption process was fast...... at temperatures around 600 K and above, but the reversed reaction showed somewhat slower kinetics around 600 K. At higher temperatures the opposite was found. The enthalpy and entropy change by the hydrogenation, derived from pressure-concentration isotherms, agree fairly well with those reported earlier....

  5. Mineral of the month: magnesium

    Science.gov (United States)

    Kramer, Deborah A.

    2005-01-01

    Magnesium, often confused with last month’s mineral of the month manganese, is valued primarily because of its light weight and high strength-to-weight ratio. Magnesium is the eighth most abundant element and constitutes about 2 percent of the Earth’s crust. It is the third most plentiful element dissolved in seawater, with a concentration averaging 0.13 percent. Magnesium is found in over 60 minerals, and also is recovered from seawater, wells, and lake brines and bitterns.

  6. Low brain magnesium in migraine

    International Nuclear Information System (INIS)

    Brain magnesium was measured in migraine patients and control subjects using in vivo 31-Phosphorus Nuclear Magnetic Resonance Spectroscopy. pMg and pH were calculated from the chemical shifts between Pi, PCr and ATP signals. Magnesium levels were low during a migraine attack without changes in pH. We hypothesize that low brain magnesium is an important factor in the mechanism of the migraine attack

  7. Sol - Gel synthesis and characterization of magnesium peroxide nanoparticles

    Science.gov (United States)

    Jaison, J.; Ashok raja, C.; Balakumar, S.; Chan, Y. S.

    2015-04-01

    Magnesium peroxide is an excellent source of oxygen in agriculture applications, for instance it is used in waste management as a material for soil bioremediation to remove contaminants from polluted underground water, biological wastes treatment to break down hydrocarbon, etc. In the present study, sol-gel synthesis of magnesium peroxide (MgO2) nanoparticles is reported. Magnesium peroxide is odourless; fine peroxide which releases oxygen when reacts with water. During the sol-gel synthesis, the magnesium malonate intermediate is formed which was then calcinated to obtain MgO2 nanoparticles. The synthesized nanoparticles were characterized using Thermo gravimetric -Differential Thermal Analysis (TG- DTA), X-Ray Diffraction studies (XRD) and High Resolution Transmission Electron Microscope (HRTEM). Our study provides a clear insight that the formation of magnesium malonate during the synthesis was due to the reaction between magnesium acetate, oxalic acid and ethanol. In our study, we can conclude that the calcination temperature has a strong influence on particle size, morphology, monodispersity and the chemistry of the particles.

  8. 76 FR 33194 - Pure Magnesium From the People's Republic of China: Preliminary Results of the 2009-2010...

    Science.gov (United States)

    2011-06-08

    ... Fair Value: Antidumping Duty Investigation of Pure Magnesium From the Russian Federation, 60 FR 25691... Antidumping Duty Administrative Review, 73 FR 76336 (December 16, 2008)(``Pure Magnesium 06-07''); and... FR 76336 (December 16, 2008) and accompanying IDM (``2006-2007 Pure Magnesium Review'')...

  9. Reprint of: The history of biodegradable magnesium implants: A review.

    Science.gov (United States)

    Witte, Frank

    2015-09-01

    Today, more than 200 years after the first production of metallic magnesium by Sir Humphry Davy in 1808, biodegradable magnesium-based metal implants are currently breaking the paradigm in biomaterial science to develop only highly corrosion resistant metals. This groundbreaking approach to temporary metallic implants is one of the latest developments in biomaterials science that is being rediscovered. It is a challenging topic, and several secrets still remain that might revolutionize various biomedical implants currently in clinical use. Magnesium alloys were investigated as implant materials long ago. A very early clinical report was given in 1878 by the physician Edward C. Huse. He used magnesium wires as ligature for bleeding vessels. Magnesium alloys for clinical use were explored during the last two centuries mainly by surgeons with various clinical backgrounds, such as cardiovascular, musculoskeletal and general surgery. Nearly all patients benefited from the treatment with magnesium implants. Although most patients experienced subcutaneous gas cavities caused by rapid implant corrosion, most patients had no pain and almost no infections were observed during the postoperative follow-up. This review critically summarizes the in vitro and in vivo knowledge and experience that has been reported on the use of magnesium and its alloys to advance the field of biodegradable metals. PMID:26235343

  10. Influence of Magnesium Alloy Degradation on Undifferentiated Human Cells

    OpenAIRE

    Francesca Cecchinato; Nezha Ahmad Agha; Adela Helvia Martinez-Sanchez; Berengere Julie Christine Luthringer; Frank Feyerabend; Ryo Jimbo; Regine Willumeit-Römer; Ann Wennerberg

    2015-01-01

    Background Magnesium alloys are of particular interest in medical science since they provide compatible mechanical properties with those of the cortical bone and, depending on the alloying elements, they have the capability to tailor the degradation rate in physiological conditions, providing alternative bioresorbable materials for bone applications. The present study investigates the in vitro short-term response of human undifferentiated cells on three magnesium alloys and high-purity magnes...

  11. Microstructure and kinetics of hot deformation WE43 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    GAO Jiacheng; WANG Qiang; WANG Yong; LI Wei; NIU Wenjuan

    2008-01-01

    The effect of compression on the rnicrostructures and flow behavior of WE43 magnesium alloy was investigated in this article.The relationship between flow stress and strain rate was discussed.According to the empirical formula ε = Aσn exp(-Q/RT),the value of heat activation of WFA3 magnesium alloys is 297.15 kJ/mol.A mechanism of deformation softening of WEA3 alloy in testing hot deformation was identified to be dynamic recrystallization.

  12. Marine resources chemistry of magnesium. Magnesium no kaiyo shigen kagaku

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-18

    Marine water body covers 71% of the earth surface, and has an average depth of about 3700 m. This huge marine water body contains magnesium of 1300 ppm on average in its water. This paper describes research and development related to high-purity sea water magnesium oxide that could be produced from these marine resources. Effects of impurities in sea water, particularly removal of calcium and boron are the important subject for studying high-purity sea water magnesium oxide. This paper describes results of developing a decarbonation pretreatment method for reducing calcium impurities and an alkaline method to reduce boron impurities. Most methods of manufacturing magnesium from sea water in an industrial scale change magnesium hydroxide precipitated from sea water into MgCl2, and electrolyze it to obtain metallic magnesium. The paper shows results of the development of a method to recover magnesium hydroxide and basic magnesium carbonate using the lime-ammonium circulation process that uses salt making bittern as a raw material. 6 refs., 7 figs.

  13. In situ investigations of biological molecules using vibrational sum-frequency-generation spectroscopy

    OpenAIRE

    Howell, Caitlin

    2011-01-01

    The molecular-level understanding of biological molecules on solid surfaces is critical in areas including medicine, biologically-based industry, and the development of biotechnologies. In order to gain further knowledge of the orientation and organization of biological molecules adsorbed on surfaces, we used the label-free, interface-specific technique of sum-frequency generation (SFG) spectroscopy. This technique has the distinct advantage of being able to be operated in situ as well as ex ...

  14. Investigation of furfural biodegradation in a continuous inflow cyclic biological reactor.

    Science.gov (United States)

    Moussavi, Gholamreza; Leili, Mostafa; Nadafi, Kazem

    2016-01-01

    The performance of a continuous inflow cyclic biological reactor (CBR) containing moving media was investigated for the degradation of high concentrations of furfural. The effects of hydraulic retention time (HRT) and furfural initial concentrations (loading rate), as main operating parameters, on the bioreactor performance were studied. The results indicated that the CBR could remove over 98% of furfural and 71% of its chemical oxygen demand (COD) at inlet furfural concentrations up to 1,200 mg L(-1) (2.38 g L(-1) d(-1)), a 6-h cycle time and HRT of 12.1 h. The removal efficiency decreased slightly from 98 to 94% when HRT decreased from 12.1 to 10.5 h. The average removal efficiency of furfural and COD during the 345-day operational period under steady-state conditions were 97.7% and 82.1%, respectively. The efficiency also increased approximately 17.2% after addition of synthetic polyurethane cubes as moving media at a filling ratio of 10%. PMID:26819384

  15. Investigation of the biological shielding properties of ferruginous and sandy clays

    International Nuclear Information System (INIS)

    The biological shielding properties of two local clays, the ferruginous clay from Nsaba and the sandy clay from Winneba, at three different firing temperatures (9500C, 10000C and 11000C) have been investigated. The attenuation coefficient and hence the half-value-layers for different gamma energies determined revealed that Portland concrete is better than the clays for lower gamma energies but the reverse is true for high energy gammas. The diffusion lengths of thermal neutrons in the clays were observed to be relatively shorter than the 6.61 cm recorded for Portland concrete. The worst value obtained being 1.81 cm. There is the possibility of improving on the shielding properties of the clays by adding boron or cadmium and firing below 444.60C in the former and 746.40C in the latter or by hand pressing during moulding to reduce the porosity. The values of the moduli of rupture indicates their general weakness in comparison with concrete but again it is believed that hand pressed bricks would be stronger. (author)

  16. Structural Investigation of Biological and Semiconductor Nanostructures with Nonlinear Multicontrast Microscopy

    Science.gov (United States)

    Cisek, Richard

    Physical and functional properties of advanced nano-composite materials and biological structures are determined by self-organized atoms and molecules into nanostructures and in turn by microscopic organization of the nanostructures into assemblies of higher structural complexity. Therefore, microscopes are indispensable tools for structural investigations at various levels of organization. In this work, novel nonlinear optical microscopy methods were developed to non-invasively study structural organization at the nanoscopic and microscopic levels. Atomic organization of semiconductor nanowires, molecular organization of amylose biocrystallites in starch granules, and microscopic organization of several photosynthetic organisms was elucidated. The structure of ZnSe nanowires, key components in many modern nanodevices, was investigated using polarization harmonic generation microscopy. Based on nonlinear optical properties of the different crystal lattices, zinc blende and wurtzite nanowires were differentiated, and the three-dimensional orientation of the zinc blende nanowires could be found. The structure of starch granules, a model biocrystal, important in food as well as health sciences, was also investigated using polarization harmonic microscopy. The study was combined with ab initio calculations using the crystal structures of amylose A and B, revealing that second harmonic signals originate from the hydroxide and hydrogen bonds in the starch granules. Visualization of several photosynthetic organisms including the green algae, Chlamydomonas reinhardtii, two species of cyanobacteria, Leptolyngbya sp. and Anabaena sp., aggregates of light-harvesting pigment-protein complexes as well as chloroplasts from green plants were also explored, revealing that future nonlinear microscopy applications could include structural studies of cell walls, the Chlamydomonas eyespot, and photosynthetic membranes. In this study, several nonlinear optical microscopy modalities

  17. Application of recovered magnesium hydroxide from a flue gas desulfurization system for wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, P.L.; Wu, Q.; Keener, T.; Zhuang, L.A.; Gurusamy, R.; Pehkonen, S.

    1999-07-01

    Magnesium hydroxide, reclaimed from the flue gas desulfurization system (FGD) at the Zimmer Power Plant, Cincinnati, Ohio, is a weak base, in the form of either a slurry or powder. It has many potential applications for wastewater treatment. The objectives of this research are (1) to characterize the reclaimed magnesium hydroxide, e.g., purity, particle size distribution, dissolution kinetics; (2) to evaluate neutralization capacity and buffering intensity of the reclaimed magnesium hydroxide; (3) to study the efficacy of the reclaimed magnesium hydroxide for nutrient removal in wastewater treatment processes; (4) to investigate whether and how the magnesium hydroxide influences the characteristics of the activated sludge floc; (5) to determine whether magnesium hydroxide improves the anaerobic sludge digestion process and associated mechanisms; and (6) to conduct a cost-benefit analysis for the application of the reclaimed magnesium hydroxide in wastewater treatment and the possibility of marketing this product. Research results to date show that the purity of the reclaimed magnesium hydroxide depends largely on the recovery hydroxide slurry. This product proved to be very effective for wastewater neutralization, compared with other commonly used chemicals, both for its neutralization capacity and its buffering intensity. Due to its relatively low solubility in water and its particle size distribution characteristics, magnesium hydroxide behaves like a weak base, which will be very beneficial for process control. The authors also found that nitrogen and phosphorus could be removed from the wastewater using magnesium hydroxide due to their complexation and precipitation as magnesium ammonium phosphate (struvite). Magnesium hydroxide also greatly enhanced the settleability of the activated sludge. Intensive research on the mechanisms associated with these phenomena reveals that sweep flocculation and magnesium ion bridging between exopolymeric substances (EPS) of

  18. Magnesium Hall Thruster

    Science.gov (United States)

    Szabo, James J.

    2015-01-01

    This Phase II project is developing a magnesium (Mg) Hall effect thruster system that would open the door for in situ resource utilization (ISRU)-based solar system exploration. Magnesium is light and easy to ionize. For a Mars- Earth transfer, the propellant mass savings with respect to a xenon Hall effect thruster (HET) system are enormous. Magnesium also can be combusted in a rocket with carbon dioxide (CO2) or water (H2O), enabling a multimode propulsion system with propellant sharing and ISRU. In the near term, CO2 and H2O would be collected in situ on Mars or the moon. In the far term, Mg itself would be collected from Martian and lunar regolith. In Phase I, an integrated, medium-power (1- to 3-kW) Mg HET system was developed and tested. Controlled, steady operation at constant voltage and power was demonstrated. Preliminary measurements indicate a specific impulse (Isp) greater than 4,000 s was achieved at a discharge potential of 400 V. The feasibility of delivering fluidized Mg powder to a medium- or high-power thruster also was demonstrated. Phase II of the project evaluated the performance of an integrated, highpower Mg Hall thruster system in a relevant space environment. Researchers improved the medium power thruster system and characterized it in detail. Researchers also designed and built a high-power (8- to 20-kW) Mg HET. A fluidized powder feed system supporting the high-power thruster was built and delivered to Busek Company, Inc.

  19. First-Year Biology Students' Understandings of Meiosis: An Investigation Using a Structural Theoretical Framework

    Science.gov (United States)

    Quinn, Frances; Pegg, John; Panizzon, Debra

    2009-01-01

    Meiosis is a biological concept that is both complex and important for students to learn. This study aims to explore first-year biology students' explanations of the process of meiosis, using an explicit theoretical framework provided by the Structure of the Observed Learning Outcome (SOLO) model. The research was based on responses of 334…

  20. An Investigation of the Relative Effectiveness of Two Scheduling Patterns of an Introductory College Biology Course.

    Science.gov (United States)

    Chanin, Lynne Sheppard

    Students in an introductory biology course had laboratory sessions in one of two patterns: as one three-hour session per week, or as two one-and-one-half hour sessions, one after each lecture. Each of the twelve instructors involved taught one section using each pattern. The Nelson Biology Test, the Watson-Glaser Critical Thinking Appraisal, and a…

  1. Photon activation method to the investigation of bioobjects content for juridical-biological examination

    International Nuclear Information System (INIS)

    Possibilities of the use of nuclear-physical methods for definition of element composition of biological objects (hair of animals) with the target of receipt of additional evidentiary information at the decision of diagnostics and identification problems within the limits of forensic-biological examination are shown

  2. Topologically ordered magnesium-biopolymer hybrid composite structures.

    Science.gov (United States)

    Oosterbeek, Reece N; Seal, Christopher K; Staiger, Mark P; Hyland, Margaret M

    2015-01-01

    Magnesium and its alloys are intriguing as possible biodegradable biomaterials due to their unique combination of biodegradability and high specific mechanical properties. However, uncontrolled biodegradation of magnesium during implantation remains a major challenge in spite of the use of alloying and protective coatings. In this study, a hybrid composite structure of magnesium metal and a biopolymer was fabricated as an alternative approach to control the corrosion rate of magnesium. A multistep process that combines metal foam production and injection molding was developed to create a hybrid composite structure that is topologically ordered in all three dimensions. Preliminary investigations of the mechanical properties and corrosion behavior exhibited by the hybrid Mg-polymer composite structures suggest a new potential approach to the development of Mg-based biomedical devices. PMID:24659540

  3. Magnesium in Prevention and Therapy

    Science.gov (United States)

    Gröber, Uwe; Schmidt, Joachim; Kisters, Klaus

    2015-01-01

    Magnesium is the fourth most abundant mineral in the body. It has been recognized as a cofactor for more than 300 enzymatic reactions, where it is crucial for adenosine triphosphate (ATP) metabolism. Magnesium is required for DNA and RNA synthesis, reproduction, and protein synthesis. Moreover, magnesium is essential for the regulation of muscular contraction, blood pressure, insulin metabolism, cardiac excitability, vasomotor tone, nerve transmission and neuromuscular conduction. Imbalances in magnesium status—primarily hypomagnesemia as it is seen more common than hypermagnesemia—might result in unwanted neuromuscular, cardiac or nervous disorders. Based on magnesium’s many functions within the human body, it plays an important role in prevention and treatment of many diseases. Low levels of magnesium have been associated with a number of chronic diseases, such as Alzheimer’s disease, insulin resistance and type-2 diabetes mellitus, hypertension, cardiovascular disease (e.g., stroke), migraine headaches, and attention deficit hyperactivity disorder (ADHD). PMID:26404370

  4. Serum Copper, Zinc And Magnesium Levels in Children with Various Malignant Disorders

    Directory of Open Access Journals (Sweden)

    Atila Tanyeli

    2013-08-01

    Full Text Available Introduction: The minute amounts of several trace elements including copper, zinc and magnesium play some roles as essential constituents of various biological organs. The serum concentrations these elements are modified in some malignancies. The aim of this study is to investigate the copper, zinc and magnesium levels in the serum of children with various malignant disorders. Material and Methods: The serum levels of copper, zinc and magnesium were measured in 82 children with various malignant disorders and in 21 age-matched healty controls using an atomic absorbtion spectrophotometer. Results: The serum Cu, Zn and Mg concentrations were significantly higher than matched control values among patients with acute lymphoblastic leukemia (ALL (p<0.05, p<0.05, p<0.0001, respectively on the other hand, the serum Mg concentrations were also significantly higher than matched control values among patients with acute nonlymphocytic leukemia (ANLL and other solid tumors (p<0.0001, p<0.0001, respectively whereas there were no significant differences in serum Cu and Zn concentrations between healthy controls and in patients ANLL and other solid tumors. (p<0.05, p<0.05 Additionally the copper /zinc ratio in patients with acute lymphoblastic leukemia was significantly higher than the control value whereas a nonsignificant difference was found between healty controls and patients with ANLL and other solid tumors. Conclusion: Trace elements particularly copper and magnesium appear to be elevated in malignant diseases. Such elevation may prove to be useful markers to screen for and perhaps monitor relapse of malignant disease. [Cukurova Med J 2013; 38(4.000: 587-591

  5. Preparation, Spectroscopic Investigation and Biological Activity of New Mixed Ligand Chelates

    International Nuclear Information System (INIS)

    Preparation and investigation of new Co(II), Ni(II), Zn(II) and Cr(III) chelates with mixed ligands including Schiff base (L1) formed from the condensation of 4-dimethylaminobenzaldehyde with 2-aminophenol and anthranilic acid (L2) were studied. The obtained Schiff base and mixed ligand chelates were subjected to several physiochemical techniques, in terms of CHN elemental analyses, molar conductivity, magnetic moment measurements, infrared, proton nuclear magnetic resonance, electronic and mass spectra. The analytical data showed the formation of the Schiff base compound and the ratio of metal to ligands of the chelates are 1:1:1(M:L1:L2). The infrared spectral data exhibited that the used ligands behaving as bidentate ligands towards the metal ions. The proton nuclear magnetic resonance spectral data showed the signals of the active groups in the ligands which entered in chelation with Zn(II) metal ion. The electronic spectral results showed the existence of pie (phenyl ring) and n = pie (C=N) of the ligands and suggested the geometrical structures of the chelates. Meanwhile, the mass spectral data revealed the fragmentations of the Schiff base, anthranilic acid and their Ni(II) mixed ligand chelate has been preformed the only chelate conducted for justification. All the prepared mixed chelates were non-electrolyte in nature. The antibacterial activity of the Schiff base, anthranilic acid, metal salts and mixed ligand chelates were studied and found to be that mixed ligand chelates have the most biological activity in comparison to the free ligands and salts. (author)

  6. Zanthoxylum caribaeum (Rutaceae) essential oil: chemical investigation and biological effects on Rhodnius prolixus nymph.

    Science.gov (United States)

    Nogueira, J; Mourão, S C; Dolabela, I B; Santos, M G; Mello, C B; Kelecom, A; Mexas, R; Feder, D; Fernandes, C P; Gonzalez, M S; Rocha, L

    2014-11-01

    A chemical investigation and bioassays against fifth-instar nymphae of the hematophagous insect Rhodnius prolixus, vector of Chagas disease, were conducted with the essential oil from Zanthoxylum caribaeum. The main results may be summarized as follows: (i) 54 components were identified, corresponding to 90.4% of the relative composition; sesquiterpenes (47.3%) and monoterpenes (41.2%) are the major constituents; (ii) muurola-4,5-trans-diene and isodaucene are described for the first time as chemical constituents of the essential oil from leaves of this species; (iii) topical treatment with the crude essential oil induced high levels of paralysis (from 18.88 to 33.33%) and mortality (from 80 to 98.9%) depending on the dose applied (0.5 to 5.0 μl per insect); (iv) feeding treatment with the crude essential oil also induced high levels of mortality (from 48.8 to 100%) but low levels of paralysis (from 2.22 to 7.77%) depending on the dose applied (0.5 to 5.0 μl/ml of blood); (v) in the continuous treatment, only the dose of 5.0 μl/cm(2) was able to promote statistical significant levels of mortality (63.3%) but no paralysis were detected. However in this group, occasionally, only few insects displayed malformations of legs and wings after treatment; and (vi) any treatment was able to disrupt the metamorphosis process since the low adult stage emergence observed to all groups was due the high insect mortality. These observations suggest the interference of Z. caribaeum compounds on the triatomine neuroendocrine system. The significance of these results in relation to the relevant biological events in R. prolixus as well as the possible use of insect growth regulators present in Z. caribaeum oil in integrated vector control programs against hematophagous triatomine species is herein discussed. PMID:25224729

  7. Dynamic behaviors of a Ca–P coated AZ31B magnesium alloy during in vitro and in vivo degradations

    International Nuclear Information System (INIS)

    Surface modification can be an effective way to control the biodegradation behavior of magnesium alloys and even improve their biological properties. Much attention has been paid to the initial protection ability and biological properties of magnesium alloys coating. In this work, the dynamic behaviors of a Ca–P coated AZ31B magnesium alloy during the degradations in vitro and in vivo, including hemolysis, mechanical loading capability and implantation in animals, were investigated. The hemolytic rates of the alloy with and without coating were all declined to be lower than 5% after more than 20 days immersion in PBS, though an increase happened to the alloy at the early immersion of 3–7 days. Reduction of the mechanical loading capacity was gradually evolved for the coated alloy and the peak load retention of 85% was still maintained after 120 days degradation. The in vivo implantation indicated that the Ca–P coated AZ31B alloy showed a more suitable time dependent degradation behavior which was favorable for growth of the new tissue and the healing dynamics of bones, making it a promising choice for medical application.

  8. The Degradation Interface of Magnesium Based Alloys in Direct Contact with Human Primary Osteoblast Cells

    OpenAIRE

    Ahmad Agha, Nezha; Willumeit-Römer, Regine; Laipple, Daniel; Luthringer, Bérengère; Feyerabend, Frank

    2016-01-01

    Magnesium alloys have been identified as a new generation material of orthopaedic implants. In vitro setups mimicking physiological conditions are promising for material / degradation analysis prior to in vivo studies however the direct influence of cell on the degradation mechanism has never been investigated. For the first time, the direct, active, influence of human primary osteoblasts on magnesium-based materials (pure magnesium, Mg-2Ag and Mg-10Gd alloys) is studied for up to 14 days. Se...

  9. Low temperature synthesis of magnesium oxide and spinel powders by a sol-gel process

    OpenAIRE

    Li-Zhai Pei; Wan-Yun Yin; Ji-Fen Wang; Jun Chen; Chuan-Gang Fan; Qian-Feng Zhang

    2010-01-01

    Magnesium oxide and magnesium aluminate (MgAl2O4) spinel (MAS) powders have been synthesized by a simple aqueous sol-gel process using citrate polymeric precursors derived from magnesium chloride, aluminium nitrate and citrate. The thermal decomposition of the precursors and subsequent formation of cubic MgO and MAS were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry-differential scanning calorimetry (TG-DSC) and Fourier transform infrared spectr...

  10. The Synthesis and Physical Properties of Magnesium Borate Mineral of Admontite Synthesized from Sodium Borates

    OpenAIRE

    2014-01-01

    Magnesium borates are significant compounds due to their advanced mechanical and thermal durability properties. This group of minerals can be used in ceramic industry, in detergent industry, and as neutron shielding material, phosphor of thermoluminescence by dint of their extraordinary specialties. In the present study, the synthesis of magnesium borate via hydrothermal method from sodium borates and physical properties of synthesized magnesium borate minerals were investigated. The characte...

  11. Effects of Antenatal Magnesium Exposure on Intestinal Blood Flow and Outcome in Preterm Neonates

    OpenAIRE

    Gürsoy, Tuğba; İmamoğlu, Ebru Yalın; Ovalı, Fahri; Karatekin, Güner

    2015-01-01

    Objective This study aims to investigate the effects of antenatal magnesium sulfate on intestinal blood flow in preterm neonates. Study Design In this prospective case-match study, 25 preterm neonates exposed to magnesium sulfate antenatally were included (study group). Overall, 25 gestational age-matched neonates who had no exposure to magnesium constituted the control group. Serial daily Doppler flow measurements of superior mesenteric artery (SMA) were performed. The time to reach full fee...

  12. Synthesis, aggregation and spectroscopic studies of novel water soluble metal free, zinc, copper and magnesium phthalocyanines and investigation of their anti-bacterial properties

    Science.gov (United States)

    Bayrak, Rıza; Akçay, Hakkı Türker; Beriş, Fatih Şaban; Şahin, Ertan; Bayrak, Hacer; Demirbaş, Ümit

    2014-12-01

    In this study, novel phthalonitrile derivative (3) was synthesized by the reaction between 4-nitrophthalonitrile (2) and a triazole derivative (1) containing pyridine moiety. Crystal structure of compound (3) was characterized by X-ray diffraction. New metal free and metallo-phthalocyanine complexes (Zn, Cu, and Mg) were synthesized using the phthalonitrile derivative (3). Cationic derivatives of these phthalocyanines (5, 7, 9, and 11) were prepared from the non-ionic phthalocyanines (4, 6, 8, and 10). All proposed structures were supported by instrumental methods. The aggregation behaviors of the phthalocyanines (4-11) were investigated in different solvents such as dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), chloroform and water. Water soluble cationic Pcs (5, 7, 9, and 11) aggregated in water and sodium dodecyl sulfate was used to prevent the aggregation. The second derivatives of the UV-Vis spectra of aggregated Pcs were used for analyzing the Q and B bands of aggregated species. Thermal behaviors of the phthalocyanines were also studied. In addition, anti-bacterial properties of the phthalocyanines were investigated. We used four gram negative and two gram positive bacteria to determine antibacterial activity of these compounds. Compound 7 has the best activity against the all bacteria with 125 μg/mL of MIC value. Compounds 4, 6, and 10 have the similar effect on the bacteria with 250 μg/mL of MIC value.

  13. PET Radiochemistry for the Investigation of the biology of pain and inflammation

    OpenAIRE

    Fairclough, Michael Edward

    2015-01-01

    Positron emission tomography (PET) is an important and powerful nuclear imaging modality and is essential in a range of medical fields. A suitable radiotracer must be identified in order for PET imaging to provide high quality and quantifiable data about the pathology. This includes the design and implementation of optimal radiochemistry that will reliably deliver the radiotracer that can answer the pertinent biological questions being asked. PET can be used to study the biological processes ...

  14. Developing Information Fluency in Introductory Biology Students in the Context of an Investigative Laboratory

    OpenAIRE

    Lindquester, Gary J.; Burks, Romi L.; Jaslow, Carolyn R.

    2005-01-01

    Students of biology must learn the scientific method for generating information in the field. Concurrently, they should learn how information is reported and accessed. We developed a progressive set of exercises for the undergraduate introductory biology laboratory that combine these objectives. Pre- and postassessments of approximately 100 students suggest that increases occurred, some statistically significant, in the number of students using various library-related resources, in the number...

  15. Ultrasound-assisted synthesis of magnesium hydroxide nanoparticles from magnesium.

    Science.gov (United States)

    Baidukova, Olga; Skorb, Ekaterina V

    2016-07-01

    Acoustic cavitation in water provides special kinetic and thermodynamic conditions for chemical synthesis and nanostructuring of solids. Using cavitation phenomenon, we obtained magnesium hydroxide from pure magnesium. This approach allows magnesium hydroxide to be synthesized without the requirement of any additives and non-aqueous solvents. Variation of sonochemical parameters enabled a total transformation of the metal to nanosized brucite with distinct morphology. Special attention is given to the obtaining of platelet-shaped, nanometric and de-agglomerated powders. The products of the synthesis were characterized by transmission electron microscopy (TEM), electron diffraction (ED), scanning electron microscopy (SEM) and X-ray diffraction (XRD). PMID:26964968

  16. On the capability of in-situ exposure in an environmental scanning electron microscope for investigating the atmospheric corrosion of magnesium.

    Science.gov (United States)

    Esmaily, M; Mortazavi, N; Shahabi-Navid, M; Svensson, J E; Johansson, L G; Halvarsson, M

    2015-06-01

    The feasibility of environmental scanning electron microscope (ESEM) in studying the atmospheric corrosion behavior of 99.97% Mg was investigated. For reference, ex-situ exposure was performed. A model system was designed by spraying few salt particles on the metal surface and further promoting the corrosion process using platinum (Pt) deposition in the form of 1×1×1 µm(3) dots around the salt particles to create strong artificial cathodic sites. The results showed that the electron beam play a significant role in the corrosion process of scanned regions. This was attributed to the irradiation damage occurring on the metal surface during the ESEM in-situ experiment. After achieving to a reliable process route, in a successful attempt, the morphology and composition of the corrosion products formed in-situ in the ESEM were in agreement with those of the sample exposed ex-situ. PMID:25731810

  17. Vibrational study of magnesium complexes and porphyrins

    International Nuclear Information System (INIS)

    In the course of chlorophyll investigations by vibrational spectroscopy, the magnesium complex Mg(NH3)6Cl2 was studied by infrared and Raman techniques and two porphyrin molecules, by resonance Raman scattering. For the hexa-ammine magnesium chloride, all vibrations predicted by group theory (internal and external vibrations) were observed; ligand orientations gives- the complex ion a D3d point group symmetry. Five isotopically substituted compounds were studied and a force constant calculation showed that the Mg-N bond has a value higher than most of those calculated for other divalent hexa-ammine metal ions. Two porphyrins were studied: the prophine and the meso-porphyrin IX dimethyl-ester.' Unexpected variations of vibrational bands intensities and depolarization ratios were recorded on changing the excitation wavelength. Three resonance levels were tentatively attributed to the presence of pure electronic transitions in band IV of the absorption spectra of these compounds. (author)

  18. 21 CFR 184.1443 - Magnesium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium sulfate. 184.1443 Section 184.1443 Food... Specific Substances Affirmed as GRAS § 184.1443 Magnesium sulfate. (a) Magnesium sulfate (MgSO4·7H2O, CAS... magnesium oxide, hydroxide, or carbonate with sulfuric acid and evaporating the solution to...

  19. Mineral resource of the month: magnesium

    Science.gov (United States)

    Kramer, Deborah A.

    2012-01-01

    Magnesium is the eighthmost abundant element in Earth’s crust, and the second-most abundant metal ion in seawater. Although magnesium is found in more than 60 minerals, only brucite, dolomite, magnesite and carnallite are commercially important for their magnesium content. Magnesium and its compounds also are recovered from seawater, brines found in lakes and wells, and bitterns (salts).

  20. 21 CFR 184.1431 - Magnesium oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium oxide. 184.1431 Section 184.1431 Food and... Substances Affirmed as GRAS § 184.1431 Magnesium oxide. (a) Magnesium oxide (MgO, CAS Reg. No. 1309-48-4... powder (light) or a relatively dense white powder (heavy) by heating magnesium hydroxide or...

  1. Magnesium Oxide Induced Metabolic Alkalosis in Cattle

    OpenAIRE

    Ogilvie, T. H.; Butler, D G; Gartley, C J; Dohoo, I R

    1983-01-01

    A study was designed to compare the metabolic alkalosis produced in cattle from the use of an antacid (magnesium oxide) and a saline cathartic (magnesium sulphate). Six, mature, normal cattle were treated orally with a magnesium oxide (MgO) product and one week later given a comparable cathartic dose of magnesium sulphate (MgSO4).

  2. Investigation of the Effects of COD/TP Ratio on the Performance of a Biological Nutrient Removal System

    OpenAIRE

    Punrattanasin, Warangkana

    1997-01-01

    The laboratory-scale University of Cape Town (UCT) process was designed to investigate the effects of changing COD/TP ratios on the performance of biological nutrient removal (BNR) processes. Specific objectives of the research were to investigate the effects of COD/TP ratio on the rates of phosphorus removal, COD removal, nitrogen removal, PHB utilization and oxygen uptake. The system was fed with municipal wastewater and operated at 20° C. The influent COD concentration was held approximat...

  3. On the capability of in-situ exposure in an environmental scanning electron microscope for investigating the atmospheric corrosion of magnesium

    International Nuclear Information System (INIS)

    The feasibility of environmental scanning electron microscope (ESEM) in studying the atmospheric corrosion behavior of 99.97% Mg was investigated. For reference, ex-situ exposure was performed. A model system was designed by spraying few salt particles on the metal surface and further promoting the corrosion process using platinum (Pt) deposition in the form of 1×1×1 µm3 dots around the salt particles to create strong artificial cathodic sites. The results showed that the electron beam play a significant role in the corrosion process of scanned regions. This was attributed to the irradiation damage occurring on the metal surface during the ESEM in-situ experiment. After achieving to a reliable process route, in a successful attempt, the morphology and composition of the corrosion products formed in-situ in the ESEM were in agreement with those of the sample exposed ex-situ. - Highlights: • The feasibility of in-situ microscopy and atmospheric corrosion exposures of pure Mg in an ESEM are examined. • A model system was designed using NaCl particles on parts of the metal surface and promoting the corrosion process by depositing 1×1×1 µm3 Pt dots to create strong artificial cathodic sites. • The electron beam used for ESEM imaging affects the in-situ corrosion process. • A proper cleaning procedure for the sample and microscope chamber reducing carbon contamination makes the results from the ESEM in-situ exposures comparable to ex-situ exposures

  4. Theoretical investigation of the mechanism for the cycloaddition of CO2 to epoxides catalyzed by a magnesium(II) porphyrin complex.

    Science.gov (United States)

    Wang, Qin; Guo, Cai-Hong; Jia, Jianfeng; Wu, Hai-Shun

    2015-07-01

    The cycloaddition of CO2 to epoxides, catalyzed by Mg(TPP)/TBAI (TPP = tetraphenylporphyrin; TBAI = tetrabutylammonium iodide), was investigated using DFT methods. Epoxides with various substituents were studied to explore steric and electronic effects on the reaction mechanism. Computational results show that the cycloaddition proceeds according to a much easier mechanism in the presence of Mg(TPP) and TBAI than the mechanism that takes place when Mg(TPP) is used as the catalyst. A preference for the epoxide ring-opening to occur at the methine (Cα) or methylene (Cβ) carbon was noted. The ring-closing step leading to the formation of a five-membered carbonate is predicted to determine the reaction rate. For alkyl-substituted epoxides, the β pathway is favorable since steric factors are dominant; for epoxides with a strongly electron-donating group and styrene oxide, the reaction is mainly controlled by electronic factors and proceeds along the α pathway. When the epoxide has a strongly electron-withdrawing group (CF3), both steric and electronic effects play important roles. The calculated reactivity of epoxides with CO2 catalyzed by Mg(TPP)/TBAI is in good agreement with that observed experimentally. PMID:26113116

  5. On the capability of in-situ exposure in an environmental scanning electron microscope for investigating the atmospheric corrosion of magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Esmaily, M., E-mail: mohsen.esmaily@chalmers.se [Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Mortazavi, N. [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Shahabi-Navid, M.; Svensson, J.E.; Johansson, L.G. [Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Halvarsson, M. [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden)

    2015-06-15

    The feasibility of environmental scanning electron microscope (ESEM) in studying the atmospheric corrosion behavior of 99.97% Mg was investigated. For reference, ex-situ exposure was performed. A model system was designed by spraying few salt particles on the metal surface and further promoting the corrosion process using platinum (Pt) deposition in the form of 1×1×1 µm{sup 3} dots around the salt particles to create strong artificial cathodic sites. The results showed that the electron beam play a significant role in the corrosion process of scanned regions. This was attributed to the irradiation damage occurring on the metal surface during the ESEM in-situ experiment. After achieving to a reliable process route, in a successful attempt, the morphology and composition of the corrosion products formed in-situ in the ESEM were in agreement with those of the sample exposed ex-situ. - Highlights: • The feasibility of in-situ microscopy and atmospheric corrosion exposures of pure Mg in an ESEM are examined. • A model system was designed using NaCl particles on parts of the metal surface and promoting the corrosion process by depositing 1×1×1 µm{sup 3} Pt dots to create strong artificial cathodic sites. • The electron beam used for ESEM imaging affects the in-situ corrosion process. • A proper cleaning procedure for the sample and microscope chamber reducing carbon contamination makes the results from the ESEM in-situ exposures comparable to ex-situ exposures.

  6. Optical storage by magnesium; Optisches Speichern von Magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Riedmann, Matthias

    2010-07-15

    Today, optical atomic frequency standards outperform those in the microwave range in terms of stability and accuracy. Relative uncertainties of 10{sup -18} are predicted for the near future. The spectroscopy of neutral atoms is carried out while they are stored in an optical lattice at the magic wavelength, where the transition frequency is not perturbed by the lattice. These systems have the potential to further increase the stability significantly due to the high number of atoms. Magnesium is one of the few elements that are suitable for a lattice-based optical frequency standard. In comparison to strontium, which is the mainly investigated element in such systems today, it has a much lower sensitivity to frequency shifts caused by blackbody radiation. This is one of the largest contributions to the uncertainty budget of state-of-the-art Sr lattice clocks. In this work, the trapping of magnesium in an optical dipole trap is investigated. This is a precursor for a future lattice-based frequency standard with magnesium. Magnesium is optically cooled in two magneto-optical traps (MOT). One of these traps (S-MOT) uses a transition in the singlet system, while the other (T-MOT) operates on a transition between two triplet levels. The T-MOT was constructed as part of the work presented here and is characterized for the first time. Atoms are loaded in the S-MOT and then transferred to the metastable (3s3p) {sup 3}P levels by optical excitation of the intercombination transition (3s{sup 2}) {sup 1}S{sub 0} {yields} (3s3p) {sup 3}P{sub 1}. This transfer takes only 10 ms. They are further cooled there in the T-MOT on transitions between the (3s3p) {sup 3}P and (3s3d) {sup 3}D triplets. More than 10{sup 8} atoms are stored in the T-MOT at a temperature of 1 mK. At these atom numbers, inelastic collisions between trapped atoms are observed and lead to fast atom loss. The loading of optical dipole traps at the wavelength 1064 nm and 532 nm is studied with the T-MOT as a

  7. The effect of magnesium on partial sulphate removal from mine water as gypsum.

    Science.gov (United States)

    Tolonen, Emma-Tuulia; Rämö, Jaakko; Lassi, Ulla

    2015-08-15

    The aim of this research was to investigate the effect of magnesium on the removal efficiency of sulphate as gypsum from mine water. The precipitation conditions were simulated with MINEQL + software and the simulation results were compared with the results from laboratory jar test experiments. Both the simulation and the laboratory results showed that magnesium in the mine water was maintaining sulphate in a soluble form as magnesium sulphate (MgSO4) at pH 9.6. Thus magnesium was preventing the removal of sulphate as gypsum (CaSO4·2H2O). However, change in the lime precipitation pH from 9.6 to 12.5 resulted in magnesium hydroxide (Mg(OH)2) precipitation and improved sulphate removal. Additionally, magnesium hydroxide could act as seed crystals for gypsum precipitation or co-precipitate sulphate further enhancing the removal of sulphate from mine water. PMID:26067895

  8. Bioactivity studies of calcium magnesium silicate prepared from eggshell waste by sol–gel combustion synthesis

    Directory of Open Access Journals (Sweden)

    Rajan Choudhary

    2015-06-01

    Full Text Available The present study focused on the synthesis of calcium magnesium silicate (akermanite, Ca2MgSi2O7 using eggshell biowaste (as calcium source, magnesium nitrate and tetraethyl orthosilicate (TEOS as starting materials. Sol–gel combustion method was adopted to obtain calcium magnesium silicate. Citric acid was used as a fuel (reducing agent and nitrate ions present in the metal nitrates acts as an oxidizing agent during combustion process. The characterization of synthesized calcium magnesium silicate was carried out by powder X-ray diffraction (XRD, Fourier transform infrared (FTIR and scanning electron microscopy (SEM techniques. Calcium magnesium silicate crystallite size was observed in nano regime which can effectively mimic natural bone apatite composition. In-vitro bioactivity was investigated by immersing calcium magnesium silicate pellet in simulated body fluid (SBF for three weeks. Results show effective deposition of crystallized hydroxyapatite (HAP layer on its surface and predicting its possibilities for applications in hard tissue regeneration.

  9. Corrosion of magnesium and aluminum in palm biodiesel: A comparative evaluation

    International Nuclear Information System (INIS)

    The present study aims to investigate the comparative corrosion of light-weight metals such as aluminum and magnesium in palm biodiesel. Immersion test at room temperature was carried out for each metal for 1440 h. Sample characterization techniques employed include weight loss measurement, SEM (scanning electron microscope), XRD (X-ray diffraction), TAN (total acid number) and FTIR (Fourier transform infrared spectroscopy). Results showed that the corrosion rate of magnesium was much higher compared to that of aluminum. The surface morphology revealed a significant difference between the biodiesel exposed aluminum and magnesium specimens. Upon exposure to biodiesel, the magnesium surface was found to be fully covered by gel-like sticky mass while the aluminum surface remained clean. - Highlights: • Biodiesel is highly corrosive for magnesium. • Biodiesel exposed magnesium surface showed yellowish gel-like sticky mass. • Biodiesel undergoes significant degradation upon exposure to metals

  10. Effect of Post Heat Treatment on Corrosion Resistance of Phytic Acid Conversion Coated Magnesium

    Institute of Scientific and Technical Information of China (English)

    R.K. Gupta; K. Mensah-Darkwa; D. Kumar

    2013-01-01

    An environment friendly chemical conversion coating for magnesium was obtained by using a phytic acid solution.The effect of post-coating 1heat treatment on the microstructures and corrosion properties of phytic acid conversion coated magnesium was investigated.It was observed that the microstructure and corrosion resistive properties were improved for the heat treated samples.The corrosion current density for bare magnesium,phytic acid conversion coated magnesium,and post-coating heat treated magnesium was calculated to be 2.48 × 10-5,1.18 × 10-6,and 9.27 × 10-7 A/cm2,respectively.The lowest corrosion current density for the heat treated sample indicated its highest corrosion resistive effect for the magnesium.The maximum corrosion protective nature of the heat treated sample was further confirmed by the largest value of impedance in electrochemical impedance spectroscopy studies.

  11. Susceptibility of metallic magnesium implants to bacterial biofilm infections.

    Science.gov (United States)

    Rahim, Muhammad Imran; Rohde, Manfred; Rais, Bushra; Seitz, Jan-Marten; Mueller, Peter P

    2016-06-01

    Magnesium alloys have promising mechanical and biological properties as biodegradable medical implant materials for temporary applications during bone healing or as vascular stents. Whereas conventional implants are prone to colonization by treatment resistant microbial biofilms in which bacteria are embedded in a protective matrix, magnesium alloys have been reported to act antibacterial in vitro. To permit a basic assessment of antibacterial properties of implant materials in vivo an economic but robust animal model was established. Subcutaneous magnesium implants were inoculated with bacteria in a mouse model. Contrary to the expectations, bacterial activity was enhanced and prolonged in the presence of magnesium implants. Systemic antibiotic treatments were remarkably ineffective, which is a typical property of bacterial biofilms. Biofilm formation was further supported by electron microscopic analyses that revealed highly dense bacterial populations and evidence for the presence of extracellular matrix material. Bacterial agglomerates could be detected not only on the implant surface but also at a limited distance in the peri-implant tissue. Therefore, precautions may be necessary to minimize risks of metallic magnesium-containing implants in prospective clinical applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1489-1499, 2016. PMID:26860452

  12. Investigations on the energy dependence of the biological action of fast neutrons

    International Nuclear Information System (INIS)

    A comparison was made between the action of 3.4-MeV and 14.7-MeV monoenergetic neutrons in four biological materials, namely: seeds of Hordeum vulgare and of Vicia faba, and spores of Aspergillus niger and Funaria hygrometrica. The neutrons were produced by the reactions 2H(d,n)3He and 3H(d,n)4He using a 600-keV cascade accelerator. Biological response was measured in terms of seedling growth, frequency of chromosome aberrations, or per cent survival. Dose response was compared for the two neutron energies and was found to differ significantly among the biological materials. The ratio of the radiation efficiency at the neutron energies did not agree with the value given by the conventional quality factors. (author). 4 refs, 2 tabs

  13. Lattice Dynamics of Magnesium

    International Nuclear Information System (INIS)

    A group theoretical analysis of modes of vibrations in hexagonal close-packed lattices has been made. The results have been used to classify the phonons at some special points in the Brillouin zone and factorized the secular determinant. Dispersion relations for phonons in magnesium along the two symmetry directions [0001] and [0110] have been measured (at room temperature) more accurately than reported earlier. The measurements have been made using a triple-axis spectrometer and a ''window filter'' spectrometer, both operated in the ''constant-Q'' mode. The results are compared with calculations based on three- and four-neighbour axially symmetric models. It is observed that the four-neighbour model gives a reasonably good description of the data. Even better agreement is obtained with a four-neighbour tensor force model. The force constants derived from the experiment have been used to compute the frequency distribution. (author)

  14. SERUM MAGNESIUM IN ACUTE MYOCARDIAL INFARCTION

    OpenAIRE

    Nambakam Tanuja; Girish P

    2015-01-01

    BACKGROUND: In myocardial infarction, there occurs functional deficit of available magnesium due to trapping of free magnesium in adipocytes. Magnesium has been implicated in the pathogenesis of acute myocardial infarction and its complications. Magnesium ions are considered essential for the maintenance of functional integrity of myocardium. The serum magnesium concentration was found to have g reat significance in acute myocardial infarction. The present study was un...

  15. Investigation of the effect of ionizing radiation on gene expression variation by the 'DNA chips': feasibility of a biological dosimeter

    International Nuclear Information System (INIS)

    After having described the different biological effects of ionizing radiation and the different approaches to biological dosimetry, and introduced 'DNA chips' or DNA micro-arrays, the author reports the characterization of gene expression variations in the response of cells to a gamma irradiation. Both main aspects of the use DNA chips are investigated: fundamental research and diagnosis. This research thesis thus proposes an analysis of the effect of ionizing radiation using DNA chips, notably by comparing gene expression modifications measured in mouse irradiated lung, heart and kidney. It reports a feasibility study of bio-dosimeter based on expression profiles

  16. Networks in biological systems: An investigation of the Gene Ontology as an evolving network

    International Nuclear Information System (INIS)

    Many biological systems can be described as networks where different elements interact, in order to perform biological processes. We introduce a network associated with the Gene Ontology. Specifically, we construct a correlation-based network where the vertices are the terms of the Gene Ontology and the link between each two terms is weighted on the basis of the number of genes that they have in common. We analyze a filtered network obtained from the correlation-based network and we characterize its evolution over different releases of the Gene Ontology.

  17. Electron spin interactions in chemistry and biology fundamentals, methods, reactions mechanisms, magnetic phenomena, structure investigation

    CERN Document Server

    Likhtenshtein, Gertz

    2016-01-01

    This book presents the versatile and pivotal role of electron spin interactions in nature. It provides the background, methodologies and tools for basic areas related to spin interactions, such as spin chemistry and biology, electron transfer, light energy conversion, photochemistry, radical reactions, magneto-chemistry and magneto-biology. The book also includes an overview of designing advanced magnetic materials, optical and spintronic devices and photo catalysts. This monograph appeals to scientists and graduate students working in the areas related to spin interactions physics, biophysics, chemistry and chemical engineering.

  18. Epigenetic Effects of Diet on Fruit Fly Lifespan: An Investigation to Teach Epigenetics to Biology Students

    Science.gov (United States)

    Billingsley, James; Carlson, Kimberly A.

    2010-01-01

    Do our genes exclusively control us, or are other factors at play? Epigenetics can provide a means for students to use inquiry-based methods to understand a complex biological concept. Students research and design an experiment testing whether dietary supplements affect the lifespan of Drosophila melanogaster over multiple generations.

  19. On-Demand Targeting: Investigating Biology with Proximity-Directed Chemistry

    Science.gov (United States)

    2016-01-01

    Proximity enhancement is a central chemical tenet underpinning an exciting suite of small-molecule toolsets that have allowed us to unravel many biological complexities. The leitmotif of this opus is “tethering”—a strategy in which a multifunctional small molecule serves as a template to bring proteins/biomolecules together. Scaffolding approaches have been powerfully applied to control diverse biological outcomes such as protein–protein association, protein stability, activity, and improve imaging capabilities. A new twist on this strategy has recently appeared, in which the small-molecule probe is engineered to unleash controlled amounts of reactive chemical signals within the microenvironment of a target protein. Modification of a specific target elicits a precisely timed and spatially controlled gain-of-function (or dominant loss-of-function) signaling response. Presented herein is a unique personal outlook conceptualizing the powerful proximity-enhanced chemical biology toolsets into two paradigms: “multifunctional scaffolding” versus “on-demand targeting”. By addressing the latest advances and challenges in the established yet constantly evolving multifunctional scaffolding strategies as well as in the emerging on-demand precision targeting (and related) systems, this Perspective is aimed at choosing when it is best to employ each of the two strategies, with an emphasis toward further promoting novel applications and discoveries stemming from these innovative chemical biology platforms. PMID:26907082

  20. Investigation of Pre-Service Science Teachers' Academic Self-Efficacy and Academic Motivation toward Biology

    Science.gov (United States)

    Ates, Hüseyin; Saylan, Asli

    2015-01-01

    The purpose of this research was to examine pre-service science teachers' academic motivation and academic self-efficacy toward biology. The sample consisted of 369 pre-service science teachers who enrolled in the faculty of education of two universities in Turkey. Data were collected through Academic Motivation Scale (AMS) (Glynn & Koballa,…

  1. An investigation on impacts of scheduling configurations on Mississippi biology subject area testing

    Science.gov (United States)

    Marchette, Frances Lenora

    The purpose of this mixed modal study was to compare the results of Biology Subject Area mean scores of students on a 4 x 4 block schedule, A/B block schedule, and traditional year-long schedule for 1A to 5A size schools. This study also reviewed the data to determine if minority or gender issues might influence the test results. Interviews with administrators and teachers were conducted about the type of schedule configuration they use and the influence that the schedule has on student academic performance on the Biology Subject Area Test. Additionally, this research further explored whether schedule configurations allow sufficient time for students to construct knowledge. This study is important to schools, teachers, and administrators because it can assist them in considering the impacts that different types of class schedules have on student performance and if ethnic or gender issues are influencing testing results. This study used the causal-comparative method for the quantitative portion of the study and constant comparative method for the qualitative portion to explore the relationship of school schedules on student academic achievement on the Mississippi Biology Subject Area Test. The aggregate means of selected student scores indicate that the Mississippi Biology Subject Area Test as a measure of student performance reveals no significant difference on student achievement for the three school schedule configurations. The data were adjusted for initial differences of gender, minority, and school size on the three schedule configurations. The results suggest that schools may employ various schedule configurations and expect student performance on the Mississippi Biology Subject Area Test to be unaffected. However, many areas of concern were identified in the interviews that might impact on school learning environments. These concerns relate to effective classroom management, the active involvement of students in learning, the adequacy of teacher education

  2. Effect of magnesium deficiency on renal magnesium and calcium transport in the rat.

    OpenAIRE

    Carney, S L; Wong, N L; Quamme, G A; Dirks, J.H.

    1980-01-01

    Recollection of micropuncture experiments were performed on acutely thyroparathyroidectomized rats rendered magnesium deficient by dietary deprivation. Urinary magnesium excretion fell from a control of 15 to 3% of the filtered load after magnesium restriction. The loop of Henle, presumably the thick ascending limb, was the major modulator for renal magnesium homeostasis. The transport capacity for magnesium, however, was less in deficient rats than control animals. Absolute magnesium reabsor...

  3. Synthesis, biological investigation, calf thymus DNA binding and docking studies of the sulfonyl hydrazides and their derivatives

    Science.gov (United States)

    Murtaza, Shahzad; Shamim, Saima; Kousar, Naghmana; Tahir, Muhammad Nawaz; Sirajuddin, Muhammad; Rana, Usman Ali

    2016-03-01

    The present study describes the syntheses and biological investigations of sulfonyl hydrazides and their novel derivatives. The detailed investigations involved the characterization of the newly synthesized compounds using FTIR, NMR, mass spectrometry and by single crystal X-Ray diffraction (XRD) analysis techniques. The binding tendencies of these compounds with CT-DNA (calf thymus DNA) have been explored by electronic absorption (UV) spectroscopy and viscosity measurement. The binding constant (K) and Gibb's free energy (ΔG) values were also calculated accordingly. In addition, we also investigated the biological activities such as antioxidant, antibacterial, enzyme inhibition and DNA interactions. The antioxidant activity was assayed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, while antibacterial activity was investigated against four bacterial strains (viz. Escherichia coli, Crynibacteria bovius, Staphylococcus auras and Bacillus antherasis) by employing the common disc diffusion method. Enzyme inhibition activity of the synthesized compounds was examined against butyrylcholinestrase. The results of enzyme inhibition activity and the DNA binding interaction studies were also collected through molecular docking program using computational analysis. Our study reveals that the newly synthesized compounds possess moderate to good biological activities.

  4. Investigation of sintering kinetics of magnesium titanate

    Directory of Open Access Journals (Sweden)

    Petrović V.V.

    2013-01-01

    Full Text Available Obtaining new materials including sintered electronic materials using different procedures is the consequence of long complex and expensive experimental work. However, the dynamics of expansive development of electronic devices requires fast development of new materials, especially sintered oxide materials. The recent rapid development of electronics is among other things due to development and improvement of new components based on titanate ceramics. Research in this work has included an experimental study of the synthesis of dielectric ceramics in the system MgCO3 - TiO2. Starting powders were mechanically activated by milling in a high energy planetary mill for different times. Samples were prepared for isothermal sintering at 1100ºC by dual pressing of powders into cylindrical samples in a hydraulic press.

  5. Enhancements in Magnesium Die Casting Impact Properties

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Yulong Zhu; Srinath Viswanathan; Shafik Iskander

    2000-06-30

    The need to produce lighter components in transportation equipment is the main driver in the increasing demand for magnesium castings. In many automotive applications, components can be made of magnesium or aluminum. While being lighter, often times the magnesium parts have lower impact and fatigue properties than the aluminum. The main objective of this study was to identify potential improvements in the impact resistance of magnesium alloys. The most common magnesium alloys in automotive applications are AZ91D, AM50 and AM60. Accordingly, these alloys were selected as the main candidates for the study. Experimental quantities of these alloys were melted in an electrical furnace under a protective atmosphere comprising sulfur hexafluoride, carbon dioxide and dry air. The alloys were cast both in a permanent mold and in a UBE 315 Ton squeeze caster. Extensive evaluation of tensile, impact and fatigue properties was conducted at CWRU on permanent mold and squeeze cast test bars of AZ91, AM60 and AM50. Ultimate tensile strength values between 20ksi and 30ksi were obtained. The respective elongations varied between 25 and 115. the Charpy V-notch impact strength varied between 1.6 ft-lb and 5 ft-lb depending on the alloy and processing conditions. Preliminary bending fatigue evaluation indicates a fatigue limit of 11-12 ksi for AM50 and AM60. This is about 0.4 of the UTS, typical for these alloys. The microstructures of the cast specimens were investigated with optical and scanning electron microscopy. Concomitantly, a study of the fracture toughness in AM60 was conducted at ORNL as part of the study. The results are in line with values published in the literature and are representative of current state of the art in casting magnesium alloys. The experimental results confirm the strong relationship between aluminum content of the alloys and the mechanical properties, in particular the impact strength and the elongation. As the aluminum content increases from about 5

  6. Nanocrystalline magnesium and its properties of hydrogen sorption

    Directory of Open Access Journals (Sweden)

    E. David

    2007-01-01

    Full Text Available Purpose: The goal of this paper is to study the possibility of obtaining of magnesium and magnesium hydride innanocrystallyne form and then to activate these materials for to be used in efficient systems of hydrogen storage.Design/methodology/approach: The magnesium hydride (MgH2 was directly synthesised from mechanicallygrinded magnesium powder obtained through ball milling of Mg (BM, and hydrogen of high purity. The MgH2was then chemical activation by surface modification of nanocrystalline Mg with nichel ultafine particlesaddition.The hydrogen sorption properties of the nanocrystalline Mg were investigated by a conventionalpressure-volume-temperature technique, X-ray diffraction , and scanning electron microscopy (SEM.Findings: We found that the mechanical activation improved significantly the kinetics of hydrogen absorptionin nanocrystalline magnesium, increasing sorption rates by up to 2 orders of magnitude. A profound effect of thepowder particle size on the hydrogen desorption characteristics has been also observed. It was also determined thatthe Mg2Ni compound absorbed hydrogen quickly and showed excellent hydrogen sortption properties at 300oC.Research limitations/implications: The reduction of the particle size of magnesium and the creation of freshsurfaces by mechanical ball milling help the kinetics but does not affect the thermodynamics.Practical implications: Further examination to obtain improved properties of hydrogen sorption process ofmagnesium based materials and investigations of achievement of new systems for hydrogen solid storage.Originality/value: This work contains new aspects, which show the conditions of obtaining of nanocrystallinemetal clusters with size under 30nm and represents new approach of improvement of hydrogen sorption processin light metals, such as magnesium, that can provide promising results for the hydrogen storage applications.

  7. INVESTIGATION OF INTERMITTENT CHLORINATION SYSTEM IN BIOLOGICAL EXCESS SLUDGE REDUCTION BY SEQUENCING BATCH REACTORS

    OpenAIRE

    A. Takdastan ، N. Mehrdadi ، A. A. Azimi ، A. Torabian ، G. Nabi Bidhendi

    2009-01-01

    The excessive biological sludge production is one of the disadvantages of aerobic wastewater treatment processes such as sequencing batch reactors. To solve the problem of excess sludge production, oxidizing some of the sludge by chlorine, thus reducing the biomass coefficient as well as the sewage sludge disposal may be a suitable idea. In this study, two sequencing batch reactors, each with 20 L volume and controlled by on-line system were used. After providing the steady state conditions i...

  8. Investigation of human exposure to triclocarban after showering, and preliminary evaluation of its biological effects

    OpenAIRE

    Schebb, Nils Helge; Inceoglu, Bora; Ahn, Ki Chang; Morisseau, Christophe; Gee, Shirley; Hammock, Bruce D.

    2011-01-01

    The antibacterial soap additive triclocarban (TCC) is widely used in personal care products. TCC has a high environmental persistence. We developed and validated a sensitive online solid phase extraction-LC-MS/MS method to rapidly analyze TCC and its major metabolites in urine and other biological samples to assess human exposure. We measured human urine concentrations 0–72 h after showering with a commercial bar soap containing 0.6% TCC. The major route of renal elimination was excretion as ...

  9. Chemical kinetic mechanistic models to investigate cancer biology and impact cancer medicine

    Science.gov (United States)

    Stites, Edward C.

    2013-04-01

    Traditional experimental biology has provided a mechanistic understanding of cancer in which the malignancy develops through the acquisition of mutations that disrupt cellular processes. Several drugs developed to target such mutations have now demonstrated clinical value. These advances are unequivocal testaments to the value of traditional cellular and molecular biology. However, several features of cancer may limit the pace of progress that can be made with established experimental approaches alone. The mutated genes (and resultant mutant proteins) function within large biochemical networks. Biochemical networks typically have a large number of component molecules and are characterized by a large number of quantitative properties. Responses to a stimulus or perturbation are typically nonlinear and can display qualitative changes that depend upon the specific values of variable system properties. Features such as these can complicate the interpretation of experimental data and the formulation of logical hypotheses that drive further research. Mathematical models based upon the molecular reactions that define these networks combined with computational studies have the potential to deal with these obstacles and to enable currently available information to be more completely utilized. Many of the pressing problems in cancer biology and cancer medicine may benefit from a mathematical treatment. As work in this area advances, one can envision a future where such models may meaningfully contribute to the clinical management of cancer patients.

  10. 78 FR 1834 - Magnesium Metal From the People's Republic of China: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2013-01-09

    ... Notice of Antidumping Duty Order: Magnesium Metal From the People's Republic of China, 70 FR 19928 (April... Countervailing Duty Administrative Review, 77 FR 31568 (May 29, 2012). \\4\\ See letter from TMI, ``Magnesium Metal... Order, Finding, or Suspended Investigation; Opportunity To Request Administrative Review, 77 FR...

  11. Microstructure of AM50 die casting magnesium alloy

    Directory of Open Access Journals (Sweden)

    A. Kiełbus

    2006-08-01

    Full Text Available Purpose: AM50 magnesium alloy allows high-energy absorption and elongation at high strength and has goodcastability. It contains aluminum and manganese. Typically, it is used in automotive industry for steering wheels,dashboards and seat frames. The aim of this paper is to present the results of investigations on the microstructureof the AM50 magnesium alloy in an ingot condition and after hot chamber die casting.Design/methodology/approach: Die casting was carried out on 280 tone locking force hot-chamber die castingmachine. For the microstructure observation, a Olympus GX+70 metallographic microscope and a HITACHIS-3400N scanning electron microscope with a Thermo Noran EDS spectrometer equipped with SYSTEM SIXwere used.Findings: Based on the investigation carried out it was found that the AM50 magnesium alloy in as ingotcondition is characterized by a solid solution structure a with partially divorced eutectic (a + Mg17Al12 andprecipitates of Mn5Al8 phase. After hot chamber die casting is characterized by a solid solution structure awith fully divorced eutectic a + Mg17Al12. Moreover, the occurrence of Mn5Al8 phase and some shrinkageporosity has been proved.Research limitations/implications: Future researches should contain investigations of the influence of the diecasting process parameters on the microstructure and mechanical properties of AM50 magnesium.Practical implications: AM50 magnesium alloy can be cast with cold- and hot-chamber die casting machine.Results of investigation may be useful for preparing die casting technology of this alloy.Originality/value: The results of the researches make up a basis for the investigations of new magnesium alloysfor hot chamber die casting with addition of RE elements designed to exploitation in temperature to 175°C.

  12. Treatment with magnesium sulphate in pre-term birth

    DEFF Research Database (Denmark)

    Wolf, Hans; Hegaard, H K; Greisen, G;

    2012-01-01

    Premature birth increases a child's risk of cerebral palsy and death. The aim of this work is to investigate the association between treatment with magnesium sulphate during premature deliveries and infants' cerebral palsy and mortality through a meta-analysis of observational studies. A comprehe......Premature birth increases a child's risk of cerebral palsy and death. The aim of this work is to investigate the association between treatment with magnesium sulphate during premature deliveries and infants' cerebral palsy and mortality through a meta-analysis of observational studies....... A comprehensive search of the Cochrane Library, EMBASE and the PubMed database from their inceptions to 1 October, 2010 using the keywords 'magnesium sulphate, children/infant/pre-term/premature and cerebral palsy/mortality/morbidity/adverse effects/outcome' identified 11 reports of observational studies. Two...... authors working independently extracted the data. A meta-analysis of the data found an association between magnesium sulphate treatment and a significantly reduced risk of mortality (RR 0.73; 95% CI 0.61-0.89) and cerebral palsy (OR 0.64; 95% CI 0.47-0.89). Antenatal treatment with magnesium sulphate...

  13. Facile and fast fabrication of superhydrophobic surface on magnesium alloy

    Science.gov (United States)

    Wang, Zhongwei; Li, Qing; She, Zuxin; Chen, Funan; Li, Longqin; Zhang, Xiaoxu; Zhang, Peng

    2013-04-01

    Superhydrophobic surface has many special functions and is widely investigated by researchers. Magnesium alloy is one of the lightest metal materials among the practice metals. It plays an important role in automobile, airplane and digital product for reducing devices weight. But due to the low standard potential, magnesium alloy has a high chemical activity and easily be corroded. That seriously impedes the application of magnesium alloy. In the process of fabrication a superhydrophobic surface on magnesium alloy, there are two ineluctable problems that must be solved: (1) high chemical activity and (2) the chemical activity is inhomogeneous on surface. In this study, we solved those problems by using the two characters to gain a rough surface on magnesium alloy and obtained a superhydrophobic surface after following modification process. The results show that the as-prepared superhydrophobic surface has obvious anti-corrosion effect in typically corrosive solution and naturally humid air. The delay-icing and self-cleaning effects are also investigated. The presented method is low-cost, fast and has great potential value in large-scale industry production.

  14. Biological investigations of the Sandia National Laboratories Sol se Mete Aerial Cable Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, R.M.

    1994-10-01

    This report provides results of a comprehensive biological field survey performed on the Sandia National Laboratories Aerial Cable Facility, at the east end of Kirtland Air Force Base (KAFB), Bernalillo County, New Mexico. This survey was conducted late September through October, 1991. ACF occupies a 440-acre tract of land withdrawn by the US Forest Service (USFS) for use by KAFB, and in turn placed under operational control of SNL by the Department of Energy (DOE). All land used by SNL for ACF is part of a 15,851-acre tract of land withdrawn by the US Forest Service. In addition, a number of different organizations use the 15,851-acre area. The project area used by SNL encompasses portions of approximately six sections (3,840 acres) of US Forest Service land located within the foothills of the west side of the Manzano Mountains (East Mesa). The biological study area is used by the KAFB, the US Department of Interior, and SNL. This area includes: (1) Sol se Mete Springs and Canyon, (2) East Anchor Access Road, (3) East Anchor Site, (4) Rocket Sled Track, (5) North Arena, (6) East Instrumentation Site and Access Road, (7) West Anchor Access Road, (8) West Anchor Site, (9) South Arena, (10) Winch Sites, (11) West Instrumentation Sites, (12) Explosive Assembly Building, (13) Control Building, (14) Lurance Canyon Road and vicinity. Although portions of approximately 960 acres of withdrawn US Forest Service land have been altered, only 700 acres have been disturbed by activities associated with ACF; approximately 2,880 acres consist of natural habitat. Absence of grazing by livestock and possibly native ungulates, and relative lack of human disturbance have allowed this area to remain in a more natural vegetative state relative to the condition of private range lands throughout New Mexico. This report evaluates threatened and endangered species found on ACF, as well as a comprehensive assessment of biological habitats.

  15. Investigations in the degradation of polar and non-polar exit air constituents in biological scrubbers

    International Nuclear Information System (INIS)

    On a semi-technical scale (exit air volume flows between 1000 m3.h-1 and 3600 m3.h-1), experiments in the treatment of exit air from a mixed production plant of the chemical industry by biological absorption process were carried through. During testing, the configuration of the pilot plant was changed. Thus, both a multiple-zone nozzle scrubber and a packed column were used as an absorber, and as a scrubbing liquid both aerated sludge and a dispersion of aerated sludge and silicon oil with silicon oil contents of up to 5% wer used. (orig.)

  16. Trienamine catalyzed asymmetric synthesis and biological investigation of a cytochalasin B-inspired compound collection.

    Science.gov (United States)

    Sellstedt, Magnus; Schwalfenberg, Melanie; Ziegler, Slava; Antonchick, Andrey P; Waldmann, Herbert

    2016-01-01

    Due to their enhanced metabolic needs many cancers need a sufficient supply of glucose, and novel inhibitors of glucose import are in high demand. Cytochalasin B (CB) is a potent natural glucose import inhibitor which also impairs the actin cytoskeleton leading to undesired toxicity. With a view to identifying selective glucose import inhibitors we have developed an enantioselective trienamine catalyzed synthesis of a CB-inspired compound collection. Biological analysis revealed that indeed actin impairment can be distinguished from glucose import inhibition and led to the identification of the first selective glucose import inhibitor based on the basic structural architecture of cytochalasin B. PMID:26606903

  17. Investigations involving oxidation-reduction (REDOX) pretreatment in conjunction with biological remediation of contaminated soils

    International Nuclear Information System (INIS)

    Oxidation-reduction (REDOX) reactions are among the most important reactions involved in the environmental engineering field. Oxidation is a reaction in which the oxidation state of the treated compound is increased, i.e., the material loses electrons. Reduction involves the addition of a chemical (reducing) agent which lowers the oxidation state of a substance, i.e., the material gains electrons. Both processes of oxidation and reduction occur together. All REDOX reactions are thermodynamically based. There are a number of oxidizing agents which have been reported in the technical literature for treatment of refractory organic compounds. Common oxidizing agents include: hydrogen peroxide, ozone, ultraviolet (UV) irradiation, and combinations thereof, such as UV/ozone and UV/peroxide. A gradient of REDOX reactions is possible, depending on such factors as the oxidation-reduction reaction conditions, the availability of electron donors and acceptors, and the nature of the organic compounds involved. A review of the technical literature revealed that the majority of the oxidation-reduction applications have been in the areas of wastewater treatment and groundwater remediation, with very little attention devoted to the potential of using REDOX technologies for remediation of hydrocarbon contaminated soils. In this particular study, feasibility studies were performed on gasoline- contaminated soil. These studies focused on three major phases: 1) containment of the contamination by addition of tailoring agents to the soil, 2) biological remediation either performed in situ or on-site (using a slurry reactor system), and 3) pretreatment of the contaminated soils using REDOX systems, prior to biological remediation. This particular paper focuses on the third phase of the project, aimed at ''softening'' the refractory organics resulting in the formation of organic compounds which are more amenable to biological degradation. This paper focuses its attention on the use of

  18. FORMATION OF HA-CONTAINING COATING ON AZ31 MAGNESIUM ALLOY BY MICRO-ARC OXIDATION

    OpenAIRE

    HUI TANG; DEYU LI; XIUPING CHEN; CHAO WU; FUPING WANG

    2013-01-01

    Magnesium and its alloys are potential biodegradable implant materials due to their attractive biological properties. But the use of magnesium is still hampered by its poor corrosion resistance in physiological fluids. In this study, a HA-containing coating was fabricated by micro-arc oxidation (MAO). The active plasma species of micro-discharge was studied by optical emission spectroscopy (OES). The microstructure and composition were analyzed by scanning electron microscopy (SEM) and X-ray ...

  19. INVESTIGATION OF INTERMITTENT CHLORINATION SYSTEM IN BIOLOGICAL EXCESS SLUDGE REDUCTION BY SEQUENCING BATCH REACTORS

    Directory of Open Access Journals (Sweden)

    A. Takdastan ، N. Mehrdadi ، A. A. Azimi ، A. Torabian ، G. Nabi Bidhendi

    2009-01-01

    Full Text Available The excessive biological sludge production is one of the disadvantages of aerobic wastewater treatment processes such as sequencing batch reactors. To solve the problem of excess sludge production, oxidizing some of the sludge by chlorine, thus reducing the biomass coefficient as well as the sewage sludge disposal may be a suitable idea. In this study, two sequencing batch reactors, each with 20 L volume and controlled by on-line system were used. After providing the steady state conditions in the reactors, sampling and testing of parameters were done during 8 months. The results showed that during the solid retention time of 10 days the kinetic coefficient of Y and Kd were 0.58 mg biomass/mg COD and 0.058/day, respectively. At the next stage, different concentrations of chlorine were used in the reactors intermittently. Results showed that 15 mg chlorine/gMLSS in the reactor was able to reduce the yield coefficient from 0.58 to 0.3 mg biomass/mg COD. In other words, the biological excess sludge was reduced about 48%. But the soluble chemical oxygen demand increased slightly in the effluent and the removal percentage decreased from 95% in the blank reactor to 55% in the test reactor.

  20. Investigation of human exposure to triclocarban after showering and preliminary evaluation of its biological effects.

    Science.gov (United States)

    Schebb, Nils Helge; Inceoglu, Bora; Ahn, Ki Chang; Morisseau, Christophe; Gee, Shirley J; Hammock, Bruce D

    2011-04-01

    The antibacterial soap additive triclocarban (TCC) is widely used in personal care products. TCC has a high environmental persistence. We developed and validated a sensitive online solid-phase extraction-LC-MS/MS method to rapidly analyze TCC and its major metabolites in urine and other biological samples to assess human exposure. We measured human urine concentrations 0-72 h after showering with a commercial bar soap containing 0.6% TCC. The major route of renal elimination was excretion as N-glucuronides. The absorption was estimated at 0.6% of the 70±15 mg of TCC in the soap used. The TCC-N-glucuronide urine concentration varied widely among the subjects, and continuous daily use of the soap led to steady state levels of excretion. In order to assess potential biological effects arising from this exposure, we screened TCC for the inhibition of human enzymes in vitro. We demonstrate that TCC is a potent inhibitor of the enzyme soluble epoxide hydrolase (sEH), whereas TCC's major metabolites lack strong inhibitory activity. Topical administration of TCC at similar levels to rats in a preliminary in vivo study, however, failed to alter plasma biomarkers of sEH activity. Overall the analytical strategy described here revealed that use of TCC soap causes exposure levels that warrant further evaluation. PMID:21381656

  1. Investigation of activated biological sludge particles sedimentation in rectangular settling basin

    International Nuclear Information System (INIS)

    Clarifying is the final step of biological sewage treatment plant. Usually this step is realized in big rectangular basins. The efficiency of sediment removal decreases during process run parallely to quantity of deposited sludge in the basin volume. Extension of basin exploitation time needs removal of deposited sediment during the technological campaign. But proper localization of any removing device in basin cross-section should be preceded by the measurement of mean sedimentation range. For that purpose the radiotracer (La-140) experiment has been carried out at the big (340 x 55 x 3 m) clarifier working in the petrochemical industry. The experiments have been conducted in two steps of basin filling with biological sludge, 15 and 50%. The distributions of labelled sediments on the basin bottom have been measured as well as RTD for sewage labelled with rhodamine B and also RTD for residual suspended sediment grains at basin outlet. Sedimentation mechanism has been discussed and 'favourable' sedimentation range has been determined. (author)

  2. Summary of biological investigations relating to surface-water quality in the Kentucky River basin, Kentucky

    Science.gov (United States)

    Bradfield, A.D.; Porter, S.D.

    1990-01-01

    The Kentucky River basin, an area of approximately 7,000 sq mi, is divided into five hydrologic units that drain parts of three physiographic regions. Data on aquatic biological resources were collected and reviewed to assess conditions in the major streams for which data were available. The North, Middle, and South Forks of the Kentucky River are in the Eastern Coal Field physiographic region. Streams in this region are affected by drainage from coal mines and oil and gas operations, and many support only tolerant biotic stream forms. The Kentucky River from the confluence of the three forks to the Red River, is in the Knobs physiographic region. Oil and gas production operations and point discharges from municipalities have affected many streams in this region. The Red River, a Kentucky Wild River, supported a unique flora and fauna but accelerated sedimentation has eliminated many species of mussels. The Millers Creek drainage is affected by brines discharged from oil and gas operations, and some reaches support only halophilic algae and a few fish. The Kentucky River from the Red River to the Ohio River is in the Bluegrass physiographic region. Heavy sediment loads and sewage effluent from urban centers have limited the aquatic biota in this region. Silver Creek and South Elkhorn Creek have been particularly affected and aquatic communities in these streams are dominated by organisms tolerant of low dissolved oxygen concentrations. Biological data for other streams indicate that habitat and water quality conditions are favorable for most commonly occurring aquatic organisms. (USGS)

  3. "Rinse and trickle": a protocol for TEM preparation and investigation of inorganic fibers from biological material.

    Science.gov (United States)

    Vigliaturo, Ruggero; Capella, Silvana; Rinaudo, Caterina; Belluso, Elena

    2016-07-01

    The purpose of this work is to define a sample preparation protocol that allows inorganic fibers and particulate matter extracted from different biological samples to be characterized morphologically, crystallographically and chemically by transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS). The method does not damage or create artifacts through chemical attacks of the target material. A fairly rapid specimen preparation is applied with the aim of performing as few steps as possible to transfer the withdrawn inorganic matter onto the TEM grid. The biological sample is previously digested chemically by NaClO. The salt is then removed through a series of centrifugation and rinse cycles in deionized water, thus drastically reducing the digestive power of the NaClO and concentrating the fibers for TEM analysis. The concept of equivalent hydrodynamic diameter is introduced to calculate the settling velocity during the centrifugation cycles. This technique is applicable to lung tissues and can be extended to a wide range of organic materials. The procedure does not appear to cause morphological damage to the fibers or modify their chemistry or degree of crystallinity. The extrapolated data can be used in interdisciplinary studies to understand the pathological effects caused by inorganic materials. PMID:27151190

  4. Investigating the robustness of ion beam therapy treatment plans to uncertainties in biological treatment parameters

    CERN Document Server

    Boehlen, T T; Dosanjh, M; Ferrari, A; Fossati, P; Haberer, T; Mairani, A; Patera, V

    2012-01-01

    Uncertainties in determining clinically used relative biological effectiveness (RBE) values for ion beam therapy carry the risk of absolute and relative misestimations of RBE-weighted doses for clinical scenarios. This study assesses the consequences of hypothetical misestimations of input parameters to the RBE modelling for carbon ion treatment plans by a variational approach. The impact of the variations on resulting cell survival and RBE values is evaluated as a function of the remaining ion range. In addition, the sensitivity to misestimations in RBE modelling is compared for single fields and two opposed fields using differing optimization criteria. It is demonstrated for single treatment fields that moderate variations (up to +/-50\\%) of representative nominal input parameters for four tumours result mainly in a misestimation of the RBE-weighted dose in the planning target volume (PTV) by a constant factor and only smaller RBE-weighted dose gradients. Ensuring a more uniform radiation quality in the PTV...

  5. First synthesis of racemic saphenamycin and its enantiomers. Investigation of biological activity

    DEFF Research Database (Denmark)

    Laursen, Jane B.; Jorgensen, C.G.; Nielsen, John

    2003-01-01

    The natural antibiotic saphenamycin, 6-[1-(2-hydroxy-6-methyl-benzoyloxy)-ethyl]-phenazine-1-carboxylic acid, was synthesized from saphenic acid using temporary ally] protection of carboxy and phenoxy functionalities. Resolution of racemic saphenic acid was performed by crystallization of the...... and screened against a range of skin flora and resistant Staphylococcus aureus strains. Biological activities of saphenamycin enantiomers were compared with that of the synthetic racemate as well as earlier reported activities of saphenamycin isolated from natural sources. No significant difference...... was observed in activity of the enantiomers of saphenamycin, which revealed that the chirality of saphenamycin has no consequences for the antibiotic activity. Saphenamycin proved to be a potent antibiotic against fusidic acid and rifampicin resistant S. aureus strains showing MIC of 0.1-0.2 mug/mL....

  6. Investigation on biological properties of tacrolimus-loaded poly(1,3-trimethylene carbonate) in vitro

    Science.gov (United States)

    Hou, Ruixia; Wu, Leigang; Wang, Jin; Huang, Nan

    2010-06-01

    The drug-eluting stents have been regarded as a milestone in inhibiting the restenosis of coronary arteries. However, adverse reactions caused by bare-metal stents and non-biodegradable polymer coatings may result in some clinical problems. In this study, a new tacrolimus-eluting stent coated with biodegradable poly(1,3-trimethylene carbonate) (PTMC) is developed. The structures are characterized by Fourier transform infrared (FTIR) analysis, and the wettability is measured by contact angle assay. The biological behaviors are evaluated by the in vitro platelets adhesion test, APTT test, the human umbilical cord artery smooth muscle cells (HUCASMCs), 4',6-diamidine-2-phenylindole (DAPI) and actin immunofluorescence staining, MTT colorimetric assay. These results show that after blending tacrolimus into PTMC, the anticoagulant behavior is improved, and the adhesion and proliferation of HUCASMCs on samples are inhibited. This work aims to find one kind of surface erosion biodegradable polymers that can be applied as drug-eluting stent coatings.

  7. Investigation on biological properties of tacrolimus-loaded poly(1,3-trimethylene carbonate) in vitro

    International Nuclear Information System (INIS)

    The drug-eluting stents have been regarded as a milestone in inhibiting the restenosis of coronary arteries. However, adverse reactions caused by bare-metal stents and non-biodegradable polymer coatings may result in some clinical problems. In this study, a new tacrolimus-eluting stent coated with biodegradable poly(1,3-trimethylene carbonate) (PTMC) is developed. The structures are characterized by Fourier transform infrared (FTIR) analysis, and the wettability is measured by contact angle assay. The biological behaviors are evaluated by the in vitro platelets adhesion test, APTT test, the human umbilical cord artery smooth muscle cells (HUCASMCs), 4',6-diamidine-2-phenylindole (DAPI) and actin immunofluorescence staining, MTT colorimetric assay. These results show that after blending tacrolimus into PTMC, the anticoagulant behavior is improved, and the adhesion and proliferation of HUCASMCs on samples are inhibited. This work aims to find one kind of surface erosion biodegradable polymers that can be applied as drug-eluting stent coatings.

  8. Investigating the biology of plant infection by the rice blast fungus Magnaporthe oryzae.

    Science.gov (United States)

    Martin-Urdiroz, Magdalena; Oses-Ruiz, Miriam; Ryder, Lauren S; Talbot, Nicholas J

    2016-05-01

    The rice blast fungus, Magnaporthe oryzae, is responsible for the most serious disease of rice and is a continuing threat to ensuring global food security. The fungus has also, however, emerged as a model experimental organism for understanding plant infection processes by pathogenic fungi. This is largely due to its amenability to both classical and molecular genetics, coupled with the efforts of a very large international research community. This review, which is based on a plenary presentation at the 28th Fungal Genetics Conference in Asilomar, California in March 2015, describes recent progress in understanding how M. oryzae uses specialised cell called appressoria to bring about plant infection and the underlying biology of this developmental process. We also review how the fungus is then able to proliferate within rice tissue, deploying effector proteins to facilitate its spread by suppressing plant immunity and promoting growth and development of the fungus. PMID:26703899

  9. Nanostructured Magnesium Hydride for Reversible Hydrogen Storage

    Science.gov (United States)

    de Rango, P.; Chaise, A.; Fruchart, D.; Miraglia, S.; Marty, Ph.

    2013-05-01

    The aim of this work was to develop suitable materials to store hydrogen in a solid state. A systematic investigation of the co-milling process of magnesium hydride with a transition metal was undertaken in order to produce nanostructured and highly reactive powders. The initiating role of the transition metal was evidenced by in situ neutron diffraction experiments. High performances in terms of thermal and mechanical behavior were achieved introducing expanded graphite and compacting the mixture to form composite materials. Absorption and desorption kinetics have been measured versus temperature and H2 pressure.

  10. Summary of biological investigations relating to surface-water quality in the Kentucky River Basin, Kentucky

    International Nuclear Information System (INIS)

    The Kentucky River basin, an area of approximately 7,000 sq mi, is divided into five hydrologic units that drain parts of three physiographic regions. Data on aquatic biological resources were collected and reviewed to assess conditions in the major streams for which data were available. The North, Middle, and south Forks of the Kentucky River are in the Eastern Coal Field physiographic region. Streams in this region are affected by drainage from coal mines and oil and gas operations, and many support only tolerant biotic stream forms. The Kentucky River from the confluence of the three forks to the Red River, is in the Knobs physiographic region. Oil and gas production operations and point discharges from municipalities have affected many streams in this region. The Red River, a Kentucky Wild River, supported a unique flora and fauna but accelerated sedimentation has eliminated many species of mussels. The Millers Creek drainage is affected by brines discharged from oil and gas operations, and some reaches support only halophilic algae and a few fish. The Kentucky River from the Red River to the Ohio River is in the Bluegrass physiographic region. Heavy sediment loads and sewage effluent from urban centers have limited the aquatic biota in this region. Silver Creek and South Elkhorn Creek have been particularly affected and aquatic communities in these streams are dominated by organisms tolerant of low dissolved oxygen concentrations. Biological data for other streams indicate that habitat and water quality conditions are favorable for most commonly occurring aquatic organisms. 205 refs., 7 figs., 1 tab

  11. Surface characterization and cytotoxicity response of biodegradable magnesium alloys

    International Nuclear Information System (INIS)

    Magnesium alloys have raised an immense amount of interest to many researchers because of their evolution as a new kind of third generation materials. Due to their biocompatibility, density, and mechanical properties, magnesium alloys are frequently reported as prospective biodegradable implant materials. Moreover, magnesium alloys experience a natural phenomenon to biodegrade in aqueous solutions due to its corrosion activity, which is excellent for orthopedic and cardiovascular applications. However, a major concern with such alloys is fast and non-uniform corrosion degradation. Controlling the degradation rate in the physiological environment determines the success of biodegradable implants. In this investigation, three different grades of magnesium alloys: AZ31B, AZ91E and ZK60A were studied for their corrosion resistance and biocompatibility. Scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and contact angle meter are used to study surface morphology, chemistry, roughness and wettability, respectively. Additionally, the cytotoxicity of the leached metal ions was evaluated by using a tetrazolium based bio-assay, MTS. - Highlights: • Micro-textured features formed after the anodization of magnesium alloys. • Contact angle increased and surface free energy decreased by anodization. • Corrosion rate increased for anodized surfaces compared to untreated samples. • Cell viability was greater than 75% implying the cytocompatibility of Mg alloys

  12. Magnesium removal in the electrolytic zinc industry

    OpenAIRE

    Booster, J.L.

    2003-01-01

    Electrolytic zinc plants need to take measures to control the magnesium content in their process liquors, because the natural magnesium bleed does not balance the input from concentrates. Presently used methods are environmentally unfriendly (due to the production of large amounts of waste gypsum) or expensive. Therefore, an alternative process route is explored in which magnesium is removed from zinc electrolyte by selective precipitation of magnesium fluoride (sellaite). As standard applica...

  13. Solid-state rechargeable magnesium battery

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Yuyan; Liu, Jun; Liu, Tianbiao; Li, Guosheng

    2016-09-06

    Embodiments of a solid-state electrolyte comprising magnesium borohydride, polyethylene oxide, and optionally a Group IIA or transition metal oxide are disclosed. The solid-state electrolyte may be a thin film comprising a dispersion of magnesium borohydride and magnesium oxide nanoparticles in polyethylene oxide. Rechargeable magnesium batteries including the disclosed solid-state electrolyte may have a coulombic efficiency .gtoreq.95% and exhibit cycling stability for at least 50 cycles.

  14. A Search for Magnesium in Europa's Atmosphere

    OpenAIRE

    Horst, Sarah M.; Brown, Michael E.

    2013-01-01

    Europa's tenuous atmosphere results from sputtering of the surface. The trace element composition of its atmosphere is therefore related to the composition of Europa's surface. Magnesium salts are often invoked to explain Galileo Near Infrared Mapping Spectrometer spectra of Europa's surface, thus magnesium may be present in Europa's atmosphere. We have searched for magnesium emission in the Hubble Space Telescope Faint Object Spectrograph archival spectra of Europa's atmosphere. Magnesium wa...

  15. Magnesium and related low alloys

    International Nuclear Information System (INIS)

    In the first part the authors examine the comparative corrosion of commercial magnesium, of a magnesium-zirconium alloy (0,4 per cent ≤ Zr ≤ 0,7 per cent) of a ternary magnesium-zinc-zirconium alloy (0,8 per cent ≤ Zn ≤ 1,2 per cent) and of english 'Magnox type' alloys, in dry carbon dioxide-free air, in damp carbon dioxide-free air, and in dry and damp carbon dioxide, at temperatures from 300 to 600 deg. C. In the second part the structural stability of these materials is studied after annealings, of 10 to 1000 hours at 300 to 450 deg. C. Variations in grain after these heat treatments and mechanical stretching properties at room temperature are presented. Finally various creep rate and life time diagrams are given for these materials, for temperatures ranging from 300 to 450 deg. C. (author)

  16. Magnesium sulphate for fetal neuroprotection

    DEFF Research Database (Denmark)

    Bickford, Celeste D; Magee, Laura A; Mitton, Craig;

    2013-01-01

    BACKGROUND: The aim of this study was to assess the cost-effectiveness of administering magnesium sulphate to patients in whom preterm birth at ... sensitivity analyses were used to compare the administration of magnesium sulphate with the alternative of no treatment. Two separate cost perspectives were utilized in this series of analyses: a health system and a societal perspective. In addition, two separate measures of effectiveness were utilized: cases...... of cerebral palsy (CP) averted and quality-adjusted life years (QALYs). RESULTS: From a health system and a societal perspective, respectively, a savings of $2,242 and $112,602 is obtained for each QALY gained and a savings of $30,942 and $1,554,198 is obtained for each case of CP averted when magnesium...

  17. Mechanical Properties of Magnesium-Rare Earth Alloy Systems: A Review

    Directory of Open Access Journals (Sweden)

    Sravya Tekumalla

    2014-12-01

    Full Text Available Magnesium-rare earth based alloys are increasingly being investigated due to the formation of highly stable strengthening phases, activation of additional deformation modes and improvement in mechanical properties. Several investigations have been done to study the effect of rare earths when they are alloyed to pure magnesium and other Mg alloys. In this review, the mechanical properties of the previously investigated different magnesium-rare earth based binary alloys, ternary alloys and other higher alloys with more than three alloying elements are presented.

  18. Thermal spraying on the magnesium alloy AZ91

    Energy Technology Data Exchange (ETDEWEB)

    Lenz, U.; Weisheit, A.; Mordike, B.L. (Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Werkstoffkunde und Werkstofftechnik)

    1998-01-01

    The results of this investigations show, that thermal sprayed coatings can improve the surface properties of magnesium base alloys. Aluminium coatings can improve corrosion resistance, whereas wear resistance can significantly be improved with NiCrFeSiB and NiAl coatings. When materials are coated which are sensitive to contact corrosion then the density of the layer is the most important property. In this respect HVOF spaying seems to be the preferred process for producing protective coatings on magnesium substrates. (orig.)

  19. Structure evolution of AZ61 magnesium alloy in SIMA process

    Institute of Scientific and Technical Information of China (English)

    YAN Hong; ZHANG Fa-yun; JIE Xiao-ping

    2005-01-01

    The effect of prior compressive deformation, isothermal temperature and holding time on the structure of AZ61 magnesium alloy fabricated by strain-induced melt activation(SIMA) processing was investigated. The specimens were subjected under deformation ratios of 0%, 22% and 40% and various heat treatment time and temperature regions. The results indicate that the ideal technological parameters of semi-solid AZ61 alloy produced with non-dendrites are recommended as 22% (prior compressive deformation), 595 ℃ (heat treatment temperature) and 40 min(time). The as-cast AZ61 magnesium alloy isn't fit for semi-solid forming.

  20. 21 CFR 582.5434 - Magnesium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium phosphate. 582.5434 Section 582.5434 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5434 Magnesium phosphate. (a) Product. Magnesium phosphate (di- and tribasic)....

  1. 21 CFR 582.5431 - Magnesium oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium oxide. 582.5431 Section 582.5431 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5431 Magnesium oxide. (a) Product. Magnesium oxide. (b) Conditions of use. This...

  2. 21 CFR 582.5443 - Magnesium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium sulfate. 582.5443 Section 582.5443 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5443 Magnesium sulfate. (a) Product. Magnesium sulfate. (b) Conditions of use....

  3. 21 CFR 582.1431 - Magnesium oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium oxide. 582.1431 Section 582.1431 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1431 Magnesium oxide. (a) Product. Magnesium oxide. (b) Conditions of use. This substance...

  4. 21 CFR 201.71 - Magnesium labeling.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Magnesium labeling. 201.71 Section 201.71 Food and... LABELING Labeling Requirements for Over-the-Counter Drugs § 201.71 Magnesium labeling. (a) The labeling of over-the-counter (OTC) drug products intended for oral ingestion shall contain the magnesium...

  5. Magnesium, Inflammation, and Obesity in Chronic Disease

    Science.gov (United States)

    About 60% of U.S. adults do not consume the Estimated Average Intake for magnesium, but widespread pathological conditions attributed to magnesium deficiency have not been reported. However, low magnesium status has been associated with numerous pathological conditions characterized as having a chr...

  6. Microstructure and mechanical properties of selective laser melted magnesium

    International Nuclear Information System (INIS)

    The effects of laser processing parameters on the microstructure and mechanical properties of selective laser-melted magnesium were investigated. The results show that the microstructure characteristics of the laser-melted samples are dependent on the grain size of SLM magnesium. The grains in the molten zone coarsen as the laser energy density increases. In addition, the average hardness values of the molten zone decreases significantly with an increase of the laser energy densities and then decreased slowly at a relatively high laser energy density irrespective of mode of irradiation. The hardness value was obtained from 0.59 to 0.95 GPa and corresponding elastic modulus ranging from 27 to 33 GPa. The present selective laser-melted magnesium parts are promising for biomedical applications since the mechanical properties are more closely matched with human bone than other metallic biomaterials.

  7. Effects of magnesium sulfate on traumatic brain edema in rats

    Institute of Scientific and Technical Information of China (English)

    冯东福; 朱志安; 卢亦成

    2004-01-01

    Objective: To investigate the effects of magnesium sulfate on traumatic brain edema and explore its possible mechanism.Methods: Forty-eight Sprague-Dawley ( SD ) rats were randomly divided into three groups: Control, Trauma and Treatment groups. In Treatment group, magnesium sulfate was intraperitoneally administered immediately after the induction of brain trauma. At 24 h after trauma, total tissue water content and Na + , K + , Ca2 + , Mg2+ contents were measured. Permeability of blood-brain barrier (BBB)was assessed quantitatively by Evans Blue (EB) dye technique. The pathological changes were also studied.Results: Water, Na + , Ca2 + and EB contents in Treatment group were significantly lower than those in Trauma group ( P < 0. 05 ). Results of light microscopy and electron microscopy confirmed that magnesium sulfate can attenuate traumatic brain injury and relieve BBB injury.Conclusions: Treatment with MgSO4 in the early stage can attenuate traumatic brain edema and prevent BBB injury.

  8. Constraints on Weathering from Riverine Magnesium Isotope Ratios

    DEFF Research Database (Denmark)

    Wiechert, Uwe; Ullmann, Clemens Vinzenz; Meixner, Anette;

    Weathering of rocks and its impact on the atmospheric carbon budget have been calculated from chemical compositions of large rivers. Here we present chemical compositions and magnesium isotope ratios for the dissolved and suspended loads of the rivers Danube, Elbe, and Rhine, and investigate...... whether magnesium isotopes can contribute to the quantification of weathering rates in their catchments. The d26Mg of the dissolved and solid loads vary from -0.93 to -1.85 ‰ and -0.98 to +0.01 ‰ relative to the reference material DSM3, respectively. Although these rivers run through highly populated...... and industrialized regions, the d26Mg values mirror the lithologies of the catchment areas: the Danubian catchment is dominated by carbonatic lithologies and in the Danube dissolved magnesium exhibits the most negative d26Mg values between -1.85 and -1.70 ‰. The mainly siliceous catchment of the river Elbe causes...

  9. Structural, spectroscopic and biological investigation of copper oxides nanoparticles with various capping agents

    International Nuclear Information System (INIS)

    Powder composed of copper oxides nanoparticles with various capping agents has been synthesized and characterized with the use of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Polyvinyl alcohol (PVA), glycol propylene, glycerin and glycerin plus ammonia were used as capping agents. The scanning electron microscopy (SEM) studies showed that nanoparticles form agglomerates with the size from 80 to 120 nm while particles size determined from the XRD experiment was in the range from 7 to 21 nm. XPS and XRD experiments revealed that depending on capping and reducing agents used in the synthesis nanoparticles are composed of Cu2O, CuO or a mixture of them. The biological activity test performed for a selected sample where the capping agent was glycerin plus ammonia has shown promising killing/inhibiting behavior, very effective especially for Gram negatives bacteria. - Highlights: • We obtained copper oxide nanoparticles in a powder form. • Several capping agents were tested. • Structural and chemical tests showed that the main component were Cu2O and CuO. • The size of nanoparticles was in the range 7–21 nm. • Nanoparticles with glycerin and ammonia capping agent showed good antibacterial properties

  10. Engineered G-protein coupled receptors are powerful tools to investigate biological processes and behaviors

    Directory of Open Access Journals (Sweden)

    Charles D Nichols

    2009-10-01

    Full Text Available Understanding how discreet tissues and neuronal circuits function in relation to the whole organism to regulate physiological processes and behaviors is a fundamental goal of modern biological science. Powerful and important new tools in this discovery process are modified G-protein coupled receptors (GPCRs known as ‘Receptors Activated Solely by Synthetic Ligands (RASSLs,’ and ‘Designer Receptors Exclusively Activated by a Designer Drug (DREADDs.’ Collectively, these are GPCRs modified either through rational design or directed molecular evolution, that do not respond to native ligand, but functionally respond only to synthetic ligands. Importantly, the utility of these receptors is not limited to examination of the role of GPCR-coupled effector signal transduction pathways. Due to the near ubiquitous expression of GPCRs throughout an organism, this technology, combined with whole animal transgenics to selectively target expression, has the ability to regulate activity of discreet tissues and neuronal circuits through effector pathway modulation to study function and behavior throughout the organism. Advantages over other systems currently used to modify in vivo function include the ability to rapidly, selectively and reversibly manipulate defined signal transduction pathways both in short term and long term studies, and no need for specialized equipment due to convenient systemic treatment with activating ligand.

  11. Structural, spectroscopic and biological investigation of copper oxides nanoparticles with various capping agents

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, A., E-mail: ana.maria.nowak@gmail.com [A. Chelkowski Institute of Physics, University of Silesia, Katowice (Poland); Szade, J.; Talik, E.; Ratuszna, A. [A. Chelkowski Institute of Physics, University of Silesia, Katowice (Poland); Ostafin, M. [Agricultural University of Cracow, Department of Microbiology, Krakow (Poland); Peszke, J. [A. Chelkowski Institute of Physics, University of Silesia, Katowice (Poland)

    2014-06-01

    Powder composed of copper oxides nanoparticles with various capping agents has been synthesized and characterized with the use of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Polyvinyl alcohol (PVA), glycol propylene, glycerin and glycerin plus ammonia were used as capping agents. The scanning electron microscopy (SEM) studies showed that nanoparticles form agglomerates with the size from 80 to 120 nm while particles size determined from the XRD experiment was in the range from 7 to 21 nm. XPS and XRD experiments revealed that depending on capping and reducing agents used in the synthesis nanoparticles are composed of Cu{sub 2}O, CuO or a mixture of them. The biological activity test performed for a selected sample where the capping agent was glycerin plus ammonia has shown promising killing/inhibiting behavior, very effective especially for Gram negatives bacteria. - Highlights: • We obtained copper oxide nanoparticles in a powder form. • Several capping agents were tested. • Structural and chemical tests showed that the main component were Cu{sub 2}O and CuO. • The size of nanoparticles was in the range 7–21 nm. • Nanoparticles with glycerin and ammonia capping agent showed good antibacterial properties.

  12. Antitumor and biological investigation of doubly cyclometalated ruthenium(ii) organometallics derived from benzimidazolyl derivatives.

    Science.gov (United States)

    Elumalai, Palani; Jeong, Yong Joon; Park, Dae Won; Kim, Dong Hwan; Kim, Hyunuk; Kang, Se Chan; Chi, Ki-Whan

    2016-04-12

    In this study, we report the synthesis, anticancer and biological properties of three doubly cyclometalated phenylbenzimidazole derived ruthenium(ii) organometallics () and their corresponding three organic ligands. The structures of were fully characterized by various analytical techniques, and the meso stereoisomer of the doubly cyclometalated ruthenacycle was unambiguously confirmed by single crystal X-ray diffraction. The anticancer effects of the newly synthesized compounds were tested against selected human cancer cell lines AGS (gastric carcinoma), SK-hep-1 (hepatocellular carcinoma), and HCT-15 (colorectal carcinoma). The growth inhibitory effects of ruthenacycles on cancer cells were found to be considerably more effective against the abovementioned cancer cells than the reference drug oxaliplatin. Compound exhibited a more specific effect on the AGS cells. Gene-fishing and ELISA array were performed to analyze the target genes and cytokine secretion by . As a result, a significant reduction was observed in RPS21 by . Moreover, increased the secretion of cytokines such as IFNγ in macrophages and reduced the release of cytokines such as rantes and IGF-1. These results show that could be a very good anticancer drug through the regulation of the RPS21 gene and cytokines. PMID:26974823

  13. Neutron Reflectometry Investigations of the Interaction of DNA-PAMAM Dendrimers with Model Biological Membranes

    International Nuclear Information System (INIS)

    The systemic delivery of DNA for gene therapy requires control of DNA compaction by an agent, such a lipid, surfactant or a polymer (e.g. cationic dendrimers) as well as understanding of how this complex interacts with a biological membrane. Poly (amido amine) (PAMAM) dendrimers have been reported to be a promising synthetic gene-transfection agent. We have studied the structure of the complexes formed between DNA and PAMAM dendrimers with SANS, dynamic light scattering and cryo-TEM. Here we noted that the structure of the complex formed strongly depends on the generation of the dendrimer. The results of the adsorption of generation 2 (G2) and 4 (G4) PAMAM dendrimers to surface deposited bilayers, consisting of palmitoyl oleoyl phosphatidyl choline on silicon surface, have been studied using neutron reflectometry (NR). The NR data shows that the dendrimers are able to penetrate the bilayer. However, the complex is less able to penetrate the bilayer, but rather stays on the top of the bilayer. The dendrimers appear slightly flattened on the surface in comparison with their size in bulk as determined by light scattering. We will also report on the interfacial behavior of the DNA-PAMAM complexes at other types of studies of interfaces, important for biomedical applications, where NR has allowed us to determine the layer structure and composition. (author)

  14. Magnesium treatment palliates noise-induced behavioral deficits by normalizing DAergic and 5-HTergic metabolism in adult male rats.

    Science.gov (United States)

    Haider, Saida; Sadir, Sadia; Naqvi, Fizza; Batool, Zehra; Tabassum, Saiqa; Khaliq, Saima; Anis, Lubna; Sajid, Irfan; Haleem, Darakhshan J

    2016-08-01

    Magnesium (Mg) is the fourth most abundant biological mineral essential for good health. Neuroprotective, anxiolytic and antidepressant effects of magnesium following stress and brain injuries are well established. In present study, we analyzed the protective effects of magnesium in rats exposed to sub-chronic noise stress. Magnesium Chloride (MgCl2, 100 mg/kg) was administered intraperitoneally once daily for 15 days prior exposure to noise stress. Rats were exposed to noise stress for 4 h after administration of magnesium for 15 days. At the end of treatment behavioral alterations were assessed. Animals were decapitated following behavioral testing and the brains were dissected out for neurochemical estimations by HPLC-EC. Improvement in noise-induced memory deficits as assessed by novel object recognition (NOR) test and elevated plus maze (EPM) test was found in magnesium treated rats. This improvement in noise-induced behavioral deficits following treatment with magnesium may be attributed to a significant decrease (p < 0.01) in dopamine (DA) and serotonin (5-hydroxytryptamine; 5-HT) turnover as compared to control rats observed in present work. These results suggest that treatment with magnesium can attenuate the noise-induced deficits and may be used as a therapy against noise-induced neurodegeneration. Moreover an adequate amount of magnesium in daily diet may help to develop the ability to resist against or cope up with stressful conditions encountered in daily life. PMID:26928203

  15. Improvement approaches of hydrogen sorption process in magnesium

    Directory of Open Access Journals (Sweden)

    E. David

    2006-04-01

    Full Text Available Purpose: of this paper is to study the possibility of use of magnesium hydrides as energy carriers. The hydride, MgH2 , can store up to 7.6 wt. % of hydrogen,but there are three problems with the application of pure Mg: (a the rate at which hydrogen absorbs and desorbs is too low;(b the hydrogen molecules do not readily dissociate at the surface of Mg to generate the hydrogen atoms that diffuse into metal; (c the hydrogen desorption takes place at high temperature.Design/methodology/approach: as magnesium can be use as hydrogen storage material is to improve hydrogenation / dehydrogenation process by allyoing with other metals such as Ni and Al. Nanocrystalline magnesium based alloys were prepared by ball milling. The milling was carried out with a planetary mill and the effect of Ni and Al addition was investigated by means of thermogravimetry analysis (TGA, X-ray diffraction analysis (XRD and scanning electronic microscopy (SEM.Findings: Through this study it was found that the above problems could be solve by forming of small magnesium and magnesium based alloy crystals using ball milling technique. The addition of small amount of nickel , can catalyse the bond breaking / formation of the hydride event at the surface. The alloying with aluminium was shown that the thermodynamical properties -lower desorption temperatures and kinetic of hydrogen sorption process were improved along with improved resistance to O2 contamination.Practical implications: The inclusion of Ni and Al into magnesium by mechanical ball milling leads to lower the hydrogen desorption temperature from hydride and kinetic improvement of hydrogen sorption process in magnesium. Addition of Ni and Al to Mg also represents new approach of improvement of materials based on light metals, that can provide promising results for the hydrogen storage applications.Originality/value: The results presented in this paper contributes to elucidate the hydrogen sorption process in magnesium

  16. 75 FR 59935 - Investigational New Drug Safety Reporting Requirements for Human Drug and Biological Products and...

    Science.gov (United States)

    2010-09-29

    ... negative impact on the conduct of clinical trials. In addition to sharply increasing the number of reports... a negative impact on clinical trials, IRBs, investigators, signal detection, and drug labeling... Analysis of Impacts and Paperwork Burden Estimates IV. Legal Authority V. Environmental Impact VI....

  17. Biological investigations of the thermal discharge area of the Oskarshamn nuclear power plant during the eighties

    International Nuclear Information System (INIS)

    The paper summarizes the investigations of the environmental impacts of the cooling water discharges. The productivity of aquatic organisms and fishes has increased. The frequency of parasitic diseases in eel is high. Fishes have shown reproductive disorders. (K.A.E.)

  18. Antithrombogenic investigation and biological behavior of cultured human umbilical vein endothelial cells on Ti-O film

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Our previous research results have shown that the Ti-O films with appropriate characteristics possess great potentials for biomaterials application. In this paper, using plasma immersion ion implantation and deposition (PIII-D), titanium oxide thin films are fabricated onto silicon wafer. The antithrombogenesis of films is evaluated in vitro through the platelet adhesion investigation. The biological behavior of human umbilical vein endothelial cells (HUVEC) on the film surface is investigated in vitro by endothelial cell (EC) culture. Our results reveal that the crystalline Ti-O films exhibit attractive blood compatibility. The in vitro HUVEC-cultured investigation of Ti-O film surface has justified that the biological behavior of HUVECs on different structure surfaces is significantly different. The adherence, growth and proliferation of HUVECs to the crystalline Ti-O film surface are in order, by forming a perfect single layer, preserving the natural original shape and displaying the cobblestone road metal rank, and obviously superior to that on the amorphous Ti-O film surface. According to our study, the crystalline Ti-O film, with proper microstructure, is helpful for seeding Ecs and can be used as a functional surface for the adherence and growth of ECS.

  19. The initial oxidation of magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Kurth, M.

    2004-07-01

    Pure Magnesium samples have been oxidised in an UHV chamber under controlled conditions. Pressure range was 10{sup -10} Torr to 10{sup -7} Torr, temperature range was 273 K to 435 K. The samples have then been investigated with XPS, Ellipsometry and HERDA. Additionally, furnace oxidations at 750 Torr and 673 K have been carried out and investigated with XPS. From the XPS measurements data concerning layer thickness, composition, oxidation state and binding state have been gained. The ellipsometrie measurements yielded additional data concerning layer thickness as well as the size of the band gap of the developing oxide. With the HERDA measurements, the oxygen content within the oxide layer has been determined yielding additional information about composition and layer thickness. The layer thickness as a function of time have then been modelled with a kinetic growth model of Fromhold and Cook. For the refinement of the XPS data concerning layer thickness and composition, the pronounced plasmon excitations that occur in magnesium have been determined with two different procedures which have been developed in the methodical part of this work. The layer thickness and composition values have thus been corrected. Results: Two oxidation stages could be identified: a strong increase for the first few Langmuirs (1L = 1s x 10{sup -6} Torr), followed by a saturation'' region which was about 1.2 nm to 1.5 nm in magnitude. XPS and ellipsometry results have thereby been in very good agreement. The composition of the developing oxide showed a clear deviation from stoichiometric MgO, mainly caused by an oxygen deficiency; this deficiency has also been confirmed with the HERDA measurements. The Mg/O ratio as a function of layer thickness showed a continous decay starting from very high values for the thinnest layers (>{proportional_to}2.5) down to a saturation value of about 1.4, even for larger layer thicknesses gained with the furnace oxidations. The determination of

  20. Preparing for and implementing the UN secretary-general's mechanism on alleged use investigation for biological weapons

    International Nuclear Information System (INIS)

    The United Nations Global Counter-Terrorism Strategy was adopted by the UN General Assembly in September 2006. Preventing and responding to attacks using WMD were identified amongst the key areas of activities covered by the strategy. The Secretary-General's mechanism to carry out prompt investigations in response to allegations brought to his attention concerning the possible use of chemical and bacteriological (biological) and toxin weapons was developed in the late 1980s. Triggered by a request from any member State, the Secretary-General is authorized to launch an investigation including dispatching a fact-finding team to the site of the alleged incident(s) and to report to all UN Member States. This is to ascertain in an objective and scientific manner facts of alleged violations of the 1925 Geneva Protocol, which bans the use of chemical and biological weapons. Member States encouraged the Secretary-General in September 2006 to update the roster of experts and laboratories, as well as the technical guidelines and procedures, available to him for the timely and efficient investigation of alleged use. The roster of experts and laboratories and the guidelines and procedures constitute the key elements of the special mechanism available to the Secretary-General for investigation of reports by Member States of alleged use of chemical, biological and toxin weapons. The Office for Disarmament Affairs has been working with Member States since March 2007 to update the roster of experts and laboratories and the technical appendices of the guidelines and procedures so that they fully correspond with the rapid and substantial developments that have occurred in the biological area since the 1980s and also to take into account the fact that an Organization for the Prohibition of Chemical Weapons (OPCW) has since been established. Currently, the roster of experts and laboratories has been updated and includes experts from more than 50 countries. The information available in

  1. Magnesium Diboride Current Leads

    Science.gov (United States)

    Panek, John

    2010-01-01

    A recently discovered superconductor, magnesium diboride (MgB2), can be used to fabricate conducting leads used in cryogenic applications. Dis covered to be superconducting in 2001, MgB2 has the advantage of remaining superconducting at higher temperatures than the previously used material, NbTi. The purpose of these leads is to provide 2 A of electricity to motors located in a 1.3 K environment. The providing environment is a relatively warm 17 K. Requirements for these leads are to survive temperature fluctuations in the 5 K and 11 K heat sinks, and not conduct excessive heat into the 1.3 K environment. Test data showed that each lead in the assembly could conduct 5 A at 4 K, which, when scaled to 17 K, still provided more than the required 2 A. The lead assembly consists of 12 steelclad MgB2 wires, a tensioned Kevlar support, a thermal heat sink interface at 4 K, and base plates. The wires are soldered to heavy copper leads at the 17 K end, and to thin copper-clad NbTi leads at the 1.3 K end. The leads were designed, fabricated, and tested at the Forschungszentrum Karlsruhe - Institut foer Technische Physik before inclusion in Goddard's XRS (X-Ray Spectrometer) instrument onboard the Astro-E2 spacecraft. A key factor is that MgB2 remains superconducting up to 30 K, which means that it does not introduce joule heating as a resistive wire would. Because the required temperature ranges are 1.3-17 K, this provides a large margin of safety. Previous designs lost superconductivity at around 8 K. The disadvantage to MgB2 is that it is a brittle ceramic, and making thin wires from it is challenging. The solution was to encase the leads in thin steel tubes for strength. Previous designs were so brittle as to risk instrument survival. MgB2 leads can be used in any cryogenic application where small currents need to be conducted at below 30 K. Because previous designs would superconduct only at up to 8 K, this new design would be ideal for the 8-30 K range.

  2. Development of in vitro models for investigating spatially fractionated irradiation: physics and biological results

    Science.gov (United States)

    Blockhuys, S; Vanhoecke, B; Paelinck, L; Bracke, M; DeWagter, C

    2009-03-01

    We present different in vitro experimental models which allow us to evaluate the effect of spatially fractionated dose distributions on metabolic activity. We irradiated a monolayer of MCF-7/6 human breast cancer cells with a steep and a smooth 6 MV x-ray dose gradient. In the steep gradient model, we irradiated the cells with three separate small fields. We also developed two smooth gradient models. In the first model, the cells are cultured in a T25 flask and irradiated with a smooth dose gradient over the length of the flask, while in the second one, the cells are cultured in a 96-well plate and also irradiated over the length of the plate. In an attempt to correlate the spatially fractionated dose distributions with metabolic activity, the effect of irradiation was evaluated by means of the MTT assay. This assay is used to determine the metabolic activity by measuring the amount of formazan formed after the conversion of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) by cellular dehydrogenases. The results obtained with our different models suggest a dose-specific effect on metabolic activity, characterized by an increased formazan optical density occurring in the dose range 1.0-4.0 Gy in the steep dose gradient model and in the dose ranges 4.2-6.5 Gy and 2.3-5.1 Gy in the two smooth dose gradient models. The corresponding times for maximal formazan accumulation were 5-7 days in the steep dose gradient model and day 9-13 and day 9-11 in the smooth dose gradient models. Altogether, our results suggest that the MTT assay may be used as a biological dose-response meter to monitor the radiotherapeutic effectiveness.

  3. Limitations of the scalp-hair biologic monitor in assessing selenium status in epidemiological investigations

    International Nuclear Information System (INIS)

    Scalp hair is routinely used to assess exposure to toxic trace elements and nutritional status of some required trace elements. The advantages and disadvantages of hair as a biologic monitor have been comprehensively discussed in the literature for many years. Among the concerns is distinguishing between exogenous and endogenous contributions. Nested in this issue is the longitudinal distribution of a trace element along the hair strand. The typical observation for many elements of interest is that the element concentration increases from the root end to the distal end; and this is attributed to continuing contamination from exogenous sources. In this study we used neutron activation analysis to measure 14 trace elements in 6 mm segments of full-length scalp hair from three healthy members of the same household having light-urban environmental exposure. To extend the data set for selenium, we included three adult female subjects with longer than average scalp hair. From these trace-element concentrations we calculated the root-to-distal end ratios as a profile diagnostic of trace-element distributions. Ratios fall into three diagnostic categories, >1, ∼1, and 1, Zn and S have R ∼ 1, and the remaining 11 elements all have R I > Hg ∼ Au ∼ Mg ∼ Mn ∼ Sb ∼ Ca > Cu > Al ∼ Ag. RSe is greater than 1 and increases with hair length (P 0.02) corresponding to a continuous longitudinal loss of Se in stark and puzzling contrast to the other elements measured. An analogous loss of Se in the nail monitor was not observed leading us to conclude that the nail is less prone to misclassification of selenium status in epidemiological studies. (author)

  4. Bio-templated CdSe quantum dots green synthesis in the functional protein, lysozyme, and biological activity investigation

    International Nuclear Information System (INIS)

    Bifunctional fluorescence (CdSe Quantum Dots) – protein (Lysozyme) nanocomposites were synthesized at room temperature by a protein-directed, solution-phase, green-synthetic method. Fluorescence (FL) and absorption spectra showed that CdSe QDs were prepared successfully with Lyz. The average particle size and crystalline structure of QDs were investigated by high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD), respectively. With attenuated total reflection-fourier transform infrared (ATR-FTIR) spectra and thermogravimetric (TG) analysis, it was confirmed that there is interaction between QDs and amide I, amide II groups in Lyz. FL polarization was measured and FL imaging was done to monitor whether QDs could be responsible for possible changes in the conformation and activity of Lyz. Interestingly, the results showed Lyz still retain the biological activity after formation of QDs, but the secondary structure of the Lyz was changed. And the advantage of this synthesis method is producing excellent fluorescent QDs with specifically biological function. -- Highlights: ► Lysozyme-directed green synthesis of CdSe quantum dots. ► Lysozyme still retain the biological activity after formation of CdSe. ► The method is the production of fluorescent QDs with highly specific and functions.

  5. From track structure to biological endpoints: models, codes and MC simulations to investigate radiation action and damage formation

    International Nuclear Information System (INIS)

    The investigation of the action of ionising radiation on biological structures requires a detailed analysis of the various stages underlying damage induction and evolution. In order to take into account the stochastic aspects characterising the process of interest ab initio models and MC simulation codes are required, which start from the physical track structure and follow its time evolution, taking into account the various levels of organisation of the biological targets (DNA, chromosomes etc.). Representative examples of the activities in this area of the Universities of Milan and Pavia will be presented, focusing on the development of models aimed: a) to better understand the action mechanisms of ionising radiation, in the framework of the EC project Low Dose Risk Models coordinated by the GSF Institute of munich; b) to study the induction of chromosome aberrations and their possible use as biomarkers, mainly in the framework of the INFN experiment DOSBI, developed in collaboration with the University of Naples; c) to provide basic data for applicative tools developed for hadron therapy and space radiation protection, in the framework of the INFN projects ATER.FIBI and FLUKA and the ASI (Italian Space Agency) project Influence of the shielding in the space radiation biological effectiveness

  6. Hydrogen Sorption Performance of Pure Magnesium during Continued Cycling

    DEFF Research Database (Denmark)

    Vigeholm, B.; Kjøller, John; Larsen, B.;

    1983-01-01

    Preliminary investigations of the hydrogen absorption - desorption by commercially pure magnesium powder under continuous operation show little or no reduction in hydrogen capacity up to 70 cycles and high temperature exposure exceeding 1200 h. Absorption was studied at 260°–425°C and hydrogen...

  7. Biological investigations off the Oskarshamn nuclear power station during the 1980's

    International Nuclear Information System (INIS)

    The Oscarshamn power station consists of three nuclear reactors, of which the first came into production in 1972 and the last in 1985. The power station uses large volumes of cooling-water; altogether 100 m3/s is heated 10 degrees C. During the 1970's, the investigations of the ecological effects of the use of cooling-water had a wide coverage, whereas during the 1980's, the years treated here, the investigations have mainly been concentrated on fish and bottom fauna. The temperature increase stimulates growth of many organisms and causes attraction. The cooling-water plume and the counter-currents it causes increase the transports of nutrients. The concentration of nutrients in different ways contributes to increased production further up in the food chains and strengthens the attraction of fish. The losses of fish in the cooling system have been relatively small. The parasitization frequency of eels in the receiving bay is extremely high, but otherwise there have been no abnormal disease or parasite attacks. Disturbances to the reproduction of fish in the heated water are present. The importance of this, particularly for surrounding areas, should be investigated within the continued monitoring. (authors)

  8. Studies on the extraction of nuclear pure magnesium from sea bittern

    International Nuclear Information System (INIS)

    This investigation is devoted to the extraction of nuclear grade magnesium from sea bittern. It comprises three main parts: The first is pertaining to examine the effect of bittern evaporation on both its physical and chemical properties. It a second part , a brief comparative study on magnesium extraction from bittern by use of lime, dolime, solvent extraction and precipitation with ammonia solution and gas as also with ammonia carbon dioxide gas mixture, has been attempted. The precipitation approach by ammonia-carbon dioxide mixture was the mean adopted. A careful systematic examination of various parameters affecting precipitation was undertaken on economic basis. Recovery and purity of magnesium hydroxide, have been taken into account by the study of magnesium concentration in the bittern, its temperature, flow rate of precipitant, ... etc. Since the produced magnesium compound contained 100 ppm of boron, it has to be minimized to less than 1 ppm to agree with the nuclear specifications

  9. Formation and characterization of magnesium bisozonide and carbonyl complexes in solid argon.

    Science.gov (United States)

    Wang, Guanjun; Gong, Yu; Zhang, Qingqing; Zhou, Mingfei

    2010-10-14

    The reactions of magnesium atoms with dioxygen and dioxygen/carbon monoxide mixture have been investigated by matrix isolation infrared absorption spectroscopy. Magnesium atoms react with dioxygen in solid argon to form the inserted MgO(2) molecules under UV excitation, which were previously characterized. Annealing allows the dioxygen molecules to diffuse and to react with MgO(2) and form the magnesium bisozonide complex, Mg(O(3))(2), which is proposed to be coordinated by two argon atoms in solid argon matrix. The Mg(O(3))(2)(Ar)(2) complex is characterized to have two equivalent side-on bonded ozonide ligands with a D(2h) symmetry. The coordinated argon atoms can be replaced by carbon monoxide to give the magnesium bisozonide dicarbonyl complex, Mg(O(3))(2)(CO)(2), a neutral magnesium carbonyl complex with CO binding to the Mg(2+) center. PMID:20857987

  10. The Effect of Ultrafine Magnesium Hydroxide on the Tensile Properties and Flame Retardancy of Wood Plastic Composites

    OpenAIRE

    Zhiping Wu; Na Hu; Yiqiang Wu; Shuyun Wu; Zu Qin

    2014-01-01

    The effect of ultrafine magnesium hydroxide (UMH) and ordinary magnesium hydroxide (OMH) on the tensile properties and flame retardancy of wood plastic composites (WPC) were investigated by tensile test, oxygen index tester, cone calorimeter test, and thermogravimetric analysis. The results showed that ultrafine magnesium hydroxide possesses strengthening and toughening effect of WPC. Scanning electron micrograph (SEM) of fracture section of samples provided the positive evidence that the ten...

  11. Characteristics of tetrahydrofuran-based electrolytes with magnesium alkoxide additives for rechargeable magnesium batteries

    Science.gov (United States)

    Kim, In-Tae; Yamabuki, Kazuhiro; Sumimoto, Michinori; Tsutsumi, Hiromori; Morita, Masayuki; Yoshimoto, Nobuko

    2016-08-01

    The electrochemical behavior of magnesium (Mg) metal was investigated in tetrahydrofuran (THF)-based solutions containing magnesium bromide (MgBr2) and/or magnesium ethoxide (Mg(OEt)2). THF solutions containing a single solute, MgBr2 or Mg(OEt)2, show no visible faradaic current based on Mg deposition and/or dissolution. However, the electrolyte system containing both solutes, MgBr2 + Mg(OEt)2/THF, gives a reversible current response of Mg deposition and dissolution. The ionic structure of the electrolyte system containing the binary solute was examined by infrared (IR) spectroscopy and density functional theory (DFT) calculations. It was confirmed that MgBr2 and Mg(OEt)2 are coordinated (solvated) with THF molecules to form an EtOsbnd Mgsbnd Br·4THF complex. The DFT calculations also suggest the possible formation of μ-complexes for the MgBr2/Mg(OEt)2 binary system in THF. The voltammetric responses at the Pt electrode indicate low overpotential and high coulombic efficiency for Mg deposition and dissolution in THF-based solutions containing suitable molar ratios of MgBr2 and Mg(OEt)2. The constant-current charge-discharge cycling of Mg in MgBr2 + Mg(OEt)2/THF electrolyte also shows low overpotential and good cyclability over 300 cycles.

  12. Addition of senna improves quality of colonoscopy preparation with magnesium citrate

    Institute of Scientific and Technical Information of China (English)

    Stergios Vradelis; Evangelos Kalaitzakis; Yalda Sharifi; Otto Buchel; Satish Keshav; Roger W Chapman; Barbara Braden

    2009-01-01

    AIM: To prospectively investigate the effectiveness and patient's tolerance of two low-cost bowel cleansing preparation protocols based on magnesium citrate only or the combination of magnesium citrate and senna. METHODS: A total of 342 patients who were referred for colonoscopy underwent a colon cleansing protocol with magnesium citrate alone ( n = 160) or magnesium citrate and senna granules ( n = 182). The colonoscopist rated the overall efficacy of colon cleansing using an established score on a 4-point scale. Patients were questioned before undergoing colonoscopy for side effects and symptoms during bowel preparation. RESULTS: The percentage of procedures rescheduled because of insufficient colon cleansing was 7% in the magnesium citrate group and 4% in the magnesium citrate/senna group ( P = 0.44). Adequate visualization of the colonic mucosa was rated superior under the citramag/senna regimen ( P = 0.004). Both regimens were well tolerated, and did not significantly differ in the occurrence of nausea, bloating or headache. However, abdominal cramps were observed more often under the senna protocol (29.2%) compared to the magnesium citrate only protocol (9.9%, P < 0.0003). CONCLUSION: The addition of senna to the bowel preparation protocol with magnesium citrate significantly improves the cleansing outcome.

  13. Synthesis of Environmentally Friendly Magnesium Linoleate Detergent

    Institute of Scientific and Technical Information of China (English)

    Wang Yonglei; Li Haiyun; Fang Hongxia; Ni Zhifei; Zhao Lele

    2014-01-01

    This paper mainly covers a method for preparing a highly alkaline magnesium linoleate solution with a total base number (TBN) value of 328 mg KOH/g using linoleic acid as the biodegradable raw material, which can substitute for traditional lubricant detergents as an environmentally friendly detergent. Reaction conditions, including the molar ratio of magnesium oxide to linoleic acid, the molar ratio of methanol to magnesium oxide, the carbonation temperature, the molar ratio of water to magnesium oxide, the lfow rate of CO2 gas and the duration for injection of CO2 to magnesium oxide sys-tem, were optimized.

  14. Physicochemical and Biological Investigation of Different Structures of Carbon Coatings Deposited onto Polyurethane

    Directory of Open Access Journals (Sweden)

    Witold Kaczorowski

    2016-01-01

    Full Text Available The aim of this study was to examine the thrombogenic properties of polyurethane that was surface modified with carbon coatings. Physicochemical properties of manufactured coatings were investigated using transmission electron microscopy (TEM, atomic force microscopy (AFM, X-ray Photoelectron Spectroscopy (XPS, Raman spectroscopy and contact angle measurement methods. Samples were examined by the Impact-R method evaluating the level of platelets activation and adhesion of particular blood cell elements. The analysis of antimicrobial resistance against E. coli colonization and viability of endothelial cells showed that polyurethane modified with use of carbon layers constituted an interesting solution for biomedical application.

  15. Phytochemical and Biological Investigation of Two Diplotaxis Species Growing in Tunisia: D. virgata & D. erucoides

    Directory of Open Access Journals (Sweden)

    Nizar Ben Salah

    2015-10-01

    Full Text Available A phytochemical investigation of Diplotaxis virgata D.C. and D. erucoides (L. D.C. (Brassicaceae offered to the isolation of two new flavonoids isorhamnetin-3-O-α-l-glucopyranoside (1 and rhamnetin-3,3ʹ-di-O-β-d-glucopyranoside (2, respectively. Their structures have been elucidated from the extended spectroscopic methods, including 1D- and 2D-NMR, UV and mass spectrometry analysis and by comparison with literature data. The fatty acid composition of the hexane extracts of the two species was also investigated by using GC-MS. The antioxidant activity of ethanol, ethyl acetate, n-butanol extracts and the isolated compounds from the two species was evaluated using DPPH and ABTS+ scavenging assays. All the tested samples showed an efficient radical scavenging ability, with IC50 values ranging from 16–40 µg/mL for the DPPH and from 17–44 µg/mL for the ABTS+ assays. In addition, the antibacterial activity of the prepared extracts and compounds 1 and 2, determined by well diffusion agar method against two Gram positive and five Gram negative bacteria, was evaluated and the results showed significant effects against all strains used.

  16. Investigation of the effect of culture type on biological hydrogen production from sugar industry wastes

    International Nuclear Information System (INIS)

    The bio-hydrogen generation potential of sugar industry wastes was investigated. In the first part of the study, acidogenic anaerobic culture was enriched from the mixed anaerobic culture (MAC) through acidification of glucose. In the second part of the study, glucose acclimated acidogenic seed was used, along with the indigenous microorganisms, MAC, 2-bromoethanesulfonate treated MAC and heat treated MAC. Two different COD levels (4.5 and 30 g/L COD) were investigated for each culture type. Reactors with initial COD concentration of 4.5 g/L had higher H2 yields (20.3-87.7 mL H2/g COD) than the reactors with initial COD concentration of 30 g/L (0.9-16.6 mL H2/g COD). The 2-bromoethanesulfonate and heat treatment of MAC inhibited the methanogenic activity, but did not increase the H2 production yield. The maximum H2 production (87.7 mL H2/g COD) and minimum methanogenic activity were observed in the unseeded reactor with 4.5 g/L of initial COD.

  17. Phytochemical and Biological Investigation of Two Diplotaxis Species Growing in Tunisia: D. virgata & D. erucoides.

    Science.gov (United States)

    Salah, Nizar Ben; Casabianca, Hervé; Jannet, Hichem Ben; Chenavas, Sophie; Sanglar, Corinne; Fildier, Aurélie; Bouzouita, Nabiha

    2015-01-01

    A phytochemical investigation of Diplotaxis virgata D.C. and D. erucoides (L.) D.C. (Brassicaceae) offered to the isolation of two new flavonoids isorhamnetin-3-O-α-l-glucopyranoside (1) and rhamnetin-3,3'-di-O-β-d-glucopyranoside (2), respectively. Their structures have been elucidated from the extended spectroscopic methods, including 1D- and 2D-NMR, UV and mass spectrometry analysis and by comparison with literature data. The fatty acid composition of the hexane extracts of the two species was also investigated by using GC-MS. The antioxidant activity of ethanol, ethyl acetate, n-butanol extracts and the isolated compounds from the two species was evaluated using DPPH and ABTS⁺ scavenging assays. All the tested samples showed an efficient radical scavenging ability, with IC50 values ranging from 16-40 µg/mL for the DPPH and from 17-44 µg/mL for the ABTS⁺ assays. In addition, the antibacterial activity of the prepared extracts and compounds 1 and 2, determined by well diffusion agar method against two Gram positive and five Gram negative bacteria, was evaluated and the results showed significant effects against all strains used. PMID:26445040

  18. Can an attribution assessment be made for Yellow Rain? Systematic reanalysis in a chemical-and-biological-weapons use investigation.

    Science.gov (United States)

    Katz, Rebecca; Singer, Burton

    2007-03-01

    In intelligence investigations, such as those into reports of chemical- or biological-weapons (CBW) use, evidence may be difficult to assemble and, once assembled, to weigh. We propose a methodology for such investigations and then apply it to a large body of recently declassified evidence to determine the extent to which an attribution can now be made in the Yellow Rain case. Our analysis strongly supports the hypothesis that CBW were used in Southeast Asia and Afghanistan in the late 1970s and early 1980s, although a definitive judgment cannot be made. The proposed methodology, while resource-intensive, allows evidence to be assembled and analyzed in a transparent manner so that assumptions and rationale for decisions can be challenged by external critics. We conclude with a discussion of future research directions, emphasizing the use of evolving information-extraction (IE) technologies, a sub-field of artificial intelligence (AI). PMID:18208344

  19. Magnetic core/shell nanoparticle thin films deposited by MAPLE: Investigation by chemical, morphological and in vitro biological assays

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, R., E-mail: rodica.cristescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Popescu, C.; Socol, G.; Iordache, I.; Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Mihaiescu, D.E.; Grumezescu, A.M. [Faculty of Applied Chemistry and Materials Science, ' Politehnica' University of Bucharest, 1-7 Polizu Street, 011061 Bucharest (Romania); Balan, A.; Stamatin, I. [University of Bucharest, 3Nano-SAE Research Center, PO Box MG-38, Bucharest-Magurele (Romania); Chifiriuc, C. [Faculty of Biology, University of Bucharest, Microbiology Immunology Department, Aleea Portocalilor 1-3, Sector 5, 77206 Bucharest (Romania); Bleotu, C. [Stefan S. Nicolau Institute of Virology, 285 Mihai Bravu, 030304 Bucharest (Romania); Saviuc, C.; Popa, M. [Faculty of Biology, University of Bucharest, Microbiology Immunology Department, Aleea Portocalilor 1-3, Sector 5, 77206 Bucharest (Romania); Chrisey, D.B. [Rensselaer Polytechnic Institute, School of Engineering, Departments of Materials Science and Biomedical Engineering, Troy, 12180-3590, NY (United States)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer We deposit magnetic Fe{sub 3}O{sub 4}/oleic acid/cephalosporin nanoparticle thin films by MAPLE. Black-Right-Pointing-Pointer Thin films have a chemical structure similar to the starting material. Black-Right-Pointing-Pointer Cephalosporins have an additive effect on the grain size and induce changes in grain shape. Black-Right-Pointing-Pointer MAPLE can be used to develop novel strategies for fighting medical biofilms associated with chronic infections. - Abstract: We report on thin film deposition of nanostructured Fe{sub 3}O{sub 4}/oleic acid/ceftriaxone and Fe{sub 3}O{sub 4}/oleic acid/cefepime nanoparticles (core/shell/adsorption-shell) were fabricated by matrix assisted pulsed laser evaporation (MAPLE) onto inert substrates. The thin films were characterized by profilometry, Fourier transform infrared spectroscopy, atomic force microscopy, and investigated by in vitro biological assays. The biological properties tested included the investigation of the microbial viability and the microbial adherence to the glass coverslip nanoparticle film, using Gram-negative and Gram-positive bacterial strains with known antibiotic susceptibility behavior, the microbial adherence to the HeLa cells monolayer grown on the nanoparticle pellicle, and the cytotoxicity on eukaryotic cells. The proposed system, based on MAPLE, could be used for the development of novel anti-microbial materials or strategies for fighting pathogenic biofilms frequently implicated in the etiology of biofilm associated chronic infections.

  20. LOW DOSE MAGNESIUM SULPHATE REGIME FOR ECLAMPSIA

    Directory of Open Access Journals (Sweden)

    Bangal V

    2009-09-01

    Full Text Available Pre- eclampsia is one of the commonest medical complications seen during pregnancy. It contributes significantly to maternal and perinatal morbidity and mortality. Dr.J.A.Pritchard in 1955, introduced magnesium sulphate for control of convulsions in eclampsia and is used worldwide. Considering the low body mass index of indian women, a low dose magnesium sulphate regime has been introduced by some authors. Present study was carried out at tertiary care centre in rural area. Fifty cases of eclampsia were randomly selected to find out the efficacy of low dose magnesium sulphate regime to control eclamptic convulsions. Maternal and perinatal outcome and magnesium toxicity were analyzed. It was observed that 86% cases responded to initial intravenous dose of 4 grams of 20% magnesium sulphate . Eight percent cases, who got recurrence of convulsion, were controlled by additional 2 grams of 20% magnesium sulphate. Six percent cases required shifting to standard Pritchard regime, as they did not respond to low dose magnesium sulphate regime. The average total dose of magnesium sulphate required for control of convulsions was 20 grams ie. 54.4% less than that of standard Pritchard regime. The maternal and perinatal morbidity and mortality in the present study werecomparable to those of standard Pritchard regime. The study did not find a single case of magnesium related toxicity with low dose magnesium sulphate regime. Low dose magnesium sulphate regime was found to be safe and effective in eclampsia.

  1. Experimental observation and investigation of reactor Cs-137 isotope deactivation in biological cells

    International Nuclear Information System (INIS)

    Complete text of publication follows. The problem of natural accelerated deactivation of radioactive waste (including deactivation in environmental) is studied. In the work the process of direct controlled deactivation of water mixture of selected different longlived radioactive isotopes in growing microbiological cultures has been studied. The process was connected with transmutation of long-lived active nuclei to non-radioactive isotopes during growth and metabolism of special microbiological MCT ('microbial catalyst-transmutator'). The MCT is the special granules that include: concentrated biomass of metabolically active microorganisms, sources of carbon and energy, phosphorus, nitrogen, etc., and gluing substances that keep all components in the form of granules stable in water solutions for a long period of time at any external conditions. The base of the MCT is microbe syntrophin associations of thousands different microorganism kinds that are in the state of complete symbiosis. These microorganisms appertain to different physiological groups that represent practically the whole variety of the microbe metabolism and relevantly all kinds of microbe accumulation mechanisms. The state of complete symbiosis of the syntrophin associations results on the possibility of maximal adaptation of the microorganisms' association to any external conditions change. The mechanism of nuclear transmutation in growing biological system is described in details in the book. The research has been carried out on the basis of the same distilled water that contained different long-lived reactor isotopes (e.g., Eu154, Eu155, Cs137, Am241). In our experiments 8 identical closed glass flasks with 10 ml of the same active water in each were used. The 'microbial catalyst-transmutator' was placed in 7 glass flasks. In six different flasks different pure K, Ca, Mg, Na, Fe and P salts as single admixture were added to the active water. These chemical elements are vitally necessary for any

  2. A Marine Sulfate-Reducing Bacterium Producing Multiple Antibiotics: Biological and Chemical Investigation

    Directory of Open Access Journals (Sweden)

    Xiaoliang Wang

    2009-07-01

    Full Text Available A marine sulfate-reducing bacterium SRB-22 was isolated by means of the agar shake dilution method and identified as Desulfovibrio desulfuricans by morphological, physiological and biochemical characteristics and 16S rDNA analysis. In the bioassay, its extract showed broad-spectrum antimicrobial activity using the paper disc agar diffusion method. This isolate showed a different antimicrobial profile than either ampicillin or nystatin and was found to produce at least eight antimicrobial components by bioautography. Suitable fermentation conditions for production of the active constituents were determined to be 28 day cultivation at 25 °C to 30 °C with a 10% inoculation ratio. Under these conditions, the SRB-22 was fermented, extracted and chemically investigated. So far an antimicrobial compound, mono-n-butyl phthalate, and an inactive compound, thymine, have been isolated and characterized.

  3. [Investigation of variation of the production of biological and chemical compounds of Hyssopus officinalis L].

    Science.gov (United States)

    Varga, E; Hajdú, Z; Veres, K; Máthé, I; Németh, E; Pluhár, Z; Bernáth, J

    1998-05-01

    Hyssopus officinalis L. (Lamiaceae family) has been cultivated in Central Europe for a long time. This essential oil containing species serves not only as spice but in many countries including Hungary, it is used as a folk medicine against certain respiratory diseases. Despite this fact, little is known about the variation of its productivity under Central European climatic conditions. The cultivated populations of hyssop can be characterised by a significant heterogenity. In the course of its breeding the uniformity of flower colour (e.g. blue form), and increase in the oil content are the main achievable purposes. The purpose of this work was to investigate both the variability of strains of different crigin and the time-dependent variations of its production parameters. The optimum of phytomass was obtained at the beginning of July. The essential oil content as well as compounds of the non volatile fractions were also investigated. The non volatile fractions for rosmarinic, caffeic acids were analysed mainly by TLC and densitometry. Both compounds were present in all samples and they are suitable for the characterisation of the plant. The essential oils were gained with Water Steam Distillation (WSD) and Supercritical Fluid Extraction (SFE) with CO2. The oils were analysed by GC, GC-MS techniques. In the essential oil composition of the populations studied significant heterogenity could be observed. In the case of applying SFE extraction the oil composition is more uniform, similarly to the obtained by WSD adding hexane. The heterogenity can be experienced in the offsprings, too. If only the main four components (beta-pinene, limonene, pinocamphone, isopinocamphone) are regarded, among the offsprings clear and mixed lines alike can be found. Results of these experiments justify the necessity and usefulness of selection which is going on. PMID:9703705

  4. Investigation of biological activity of polar extracts isolated from Phlomis crinita Cav ssp. mauritanica Munby.

    Science.gov (United States)

    Limem-Ben Amor, Ilef; Skandrani, Ines; Boubaker, Jihed; Ben Sghaïer, Mohamed; Neffati, Aicha; Bhouri, Wissem; Bouhlel, Ines; Chouchane, Nabil; Kilani, Soumaya; Guedon, Emmanuel; Ghoul, Mohamed; Ghedira, Kamel; Chekir-Ghedira, Leila

    2009-01-01

    The lyophilized infusion, the methanol, the ethyl acetate, and the total oligomer flavonoid (TOF)-enriched extracts prepared from the dried leaves of Phlomis crinita Cav. ssp. mauritanica Munby were investigated for the contents of flavonoids, tannins, coumarines and steroids. Antibacterial activity was investigated toward five bacterial strains. An inhibitory effect was observed against Staphyllococcus aureus and Enterococcus feacalis, and the minimal inhibitory concentrations ranged from 2.5 to 5 mg/mL of extract. The tested extracts exhibit an important free radical scavenging activity toward the 1,1-diphenyl 2-picrylhydrazyl (DPPH) free radical; with IC(50) values of 30.5, 6, 32, and 31.5 microg/mL, respectively, in the presence of lyophilized infusion, the TOF, the methanol, and the ethyl acetate extracts. Genotoxic and antigenotoxic properties of the different extracts were studied by using the SOS chromotest with Escherichia coli PQ37. The lyophilized infusion and TOF extracts obtained from P. crinita ssp. mauritanica showed no genotoxicity, whereas methanol and ethyl acetate extracts are considered as marginally genotoxic. On the other hand, we showed that each extract inhibited the mutagenicity induced by aflatoxin B1 (AFB1) (10 microg/assay) and nifuroxazide (NF) (10 microg/assay). The ethyl acetate extract showed the strongest level of protection toward the genotoxicity induced by both directly and indirectly genotoxic NF and AFB1. These tests proved that the lyophilized infusion possesses an antiradical activity likewise, it showed no genotoxic effect; that is why we choose this extract to assess its antiulcerogenic activity by using an ethanol-induced ulcerogenesis model in the rat. This test demonstrates that 300 mg/kg of a P. crinita ssp. mauritanica lyophilized infusion was more effective than the reference compound, cimetidine. PMID:19514937

  5. Investigation of the possible biological activities of a poisonous South African plant; Hyaenanche globosa (Euphorbiaceae

    Directory of Open Access Journals (Sweden)

    Saeideh Momtaz

    2010-01-01

    Full Text Available The present study was undertaken to explore the possible biochemical activities of Hyaenanche globosa Lamb. and its compounds. Two different extracts (ethanol and dichloromethane of four different parts (leaves, root, stem, and fruits of H. globosa were evaluated for their possible antibacterial, antityrosinase, and anticancer (cytotoxicity properties. Two pure compounds were isolated using column chromatographic techniques. Active extracts and pure compounds were investigated for their antioxidant effect on cultured ′Hela cells′. Antioxidant/oxidative properties of the ethanolic extract of the fruits of H. globosa and purified compounds were investigated using reactive oxygen species (ROS, ferric-reducing antioxidant power (FRAP, and lipid peroxidation thiobarbituric acid reactive substance (TBARS assays. The ethanolic extract of the leaves and fruits of H. globosa showed the best activity, exhibiting a minimum inhibitory concentration (MIC of 3.1 mg/ ml and a minimum bactericidal concentration (MBC of 1.56 and 6.2 mg/ml, respectively, against M. smegmatis. The ethanolic extract of the fruits of H. globosa (F.E showed the highest percentage of inhibitory activity of monophenolase (90.4% at 200 µg/ml. In addition, F.E exhibited 50% inhibitory concentration (IC 50 of 37.7 µg/ml on the viability of ′HeLa cells′ using cytotoxicity MTT assay. Subsequently, F.E was fractionated using phase-partitioning with n-hexane, ethyl acetate, and n-butanol. The cytotoxicity of these fractions were determined in vitro using different cancer cell lines. The n-hexane fraction exhibited the highest activity of toxicity. Therefore, this fraction was subjected to further separation by chromatographic methods. Two pure compounds known as: ′Tutin′ and ′hyenanchin′ were isolated and their structures were determined by NMR spectroscopic methods. Unpredictably, none of them showed significant ( P < 0.01 inhibition on cell viability/proliferation at the

  6. Investigating the biological impacts of nanoengineered materials in Caenorhabditis elegans and in vitro

    Science.gov (United States)

    Contreras, Elizabeth Quevedo

    In nematode Caenorhabditis elegans, the chronic and multi-generational toxicological effects of commercially relevant engineered nanoparticles (ENPs), such as quantum dots (QDs) and silver (AgNP) caused significant changes in a number of physiological endpoints. The increased water-solubility of ENPs in commercial products, for example, makes them increasingly bioavailable to terrestrial organisms exposed to pollution and waste in the soil. Since 2008, attention to the toxicology of nanomaterials in C. elegans continues to grow. Quantitative data on multiple physiological endpoints paired with metal analysis show the uptake of QDs and AgNPs, and their effects on nematode fitness. First, C. elegans were exposed for four generations through feeding to amphiphilic polymer coated CdSe/ZnS (core-shell QDs), CdSe (core QDs), and different sizes of AgNPs. These ENPs were readily ingested. QDs were qualitatively imaged in the digestive tract using a fluorescence microscopy and their and AgNP uptake quantitatively measured using ICP-MS. Each generation was analyzed for changes in lifespan, reproduction, growth and motility using an automated computer vision system. Core-shell QDs had little impact on C. elegans due to its metal shell coating. In contrast, core QDs lacked a metal shell coating, which caused significant changes to nematode physiology. iii In the same way, at high concentrations of 100 ppm, AgNP caused the most adverse effect to lifespan and reproduction related to particle size, but its adverse effect to motility had no correlation to particle size. Using C. elegans as an animal model allowed for a better understanding of the negative impacts of ENPs than with cytotoxicity tests. Lastly, to test the toxicity of water-dispersed fullerene (nanoC60) using human dermal fibroblast cells, this thesis investigated a suite of assays and methods in order to establish a standard set of cytotoxicity tests. Ten assays and methods assessed nanoC60 samples of different

  7. Structural study of magnesium phtalocyanin and tetraphenylporphyrin - polar molecule complexes

    International Nuclear Information System (INIS)

    As part of the structural study of biological magnesium compounds we examined the interaction of magnesium tetraphenyl porphyrin and phtalocyanin (TPPMg and PcMg) with nitrogenated polar molecules (pyridine and quinoline) as follows: - the infrared spectra of TPPMg and PcMg without external ligands were interpreted in the 4000 to 150 cm-1 region. By comparison with the IR spectra of TPPH2, PcH2, PcZn and PcFe II, and especially using the isotopic substitution 24Mg/26Mg; the absorption bands corresponding to the intramolecular magnesium-nitrogen vibrations were revealed. - the IR spectra of TPPMg, PcMg, PcFeII and PcZn complexes with pyridine and quinoline were interpreted next. The absorption bands of the intermolecular metal-nitrogen vibrations were identified. - these complexes were then studied quantitatively in the solid state by thermogravimetry: TPPMg pyridine was examined in benzene solution by absorption spectrometry in the visible and in carbon sulphide solution by infrared spectrometry. The equilibrium constants were determined for these systems at various temperatures and their thermodynamic constants (ΔH0 and ΔS0) of formation evaluated. From studies it was concluded that the stoichiometry of the complexes with pyridine (or quinoline) is 1:1 or 1:2 (one tetrapyrolic magnesium molecule for 1 or 2 pyridines); in the 1:1 complex the pyridine nitrogen interacts strongly and directly with the porphyrin magnesium (electron donor-acceptor system); the same applies to the second by weak interactions between the π systems of pyridine and of the tetrapyrolic ring, the tetrapyrolic molecule and pyridine planes probably being parallel. The model accounts for the fact that in these systems there is only one isosbestic point, whereas two are expected and observed for a 1:2 complex of the iron porphyrin-pyridine type. (author)

  8. Enigmatic Isovaline: Investigating the Stability, Racemization, and Formation of a Non-biological Meteoritic Amino Acid

    Science.gov (United States)

    Hudson, Reggie; Moore, Marla; Lewis, Ariel; Dworkin, Jason

    2008-01-01

    Among the Murchison meteoritic amino acids, isovaline stands out as being both nonbiological (non-protein) and having a relatively high abundance. While approximately equal amounts of D- and L-isovaline have been reported in Murchison and other CM meteorites, the molecule's structure appears to prohibit its racemization in aqueous solutions. We recently have investigated the low-temperature solid-phase chemistry of both isovaline and valine with an eye toward each molecule's formation, stability, and possible interconversions of D and L enantiomers. Ion-irradiated isovaline- and valinecontaining ices were examined by IR spectroscopy and highly-sensitive liquid chromatography/time-of-flight mass spectral methods to assess both amino acid destruction and racemization. Samples were studied in the presence and in the absence of water-ice, and the destruction of both isovaline and valine was measured as a function of radiation dose. In addition, we have undertaken experiments to synthesize isovaline, valine, and their amino acid isomers by solid-phase radiation-chemical pathways other than the oft-invoked Strecker process. This presentation will review and summarize some of our recent findings. -- Our work has been supported by a grant to the Goddard Center for Astrobiology through the NASA Astrobiology Institute. Experiments were performed in the Cosmic Ice Laboratory (RLH, MHM, AL) and the Astrobiology Analytical Laboratory (JPD, DPG) at the NASA Goddard Space Flight Center.

  9. Biological and radioecological investigations at the Ringhals nuclear power station, 1968-1987

    International Nuclear Information System (INIS)

    The summary is based on 19 papers, which are presented in the References. The reports concern fish, bottom-living animals, zooplankton and algae as well as the presence of radioactivity in the aquatic and terrestrial environments. The investigation has been conducted at the request of Vaesterbygden's Water Rights Court and present the experiences of twelve operational years, of which the last four years have been with the power station at full capacity. In judging the effects of the operation of the power station, particular emphasis has been placed on questions given priority by the Water Rights Court, namely fishing and radioactivity. As regards fishing, the direct effects of the cooling-system on fish in different developmental stages have been assessed to be of importance. Water-borne radioactivity has been traced in organisms and sediment in the area. The concentrations of different radionucleids originating from the power station are highest in algae and lowest in fish-meat. The results form the basis of calculations of the radioactive dose to man. (orig./HP)

  10. Lysozyme-magnesium aluminum silicate microparticles: Molecular interaction, bioactivity and release studies

    DEFF Research Database (Denmark)

    Kanjanakawinkul, Watchara; Medlicott, Natalie J.; Rades, Thomas;

    2015-01-01

    LSZ. Moreover, the LSZ extracted from microparticles prepared at pH 4 showed an obvious change in the tertiary structure, leading to a decrease in the biological activity of the LSZ released. These findings suggested that LSZ can strongly interact with MAS to form microparticles that may potentially......The objectives of this study were to investigate the adsorption behavior of lysozyme (LSZ) onto magnesium aluminum silicate (MAS) at various pHs and to characterize the LSZ–MAS microparticles obtained from the molecular interaction between LSZ and MAS. The results showed that LSZ could be bound...... onto the MAS layers at different pHs, leading to the formation of LSZ–MAS microparticles. The higher preparation pH permitted greater adsorption affinity but a lower adsorption capacity of LSZ onto MAS. LSZ could interact with MAS via hydrogen bonds and electrostatic forces, resulting in the formation...

  11. Biologic overview for the Nevada Nuclear Waste Storage Investigations, Nevada Test Site, Nye County, Nevada

    International Nuclear Information System (INIS)

    The Nevada Nuclear Waste Storage Investigations project study area includes five major vegetation associations characteristic of the transition between the northern extent of the Mojave Desert and the southern extent of the Great Basin Desert. A total of 32 species of reptiles, 66 species of birds, and 46 species of mammals are known to occur within these associations elsewhere on the Nevada Test Site. Ten species of plants, and the mule deer, wild horse, feral burro, and desert tortoise were defined as possible sensitive species because they are protected by federal and state regulations, or are being considered for such protection. The major agricultural resources of southern Nye County included 737,000 acres of public grazing land managed by the Bureau of Land Management, and 9500 acres of irrigated crop land located in the Beatty/Oasis valleys, the Amargosa Valley, and Ash Meadows. Range lands are of poor quality. Alfalfa and cotton are the major crops along with small amounts of grains, Sudan grass, turf, fruits, and melons. The largest impacts to known ecosystems are expected to result from: extensive disturbances associated with construction of roads, seismic lines, drilling pads, and surface facilities; storage and leaching of mined spoils; disposal of water; off-road vehicle travel; and, over several hundred years, elevated soil temperatures. Significant impacts to off-site areas such as Ash Meadows are anticipated if new residential developments are built there to accommodate an increased work force. Several species of concern and their essential habitats are located at Ash Meadows. Available literature contained sufficient baseline information to assess potential impacts of the proposed project on an area-wide basis. It was inadequate to support analysis of potential impacts on specific locations selected for site characterization studies, mining an exploratory shaft, or the siting and operation of a repository

  12. AM1/d parameters for Magnesium in Metalloenzymes. Journal of Chemical Theory and Computation

    Energy Technology Data Exchange (ETDEWEB)

    Imhof, Petra [University of Heidelberg; Noe, F [University of Heidelberg; Fischer, S. [University of Heidelberg; Smith, Jeremy C [ORNL

    2006-06-01

    AM1/d parameters are derived for magnesium, optimized for modeling reactions in metalloenzymes. The parameters are optimized with a Monte Carlo procedure so as to reproduce the geometries and energies of a training set calculated with density functional theory. The training set consists of compounds with magnesium coordinated to the oxygen atom of typical biological ligands. Optimization of AM1 parameters without extension to d functions leaves serious errors. The new AM1/d parameters provide a clear improvement in accuracy compared to the standard semiempirical methods AM1 and MNDO/d and will be particularly useful for modeling reactions in large biological systems at low computational cost.

  13. Bidentate RNA–magnesium clamps: On the origin of the special role of magnesium in RNA folding

    OpenAIRE

    Petrov, Anton S.; Bowman, Jessica C.; Harvey, Stephen C.; Williams, Loren Dean

    2011-01-01

    Magnesium plays a special role in RNA function and folding. Although water is magnesium's most common first-shell ligand, the oxyanions of RNA have significant affinity for magnesium. Here we provide a quantum mechanical description of first-shell RNA–magnesium and DNA–magnesium interactions, demonstrating the unique features that characterize the energetics and geometry of magnesium complexes within large folded RNAs. Our work focuses on bidentate chelation of magnesium by RNA or DNA, where ...

  14. Correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys

    OpenAIRE

    Feliu Jr., S.; Pardo, Angel; Merino, M. C.; Coy, A. E.; Viejo, F.; Arrabal, R.

    2009-01-01

    X-ray photoelectron spectroscopy (XPS) was used in order to investigate the correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys exposed to 98% relative humidity at 50 °C. Commercially pure magnesium, used as the reference material, revealed MgO, Mg(OH)2 and tracers of magnesium carbonate in the air-formed film. For the AZ80 and AZ91D alloys, the amount of magnesium carbonate formed on the surface reached similar values to those of M...

  15. Novel antineoplastic platinum(IV) complexes: synthesis, characterization, biological investigations and structure-activity relationships

    International Nuclear Information System (INIS)

    the new complexes was conducted in order to better understand their pharmacological behavior. Finally, computational studies with respect to the electronic structure and redox properties of the investigated compounds, using DFT methods were performed. Furthermore, QSAR models with good explanatory and predictive properties for the cytotoxicity in the cisplatin sensitive cell line CH1 and the intrinsically cisplatin resistant cell line SW480 were developed. (author)

  16. Synthesis, Characterization and Functionalization of Polymeric Nanoparticles and Investigation of the Interaction with Biological Systems

    International Nuclear Information System (INIS)

    One of the main goals of nanomedicine is to improve the treatment of hazardous diseases whose conventional therapy often has serious side effects. The vision is to create a theranostic drug delivery system which is capable of safely transporting therapeutic cargo through the body to a targeted site of disease at which point the drug is released. Furthermore, it is desirable to track the carrier in real time which would allow for a personal adjustment of the therapy. Studies on the behavior of nanoparticulate substances in a physiological environment form the basis for the possibility to successfully develop a drug carrier system. In the present work, polymeric nanoparticles with different morphologies were prepared by the controlled self-assembly of amphiphilic block copolymers. The nanoparticles were subsequently characterized and their interactions with human cells and serum proteins investigated. A cytotoxicity study with spherical and cylindrical micelles as well as vesicular structures was carried out and showed a dependency of cytotoxic effects on the geometry and size of the nanoparticles. The agglomeration behavior of various polymeric nanoparticles in the presence of serum proteins was also studied. Highly uniform polymeric vesicles were continuously manufactured in a micromixer based device and in situ loading with different components was performed. In this way, dual loaded vesicles with the anticancer drug camptothecin and a high amount of hydrophobic iron oxide nanoparticles were produced. When tested in vitro, these drug-loaded vesicles showed an increased cytotoxic activity against the cancer cell line PC-3 when compared to the free drug. Specific cellular uptake in PC-3 cancer cells was demonstrated with flow cytometry and confocal laser scanning microscopy after functionalization with a cancer cell specific targeting peptide and an additional fluorescent label. Magnetic characterization of the iron oxide-loaded vesicles also confirmed the potential

  17. Fiscal 1995 investigation on biological fixation of carbon dioxide; 1995 nendo seibutsuteki CO2 kotei ni kansuru chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    To cope with the global warming caused by CO2, an investigation was conducted into biological fixation. It is necessary to make a many-sided and comprehensive study on the mechanism of CO2 fixation, the scale (area and carbon holding density), the rate and the environmental impact of the introduction of the technology and the technical problems, and to make a quantitative evaluation of each of the methods in order to make them practical proposals. The global ecosystem is classified into the land biota and ocean biota, and each typical ecosystem was surveyed in terms of the surface area, the carbon holding amount (presently existing amount), the net primary production amount, the required nutrient salt amount, the transpiration rate, etc. Next, a discussion was made on the increasing effect of the carbon fixation amount by changing the present ecosystem from the aspect of scale and rate. At the same time, a study was carried out of energy efficiency, economical efficiency and problems. Last, elementary technology was taken up which seems to be important for implementing measures for the biological carbon fixation. As to the ocean, it is necessary to obtain information, which is not sufficient to utilize marine biota for CO2 fixation, especially on the mechanism of depth-direction transfer of organism and its quantitative grasp. As to the land, one of the measures is conversion of the ecosystem where the amount of carbon fixed is small to the ecosystem where the amount is large. 249 refs., 58 figs., 51 tabs.

  18. Toward increased concentration sensitivity for continuous wave EPR investigations of spin-labeled biological macromolecules at high fields

    Science.gov (United States)

    Song, Likai; Liu, Zhanglong; Kaur, Pavanjeet; Esquiaqui, Jackie M.; Hunter, Robert I.; Hill, Stephen; Smith, Graham M.; Fanucci, Gail E.

    2016-04-01

    High-field, high-frequency electron paramagnetic resonance (EPR) spectroscopy at W-(∼94 GHz) and D-band (∼140 GHz) is important for investigating the conformational dynamics of flexible biological macromolecules because this frequency range has increased spectral sensitivity to nitroxide motion over the 100 ps to 2 ns regime. However, low concentration sensitivity remains a roadblock for studying aqueous samples at high magnetic fields. Here, we examine the sensitivity of a non-resonant thin-layer cylindrical sample holder, coupled to a quasi-optical induction-mode W-band EPR spectrometer (HiPER), for continuous wave (CW) EPR analyses of: (i) the aqueous nitroxide standard, TEMPO; (ii) the unstructured to α-helical transition of a model IDP protein; and (iii) the base-stacking transition in a kink-turn motif of a large 232 nt RNA. For sample volumes of ∼50 μL, concentration sensitivities of 2-20 μM were achieved, representing a ∼10-fold enhancement compared to a cylindrical TE011 resonator on a commercial Bruker W-band spectrometer. These results therefore highlight the sensitivity of the thin-layer sample holders employed in HiPER for spin-labeling studies of biological macromolecules at high fields, where applications can extend to other systems that are facilitated by the modest sample volumes and ease of sample loading and geometry.

  19. In Vitro Corrosion and Cytocompatibility of ZK60 Magnesium Alloy Coated with Hydroxyapatite by a Simple Chemical Conversion Process for Orthopedic Applications

    Directory of Open Access Journals (Sweden)

    Bing Wang

    2013-12-01

    Full Text Available Magnesium and its alloys—a new class of degradable metallic biomaterials—are being increasingly investigated as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. However, the high corrosion rate in physiological environments prevents the clinical application of Mg-based materials. Therefore, the objective of this study was to develop a hydroxyapatite (HA coating on ZK60 magnesium alloy substrates to mediate the rapid degradation of Mg while improving its cytocompatibility for orthopedic applications. A simple chemical conversion process was applied to prepare HA coating on ZK60 magnesium alloy. Surface morphology, elemental compositions, and crystal structures were characterized using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, respectively. The corrosion properties of samples were investigated by immersion test and electrochemical test. Murine fibroblast L-929 cells were harvested and cultured with coated and non-coated ZK60 samples to determine cytocompatibility. The degradation results suggested that the HA coatings decreased the degradation of ZK60 alloy. No significant deterioration in compression strength was observed for all the uncoated and coated samples after 2 and 4 weeks’ immersion in simulated body fluid (SBF. Cytotoxicity test indicated that the coatings, especially HA coating, improved cytocompatibility of ZK60 alloy for L929 cells.

  20. The influence of heat treatment on the microstructure of GA8 magnesium alloy

    Directory of Open Access Journals (Sweden)

    A. Kiełbus

    2007-01-01

    Full Text Available Purpose: GA8 magnesium alloy is a general purpose gravity sand casting alloy containing aluminum, zincand manganese. Typically, it is used in aerospace or commercial casting applications particularly where thereis no high temperature requirement. The aim of this paper is to present the results of investigations on themicrostructure of the GA8 magnesium alloy after heat treatment.Design/methodology/approach: The study was conducted on GA8 magnesium alloys in as-cast conditionand after heat treatment. The microstructure was characterized by optical microscopy (Olympus GX-70 and ascanning electron microscopy (Hitachi S3400 equipped with an electron dispersive detector EDS (VOYAGERof NORAN INSTRUMENTS. To measure the stereological parameters, an image analysis program“AnalysisPro®” was used.Findings: The microstructure of GA8 magnesium alloy has a solid solution structure α with α + d iscontinuous ßareas and continuous ß (Mg17Al12 phase at grain boundaries. After solution treatment a reduction of the number ofß precipitations was observed. Application of ageing treatment caused precipitation of discontinuous ß phase.Research limitations/implications: Future researches should involve investigations of the effect of heattreatment parameters on the mechanical properties of GA8 magnesium alloy.Practical implications: The established heat treatment parameters can be useful for preparing heat treatmenttechnology of the GA8 magnesium alloy.Originality/value: The relationship between the initial structure, heat treatment parameters and Mg17Al12 phasemorphology in GA8 magnesium alloy was specified.

  1. Magnesium deficiency and cardiovascular diseases: time to act

    OpenAIRE

    E. I. Trisvetova

    2014-01-01

    Progression of cardiovascular disease is often caused by a deficiency of magnesium in the human body. Magnesium belongs to the necessary vital macronutrients providing many physiological and pathological reactions and is involved in the constructive, energy, electrolyte metabolism. Correction of magnesium deficiency is realized using magnesium-containing drugs, for example magnesium orotate, having pleiotropic effects due to independent metabolic activity of orotic acid.

  2. The dynamics of the biological membrane surrounding the buffalo milk fat globule investigated as a function of temperature.

    Science.gov (United States)

    Nguyen, Hanh T H; Madec, Marie-Noëlle; Ong, Lydia; Kentish, Sandra E; Gras, Sally L; Lopez, Christelle

    2016-08-01

    The biological membrane surrounding fat globules in milk (the MFGM) is poorly understood, despite its importance in digestion and in determining the properties of fat globules. In this study, in situ structural investigations of buffalo MFGM were performed as a function of temperature (4-60°C), using confocal microscopy. We demonstrate that temperature and rate of temperature change affected the lipid domains formed in the MFGM with the lateral segregation (i) of high Tm lipids and cholesterol in a Lo phase for both TTm and (ii) of high Tm lipids in a gel phase for T

  3. [Our investigation on the chemistry of biologically active natural products. With the object of exploitation for structure determination methods, and elucidation of vital function].

    Science.gov (United States)

    Komori, T

    1993-03-01

    Our investigation on the chemistry of biologically active natural products during the last 40 years since 1953 are reviewed in this paper. The following subjects are discussed: I. photochemical relationship between rhodopsin and compounds related to areca alkaloid, II. furanoid diterpenoid constituents from dioscoreaceae plants and colombo root, III. field desorption and fast atom bombardment mass spectrometry of biologically active natural glycosides and glycosphingolipids, IV. investigation of biologically active marine natural products, 1) constituents of steroid glycoside sulfates from Asteroidea, 2) spine toxins from Acanthaster planci, 3) constituents of triterpenoid glycoside sulfates from Holothuroidea, 4) constituents of isoprenoids from Opisthobranchia and Octocorallia, 5) constituents of glycosphingolipids from Asteroidea. PMID:8509990

  4. The initial stage of surface modification of magnesium alloys by high intensity pulse ions beam

    Science.gov (United States)

    Li, P.; Liu, Z. H.; Zhang, Z. P.

    2016-06-01

    The initial stage of high intensity pulsed ion beam irradiated magnesium alloys was studied by MD simulation. Specimens containing Mg17Al12 precipitation were modeled to investigate the evolution of magnesium alloys during several picoseconds after a high-energy ion impacting. It was found that the Mg17Al12 precipitation has little effects on the kinetic energy evolution in the heat zone, but considerable effects on strength of kinetic energy peak moving to the deep matrix and on the surface morphology of the magnesium alloy at thermal equilibrium state. The thickness of the heat zone is independent on the temperature of surface region.

  5. Nafion/polypyrrole and Nafion/DMSO Organic Coatings for Magnesium Protection

    Institute of Scientific and Technical Information of China (English)

    Renguo SONG; Xiaohua ZHENG; Carsten Blawert; Wolfgang Dietzel

    2007-01-01

    Nafion/polypyrrole and Nafion/Dimethysulfoxid (DMSO) organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic coatings were investigated by using optical microscopy and electrochemical corrosion testing, respectively. It is shown that Nafion/polypyrrole organic coatings resulted in the corrosion resistance of magnesium decreasing;while Nafion/DMSO organic coatings can effectively improve the corrosion resistance of magnesium. Also,the corrosion resistance increased with the thickness of the Nafion/DMSO organic coating increased.

  6. Effect of neodymium on the as-extruded ZK20 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    赵亚忠; 潘复生; 彭建; 王维青; 罗素琴

    2010-01-01

    The effect of Nd addition on the microstructure and mechanical properties of ZK20 magnesium alloy was investigated by room tensile test, optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) in order to develop a magnesium alloy with higher ductility. Results showed that the crystal grains of as-extruded ZK20+0.5%Nd magnesium alloy were effectively refined, and the alloy exhibited higher strength and ductility, with the UTS of 237 MPa and the elongation of 32.8%, increasing by 5...

  7. Calcium and magnesium silicate hydrates

    International Nuclear Information System (INIS)

    Deep geological disposals are planed to discard long-lived intermediate-level and high-level radioactive wastes. Clay-based geological barriers are expected to limit the ingress of groundwater and to reduce the mobility of radioelements. In the interaction zone between the cement and the clay based material alteration can occur. Magnesium silicate hydrates (M-S-H) have been observed due to the reaction of magnesium sulfate containing groundwater with cements or in the interaction zone between low-pH type cement and clays. M-S-H samples synthesized in the laboratory showed that M-S-H has a variable composition within 0.7 ≤ Mg/Si ≤ 1.5. TEM/EDS analyses show an homogeneous gel with no defined structure. IR and 29Si NMR data reveal a higher polymerization degree of the silica network in M-S-H compared to calcium silicate hydrates (C-S-H). The presence of mainly Q3 silicate tetrahedrons in M-S-H indicates a sheet like or a triple-chain silica structure while C-S-H is characterised by single chain-structure. The clear difference in the silica structure and the larger ionic radius of Ca2+ (1.1 Angstrom) compared to Mg2+ (0.8 Angstrom) make the formation of an extended solid solution between M-S-H and C-S-H gel improbable. In fact, the analyses of synthetic samples containing both magnesium and calcium in various ratios indicate the formation of separate M-S-H and C-S-H gels with no or very little uptake of magnesium in CS-H or calcium in M-S-H

  8. Research on the preparation, biocompatibility and bioactivity of magnesium matrix hydroxyapatite composite material.

    Science.gov (United States)

    Linsheng, Li; Guoxiang, Lin; Lihui, Li

    2016-08-12

    In this paper, magnesium matrix hydroxyapatite composite material was prepared by electrophoretic deposition method. The optimal process parameters of electrophoretic deposition were HA suspension concentration of 0.02 kg/L, aging time of 10 days and voltage of 60 V. Animal experiment and SBF immersion experiment were used to test the biocompatibility and bioactivity of this material respectively. The SD rats were divided into control group and implant group. The implant surrounding tissue was taken to do tissue biopsy, HE dyed and organizational analysis after a certain amount of time in the SD rat body. The biological composite material was soaked in SBF solution under homeothermic condition. After 40 days, the bioactivity of the biological composite material was evaluated by testing the growth ability of apatite on composite material. The experiment results showed that magnesium matrix hydroxyapatite biological composite material was successfully prepared by electrophoretic deposition method. Tissue hyperplasia, connective tissue and new blood vessels appeared in the implant surrounding soft tissue. No infiltration of inflammatory cells of lymphocytes and megakaryocytes around the implant was found. After soaked in SBF solution, a layer bone-like apatite was found on the surface of magnesium matrix hydroxyapatite biological composite material. The magnesium matrix hydroxyapatite biological composite material could promot calcium deposition and induce bone-like apatite formation with no cytotoxicity and good biocompatibility and bioactivity. PMID:27567779

  9. Substrate and method for the formation of continuous magnesium diboride and doped magnesium diboride wire

    Science.gov (United States)

    Suplinskas, Raymond J.; Finnemore, Douglas; Bud'ko, Serquei; Canfield, Paul

    2007-11-13

    A chemically doped boron coating is applied by chemical vapor deposition to a silicon carbide fiber and the coated fiber then is exposed to magnesium vapor to convert the doped boron to doped magnesium diboride and a resultant superconductor.

  10. Selective Aerobic Oxidation of 5-Hydroxymethylfurfural in Water Over Solid Ruthenium Hydroxide Catalysts with Magnesium-Based Supports

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Riisager, Anders

    2011-01-01

    Solid catalyst systems comprised of ruthenium hydroxide supported on magnesium-based carrier materials (spinel, magnesium oxide and hydrotalcite) were investigated for the selective, aqueous aerobic oxidation of the biomass-derived chemical 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid...

  11. 76 FR 62040 - Pure Magnesium From the People's Republic of China: Final Results of Expedited Third Sunset...

    Science.gov (United States)

    2011-10-06

    ... Value: Antidumping Duty Investigation of Pure Magnesium From the Russian Federation, 60 FR 25691 (May 12..., pursuant to section 751(c) of the Act. See Initiation of Five-Year ``Sunset'' Review, 76 FR 31588 (June 1... International Trade Administration Pure Magnesium From the People's Republic of China: Final Results...

  12. 77 FR 33165 - Pure Magnesium in Granular Form From the People's Republic of China: Final Results of Expedited...

    Science.gov (United States)

    2012-06-05

    ... Value: Antidumping Duty Investigation of Pure Magnesium From the Russian Federation, 60 FR 25691 (May 12... pure magnesium in granular form. See Notice of Scope Rulings and Anticircumvention Inquiries, 68 FR... expedited review of this order. \\1\\ See Initiation of Five-Year (``Sunset'') Review, 77 FR 4995 (February...

  13. 77 FR 63787 - Pure Magnesium in Granular Form from the People's Republic of China: Continuation of Antidumping...

    Science.gov (United States)

    2012-10-17

    ... Value: Antidumping Duty Investigation of Pure Magnesium From the Russian Federation, 60 FR 25691 (May 12... pure magnesium in granular form. See Notice of Scope Rulings and Anticircumvention Inquiries, 68 FR... (``the Act'').\\1\\ \\1\\ See Initiation of Five-Year (``Sunset'') Review, 77 FR 4995 (February 1,...

  14. 75 FR 51002 - Pure Magnesium In Granular Form from the People's Republic of China: Initiation of Changed...

    Science.gov (United States)

    2010-08-18

    ...: Pure Magnesium in Granular Form From the People's Republic of China, 66 FR 57936 (November 19, 2001... Investigation of Pure Magnesium From the Russian Federation, 60 FR 25691 (May 12, 1995). The scope of this order... of Initiation of Changed Circumstances Review, 74 FR 19934 (April 30, 2009). \\7\\ See, e.g., Notice...

  15. 75 FR 20817 - Magnesium Metal from the People's Republic of China: Preliminary Results of the 2008-2009...

    Science.gov (United States)

    2010-04-21

    ... Duty Investigation of Pure Magnesium from the Russian Federation, 60 FR 25691 (May 12, 1995). \\2\\ See... Federation, 60 FR 25691 (May 12, 1995); and Antidumping Duty Order: Pure Magnesium in Granular Form from the People's Republic of China, 66 FR 57936 (Nov. 19, 2001). \\12\\ This third exclusion for...

  16. Lightweight Heat Pipes Made from Magnesium

    Science.gov (United States)

    Rosenfeld, John N.; Zarembo, Sergei N.; Eastman, G. Yale

    2010-01-01

    Magnesium has shown promise as a lighter-weight alternative to the aluminum alloys now used to make the main structural components of axially grooved heat pipes that contain ammonia as the working fluid. Magnesium heat-pipe structures can be fabricated by conventional processes that include extrusion, machining, welding, and bending. The thermal performances of magnesium heat pipes are the same as those of equal-sized aluminum heat pipes. However, by virtue of the lower mass density of magnesium, the magnesium heat pipes weigh 35 percent less. Conceived for use aboard spacecraft, magnesium heat pipes could also be attractive as heat-transfer devices in terrestrial applications in which minimization of weight is sought: examples include radio-communication equipment and laptop computers.

  17. Crystallization of Esomeprazole Magnesium Water/Butanol Solvate.

    Science.gov (United States)

    Skieneh, Jenna; Khalili Najafabadi, Bahareh; Horne, Stephen; Rohani, Sohrab

    2016-01-01

    The molecular structure of esomeprazole magnesium derivative in the solid-state is reported for the first time, along with a simplified crystallization pathway. The structure was determined using the single crystal X-ray diffraction technique to reveal the bonding relationships between esomeprazole heteroatoms and magnesium. The esomeprazole crystallization process was carried out in 1-butanol and water was utilized as anti-solvent. The product proved to be esomeprazole magnesium tetrahydrate with two 1-butanol molecules that crystallized in P6₃ space group, in a hexagonal unit cell. Complete characterization of a sample after drying was conducted by the use of powder X-ray diffraction (PXRD), ¹H-nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), infrared spectroscopy (IR), and dynamic vapor sorption (DVS). Investigation by ¹H-NMR and TGA has shown that the solvent content in the dried sample consists of two water molecules and 0.3 butanol molecules per esomeprazole magnesium molecule. This is different from the single crystal X-ray diffraction results and can be attributed to the loss of some water and 1-butanol molecules stabilized by intermolecular interactions. The title compound, after drying, is a true solvate in terms of water; conversely, 1-butanol fills the voids of the crystal lattice in non-stoichiometric amounts. PMID:27120591

  18. Crystallization of Esomeprazole Magnesium Water/Butanol Solvate

    Directory of Open Access Journals (Sweden)

    Jenna Skieneh

    2016-04-01

    Full Text Available The molecular structure of esomeprazole magnesium derivative in the solid-state is reported for the first time, along with a simplified crystallization pathway. The structure was determined using the single crystal X-ray diffraction technique to reveal the bonding relationships between esomeprazole heteroatoms and magnesium. The esomeprazole crystallization process was carried out in 1-butanol and water was utilized as anti-solvent. The product proved to be esomeprazole magnesium tetrahydrate with two 1-butanol molecules that crystallized in P63 space group, in a hexagonal unit cell. Complete characterization of a sample after drying was conducted by the use of powder X-ray diffraction (PXRD, 1H-nuclear magnetic resonance (NMR, thermogravimetric analysis (TGA, differential scanning calorimetry (DSC, infrared spectroscopy (IR, and dynamic vapor sorption (DVS. Investigation by 1H-NMR and TGA has shown that the solvent content in the dried sample consists of two water molecules and 0.3 butanol molecules per esomeprazole magnesium molecule. This is different from the single crystal X-ray diffraction results and can be attributed to the loss of some water and 1-butanol molecules stabilized by intermolecular interactions. The title compound, after drying, is a true solvate in terms of water; conversely, 1-butanol fills the voids of the crystal lattice in non-stoichiometric amounts.

  19. THE ROLE OF MAGNESIUM METABOLISM IN ESSENTIALHYPERTENSION WITH INSULIN RESISTANCE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective To investigate the effects of magnesium metabolism and other positive ions in pathogenesis of essential hypertension(EH) patients with insulin resistance(IR). Methods The levels of Na+, K+, Ca2+, Mg2+ in erythrocyte and 24-hour urine samples were observed in 47 EH patients and in 30 subjects with normal blood pres sure. Insulin sensitivity index was used to evaluate the insulin sensitivity. Results In EH patients, the levels of K+ and Mg2+ in erythrocyte declined, but the levels of Na+ and Ca2+ in erythrocyte increased, and the 24-hour urinary excretion of Mg2+ reduced as compared to the subjects with normal blood pressure (P <0. 05). The levels of K+ and Mg2+ in erythrocyte of EH patients positively correlated with insulin sensitivity index, and the Mg2+ level in erythro cyte positively correlated with 24-hour urinary excretion of Ca2+ and Mg2+ , and the K+ level in erythrocyte. Conclu sion Abnormality of magnesium metabolism in EH patients may be the linking factor for hypertension and insulin re sistance, and may relate to inadequate intake of magnesium. Calcium and potassium may be involved in the occur rence of insulin resistance through affecting magnesium metabolism.

  20. Role of Cellular Magnesium in Human Diseases

    OpenAIRE

    Long, Samantha; Romani, Andrea MP

    2014-01-01

    Magnesium is required for many of the major organs to function and plays a crucial role in human and mammalian physiology. Magnesium is essential for the structure of bones and teeth, acts as a cofactor for more than 300 enzymes in the body, including binding to ATP for kinase reactions, and affects permeability of excitable membranes and neuromuscular transmission. Despite these essential roles, much is still unknown about magnesium physiology and homeostasis. Currently, nutritionists believ...

  1. Inhibition of self-corrosion in magnesium by poisoning hydrogen recombination on iron impurities

    International Nuclear Information System (INIS)

    Highlights: ► Arsenate evaluated as a corrosion inhibitor on magnesium. ► Magnesium corrosion followed by measuring evolved hydrogen. ► Arsenate found to profoundly inhibit magnesium corrosion at pH 2. ► Arsenate proposed to act by poisoning hydrogen atom recombination. ► Cathodic sites poisoned by arsenic are iron-rich second phase particles. - Abstract: A volumetric measurement of evolved hydrogen is used to quantify rates of corrosion occurring on unpolarized samples of commercially “pure” magnesium immersed in 5% (w/v) aqueous sodium chloride electrolyte. This approach is used to compare rates of uninhibited corrosion with rates occurring in the presence of arsenate and phosphate corrosion inhibitor species dissolved in the experimental electrolyte at concentrations between 10−4 and 10−2 mol dm−3. The effective cathode in commercially pure magnesium comprises a population of micron and submicron size iron-rich particles widely dispersed in the magnesium matrix. It is shown that arsenate, but not phosphate, acts to poison the hydrogen atom recombination reaction as it occurs on the surface of these cathodic particles. It is shown that because hydrogen evolution is the predominant cathodic process the onset of H-atom recombination poisoning results in greatly reduced rates of magnesium corrosion. Additional mechanistic information regarding the effect of phosphate and arsenate corrosion inhibitors is obtained through systematically investigating the effect of solution pH on inhibitor efficiency.

  2. The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Y.S., E-mail: yshzou75@gmail.com [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094 (China); Wu, Y.F.; Yang, H.; Cang, K. [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094 (China); Song, G.H. [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang, Liaoning, 110178 (China); Li, Z.X.; Zhou, K. [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094 (China)

    2011-12-01

    Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to -200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp{sup 3} carbon content and mechanical properties of the deposited DLC films. A maximum sp{sup 3} content of 33.3% was obtained at -100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.

  3. The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

    International Nuclear Information System (INIS)

    Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to -200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp3 carbon content and mechanical properties of the deposited DLC films. A maximum sp3 content of 33.3% was obtained at -100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.

  4. The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

    Science.gov (United States)

    Zou, Y. S.; Wu, Y. F.; Yang, H.; Cang, K.; Song, G. H.; Li, Z. X.; Zhou, K.

    2011-12-01

    Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to -200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp3 carbon content and mechanical properties of the deposited DLC films. A maximum sp3 content of 33.3% was obtained at -100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.

  5. Corrosion resistance of Elektron 21 magnesium alloy

    Directory of Open Access Journals (Sweden)

    A. Kiełbus

    2007-05-01

    Full Text Available Purpose: Elektron 21 magnesium alloy containing neodymium, gadolinium and zinc has high strength, good corrosion resistance and excellent castability. It is designed mainly for aerospace applications. The purpose of the investigation was to study the corrosion resistance of Elektron 21 magnesium alloy in as cast condition and after heat treatment in 3.5% NaCl saturated with Mg(OH2 solution.Design/methodology/approach: Solution treatment was performed at 525°C/8h/water, while ageing treatments at following conditions 250°C/4-96h/air. Immersion test was performed in 3.5% NaCl saturated with Mg(OH2 solution at room temperature. Specimens were placed in 3.5% NaCl solution for periods of time between one and 5 days. After immersion test, the microstructure and the appearances of the corroded structure were examined by optical microscopy (Olympus GX-70 and a scanning electron microscopy (Hitachi S3400.Findings: The corrosion rates of Elektron 21 alloy increased with increasing the exposure time and finally (after 5 days reached maximum value 0.092 mg/cm-2day-1. Solution treatment at 520°C for 8 h caused decrease in corrosion rate (0.072 mg cm-2 day-1 due to dissolving of intermetallic phase precipitates at matrix. Ageing at 200°C for 4h and 16h caused next decrease in corrosion rate to value 0.052 and 0,055 mg cm-2 day-1 respectively, while after ageing for 48h corrosion rate increase to value 0.067 mg cm-2 day-1, due to increase of volume fraction and size of β’ phase and precipitations of equilibrium β phase. It was also noticed that the longer time of ageing the higher corrosion rates were observed.Research limitations/implications: Future researches should include investigations of the influence of other environments on the corrosion resistance of Elektron 21 alloy.Practical implications: The improvement of corrosion resistance of Elektron 21 alloy can cause increase in it application in aerospace industry.Originality/value: The

  6. An open source based high content screening method for cell biology laboratories investigating cell spreading and adhesion.

    Directory of Open Access Journals (Sweden)

    Andre Schmandke

    Full Text Available BACKGROUND: Adhesion dependent mechanisms are increasingly recognized to be important for a wide range of biological processes, diseases and therapeutics. This has led to a rising demand of pharmaceutical modulators. However, most currently available adhesion assays are time consuming and/or lack sensitivity and reproducibility or depend on specialized and expensive equipment often only available at screening facilities. Thus, rapid and economical high-content screening approaches are urgently needed. RESULTS: We established a fully open source high-content screening method for identifying modulators of adhesion. We successfully used this method to detect small molecules that are able to influence cell adhesion and cell spreading of Swiss-3T3 fibroblasts in general and/or specifically counteract Nogo-A-Δ20-induced inhibition of adhesion and cell spreading. The tricyclic anti-depressant clomipramine hydrochloride was shown to not only inhibit Nogo-A-Δ20-induced cell spreading inhibition in 3T3 fibroblasts but also to promote growth and counteract neurite outgrowth inhibition in highly purified primary neurons isolated from rat cerebellum. CONCLUSIONS: We have developed and validated a high content screening approach that can be used in any ordinarily equipped cell biology laboratory employing exclusively freely available open-source software in order to find novel modulators of adhesion and cell spreading. The versatility and adjustability of the whole screening method will enable not only centers specialized in high-throughput screens but most importantly also labs not routinely employing screens in their daily work routine to investigate the effects of a wide range of different compounds or siRNAs on adhesion and adhesion-modulating molecules.

  7. Nanocomposite polymer electrolyte for rechargeable magnesium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Yuyan; Rajput, Nav Nidhi; Hu, Jian Z.; Hu, Mary Y.; Liu, Tianbiao L.; Wei, Zhehao; Gu, Meng; Deng, Xuchu; Xu, Suochang; Han, Kee Sung; Wang, Jiulin; Nie, Zimin; Li, Guosheng; Zavadil, K.; Xiao, Jie; Wang, Chong M.; Henderson, Wesley A.; Zhang, Jiguang; Wang, Yong; Mueller, Karl T.; Persson, Kristin A.; Liu, Jun

    2015-03-01

    Nanocomposite polymer electrolytes present new opportunities for rechargeable magnesium batteries. However, few polymer electrolytes have demonstrated reversible Mg deposition/dissolution and those that have still contain volatile liquids such as tetrahydrofuran (THF). In this work, we report a nanocomposite polymer electrolyte based on poly(ethylene oxide) (PEO), Mg(BH4)2 and MgO nanoparticles for rechargeable Mg batteries. Cells with this electrolyte have a high coulombic efficiency of 98% for Mg plating/stripping and a high cycling stability. Through combined experiment-modeling investigations, a correlation between improved solvation of the salt and solvent chain length, chelation and oxygen denticity is established. Following the same trend, the nanocomposite polymer electrolyte is inferred to enhance the dissociation of the salt Mg(BH4)2 and thus improve the electrochemical performance. The insights and design metrics thus obtained may be used in nanocomposite electrolytes for other multivalent systems.

  8. Corrosion Protection of AM50 Magnesium Alloy by Nafion/DMSO Organic Coatings

    Institute of Scientific and Technical Information of China (English)

    SONG Renguo; ZHENG Xiaohua; BAI Shuju; BLAWERT Carsten; DIETZEL Wolfgang

    2008-01-01

    The effectiveness of the corrosion protection of Nafion/Dimethysulfoxid (DMSO) organic coatings for AM50 magnesium alloy prepared by simple immersion and heat treatment was investigated. Its corrosion resistance and morphologies of the Nafion/DMSO organic coatings were studied by electrochemical corrosion testing and optical microscopy. The results show that Nafion/DMSO organic coatings can improve the corrosion resistance of AM50 magnesium alloy effectively. Also, the corrosion resistance increases with the surface density of the organic coatings.

  9. CO2 laser beam welding of AM60 magnesium-based alloy

    OpenAIRE

    BELHADJ, Asma; MASSE, Jean-Eric; Barrallier, Laurent; BOUHAFS, Mahmoud; BESSROUR, Jamel

    2010-01-01

    Magnesium alloys have a 33% lower density than aluminum alloys, whereas they exhibit the same mechanical characteristics. Their application increases in many economic sectors, in particular, in aeronautic and automotive industries. Nevertheless, their assembly with welding techniques still remains to be developed. In this paper, we present a CO2 laser welding investigation of AM60 magnesium-based alloy. Welding parameters range is determinate for the joining of 3 mm thickness sheets. The effe...

  10. Localized approach to galvanic coupling in an aluminum–magnesium system

    OpenAIRE

    Lacroix, Loïc; Blanc, Christine; Pébère, Nadine; Tribollet, Bernard; Vivier, Vincent

    2009-01-01

    The corrosion behavior of a pure aluminum/pure magnesium couple in a weakly conductive sodium sulfate solution was investigated. Potential and current distributions on the surface of the model couple at the beginning of immersion were obtained by solving the Laplace equation using a finite element method algorithm. Magnesium acted as the anode of the system while oxygen and water were reduced on aluminum. Calculations predicted a large current peak at the Al/Mg interface related to a local in...

  11. Use of Propranolol-Magnesium Aluminium Silicate Intercalated Complexes as Drug Reservoirs in Polymeric Matrix Tablets

    OpenAIRE

    T. Pongjanyakul; S Rojtanatanya

    2012-01-01

    The objective of the present study was to investigate the use of propranolol-magnesium aluminium silicate intercalated complexes as drug reservoirs in hydroxypropylmethylcellulose tablets. The matrix tablets containing the complexes were prepared and characterised with respect to propranolol release and were subsequently compared with those loading propranolol or a propranolol-magnesium aluminium silicate physical mixture. Additionally, the effects of varying viscosity grades of hydroxypropyl...

  12. Study on Semi-solid Rheocasting Forming for Magnesium Alloy by Mechanical Stirring

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper the effect of pouring temperature of magnesium melt, preheating temperature of the barrel of screw mixer and shear rate on the solidified microstructures of semi-solid slurry was investigated by mechanical stirring method. The appropriate processing parameters of slurry preparation were obtained. The mold filling for thin walled casting was examined. Results indicated that the solid volume fraction of non-dendritic structure increased with decrease in pouring temperature of magnesium melt and ...

  13. Respon Morfologi dan Fisiologi Pada Kelapa Sawit (Elaeis guineensis Jacq.) Terhadap Aplikasi Pupuk Magnesium Dan Nitrogen

    OpenAIRE

    Panjaitan, Lily Damery

    2014-01-01

    The aim of the present study is to investigate the physiological and morphological responses to three concentration of magnesium (low,medium and high) and two level nitrogen (with or without) fertilization of oil palm. Factorial Randomized Design was used 2 factors. The oil palm was 8 years old. The treatmenst with nitrogen and magnesium fertilizer has been starting since 2007-2013. Observation was started on July-September 2013 at Physiology laboratory of North Sumtera University. Total samp...

  14. Effects of segregation of primary alloying elements on the creep response in magnesium alloys

    DEFF Research Database (Denmark)

    Huang, Y.D.; Dieringa, H.; Hort, N.; Leil, T.A.; Kainer, K.U.; Liu, Yi-Lin

    2008-01-01

    The segregation of primary alloying elements deteriorates the high temperature creep resistance of magnesium alloys. Annealing at high temperatures alleviating their segregations can improve the creep resistance. Present investigation on the effect of segregation of primary alloying elements on the...... creep response may provide some useful information about how to improve the creep resistance of magnesium alloys in the future. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved....

  15. Study on the isothermal forging process of MB26 magnesium alloy adaptor

    OpenAIRE

    Xu Wenchen; Yang Chuan; Shaninst Debin; Xu Fuchang; Wang Guan; Guo Bin

    2015-01-01

    The isothermal forging process is an effective method to manufacture complex-shaped components of hard-to-work materials, such as magnesium alloys. This study investigates the isothermal forging process of an MB26 magnesium alloy adaptor with three branches. The results show that two-step forging process is appropriate to form the adaptor forging, which not only improves the filling quality but also reduces the forging load compared with one-step forging process. Moreover, the flow line is di...

  16. Struvite precipitation and phosphorus removal using magnesium sacrificial anode.

    Science.gov (United States)

    Kruk, Damian J; Elektorowicz, Maria; Oleszkiewicz, Jan A

    2014-04-01

    Struvite precipitation using magnesium sacrificial anode as the only source of magnesium is presented. High-purity magnesium alloy cast anode was found to be very effective in recovery of high-quality struvite from water solutions and from supernatant of fermented waste activated sludge from a wastewater treatment plant that does not practice enhanced biological phosphorus removal. Struvite purity was strongly dependent on the pH and the electric current density. Optimum pH of the 24 mM phosphorus and 46 mM ammonia solution (1:1.9 P:N ratio) was in the broad range between 7.5 and 9.3, with struvite purity exceeding 90%. Increasing the current density resulted in elevated struvite purity. No upper limits were observed in the studied current range of 0.05-0.2 A. Phosphorus removal rate was proportional to the current density and comparable for tests with water solutions and with the supernatant from fermented sludge. The highest P-removal rate achieved was 4.0 mg PO4-P cm(-2) h(-1) at electric current density of 45 A m(-2). Initial substrate concentrations affected the rate of phosphorus removal. The precipitated struvite accumulated in bulk liquid with significant portions attached to the anode surface from which regular detachment occurred. PMID:24387911

  17. Fracture analysis of selected magnesium alloys after different testing methods

    Directory of Open Access Journals (Sweden)

    L. Cížek

    2007-10-01

    Full Text Available Purpose: of this paper is to extend a complex evaluation of magnesium alloys which requires very often knowledge mechanical properties. These properties are connected with microstructure that is influenced by metallurgical and technological factors and conditions of exploitation. Very important information for design and exploitation of these alloys is knowledge of fracture characteristics.Design/methodology/approach: Testing methods used magnesium alloys were based on tensile test and torsion test. The methods of the light microscopy and SEM for metallographic and fracture analyses of alloys after testing were used.Findings: Objective of this work consisted in determination of changes of mechanical properties and fracture characteristics of magnesium alloy in dependence on testing methods. Mg-Al alloy with graduate aluminium content as cast state and after heat treatment was used. It was confirmed that during heating at chosen temperatures there occurs partial dissolution of minority phases.Research limitations/implications: According to the alloys characteristic, the applied cooling rate and alloy additions seems to be a good compromise for mechanical properties and microstructures, nevertheless further tests should be carried out in order to examine different cooling rates and parameters of solution treatment process and aging process.Practical implications: The results may be utilized for a relation between plastic and strength properties of the investigated material in process of research and manufacturingOriginality/value: These results contribute to complex evaluation of properties magnesium alloys namely for explanation of fracture mechanism in changing condition of testing and exploitation. The results of this paper are determined for research workers deal by development new exploitations of magnesium alloys.

  18. Development of a magnesium secondary alloy system for mixed magnesium post-consumer scrap

    International Nuclear Information System (INIS)

    Six alloys were prepared by high pressure die casting in order to develop a magnesium secondary alloy system for mixed post-consumer scrap. The alloys were investigated with regard to intermetallic phases, grain structures, mechanical properties and performance in the salt spray test. The results are discussed in relation to the characteristics of the high pressure die casting process. The effect of contamination by copper and compensation for this effect by the addition of zinc were thoroughly investigated for the most promising alloy. It is evident that the alloying elements strontium, silicon and calcium are incorporated in the ternary Zintl phase Sr6.33Mg16.67Si13, while aluminium, zinc, copper and magnesium form the tau-phases Mg32(Alx,Cu1−x)49 and Mg32(Al,Zn)49. The two tau-phases can merge due to isomorphism. Mg32(Al,Zn)49 ensures improved corrosion resistance after the addition of copper

  19. Development of a magnesium secondary alloy system for mixed magnesium post-consumer scrap

    Energy Technology Data Exchange (ETDEWEB)

    Fechner, Daniel, E-mail: dfechner@tuev-nord.de; Blawert, Carsten; Hort, Norbert; Dieringa, Hajo; Kainer, Karl Ulrich

    2013-08-01

    Six alloys were prepared by high pressure die casting in order to develop a magnesium secondary alloy system for mixed post-consumer scrap. The alloys were investigated with regard to intermetallic phases, grain structures, mechanical properties and performance in the salt spray test. The results are discussed in relation to the characteristics of the high pressure die casting process. The effect of contamination by copper and compensation for this effect by the addition of zinc were thoroughly investigated for the most promising alloy. It is evident that the alloying elements strontium, silicon and calcium are incorporated in the ternary Zintl phase Sr{sub 6.33}Mg{sub 16.67}Si{sub 13}, while aluminium, zinc, copper and magnesium form the tau-phases Mg{sub 32}(Al{sub x},Cu{sub 1−x}){sub 49} and Mg{sub 32}(Al,Zn){sub 49}. The two tau-phases can merge due to isomorphism. Mg{sub 32}(Al,Zn){sub 49} ensures improved corrosion resistance after the addition of copper.

  20. 改性氯氧镁水泥砂石混凝土强度的试验研究%Experimental Investigation on Strength Development of Modified Magnesium Oxychloride Cement Concrete

    Institute of Scientific and Technical Information of China (English)

    乔宏霞; 刘尧; 周茗如; 余红发; 冯坚

    2012-01-01

    Basing on different MgO/MgCl2 and H2O/MgCl2 molar ratios, the magnesium oxychloride cement(MOC) concrete was formed by adding the mixture of MgO, gravel, sand, water-resisting admixture and three kinds of mineral admixtures ( fly ash, silica fume and mineral powder) into magnesium chloride solution (MCS). The test blocks were demoulded and tested at 7 d, 14 d, 28 d, 56 d, 90 d and 128 d aging time. The rules of strength develop was summarized as early and late strength development. The patterns of compressive strength development showed the same trend, but the numerical value varied with different mineral admixtures, as the concrete with fly ash performed the highest, while that with mineral powder showed the lowest. The Late development of all mixture proportions fluctuated. That was, the strength dropped at a certain aging time, and then the development was resumed as the curing proceeded. XRD, SEM and EDS was used to analyze the micro-mechanism, and the dense gel phase was found in MOC concrete with fly ash. The strength loss, as the result of the active magnesia, was overall controllable due to the existence of WRA.%基于不同的MgO/MgCl2 、H2O/MgCl2物质的量比,试验中混合不同量的氧化镁、砂子、石子、抗水剂以及三种传统矿物掺合料拌制氯氧镁水泥混凝土,并测定其早期(7~28 d)和后期(28 ~ 128 d)抗压强度.试验证明,添加不同矿物掺合科(硅灰,矿粉,粉煤灰)镁水泥强度发展趋势相同但强度发展程度不同,其中以粉煤灰混凝土强度最高.由于复合抗水剂的存在,早期吸潮返卤被抑制,强度发展良好.后期混凝土强度发生下降,随着养护进行,强度又恢复发展.通过微观手段(X射线衍射、扫描电镜和能谱图)发现,含有粉煤灰的镁水泥混凝土样品微观结构存在致密凝胶相.

  1. The Investigation of Magnesium Perchlorate/Iron Phase-mineral Mixtures as a Possible Source of Oxygen and Chlorine Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars

    Science.gov (United States)

    Sutter, B.; Heil, E.; Archer, P. D.; Ming, D. W.; Eigenbrode, J. L.; Franz, H. B.; Glavin, D. P.; McAdam, A. C.; Mahaffy, P. R.; Niles, P. B.; Stern, J. C.; Navarro-Gonzalez, R.; McKay, C. P.

    2014-01-01

    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover detect-ed O2 and HCl gas releases from the Rocknest (RN) eolian bedform and the John Klein (JK) and Cumber-land (CB) drill hole materials in Gale Crater (Fig. 1) [1,2]. Chlorinated hydrocarbons have also been detect-ed by the SAM quadrupole mass spectrometer (QMS) and gas chromatography/mass spectrometer (GCMS) [1,2,3,4]. These detections along with the detection of perchlorate (ClO4(-)) by the Mars Phoenix Lander's Wet Chemistry Laboratory (WCL) [5] suggesting perchlo-rate is a possible candidate for evolved O2 and chlorine species. Laboratory thermal analysis of individual per-chlorates has yet to provide an unequivocal tempera-ture match to the SAM O2 and HCl release data [1,2]. Catalytic reactions of Fe phases in the Gale Crater ma-terial with perchlorates can potentially reduce the de-composition temperatures of these otherwise pure per-chlorate/chlorate phases [e.g., 6,7]. Iron mineralogy found in the Rocknest materials when mixed with Ca-perchlorate was found to cause O2 release temperatures to be closer match to the SAM O2 release data and enhance HCl gas releases. Exact matches to the SAM data has unfortnunately not been achieved with Ca-perchlorate-Fe-phase mixtures [8]. The effects of Fe-phases on magnesium perchlorate thermal decomposi-tion release of O2 and HCl have not been evaluated and may provide improved matches to the SAM O2 and HCl release data. This work will evaluate the thermal decomposition of magnesium perchlorate mixed with fayalite/magnetite phase and a Mauna Kea palagonite (HWMK 919). The objectives are to 1) summarize O2 and HCl releases from the Gale Crater materials, and 2) evaluate the O2 and HCl releases from the Mg-perchlorate + Fe phase mixtures to determine if Mg-perchlorate mixed with Fe-phases can explain the Gale Crater O2 and HCl releases.

  2. Cathodic phosphate coating containing nano zinc particles on magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A technology for preparation of a cathodic phosphate coating mainly containing nano metallic zinc particles and phosphate compounds on magnesium alloy was developed.The influence of cathodic current density on the microstructure of the cathodic phosphate coating Was investigated.The results show that the crystals of the coating are finer and the microstructures of the outer surface of the coatings are zigzag at the cathodic density of 0.2-0.5 A/dm2.The content of nano metallic zinc particles in the coating decreases with the increase of the thickness of the coatings and tends to be zero when the coating thickness is 4.14 μm.The cathodic phosphate coating was applied to be a transition coating for improving the adhesion between the paints and the magnesium alloys.The formation mechanism of the cathodic phosphate coating was investigated as well.

  3. Microstructure of MCMgAl12Zn1 magnesium alloy

    Directory of Open Access Journals (Sweden)

    Dobrzański L. A.

    2007-01-01

    Full Text Available In this paper is presented the structure of the cast magnesium alloys as cast state and after heat treatment cooled with different cooling rate, depending on the cooling medium (furnace, water, air. For investigations samples in shape of 250x150x25 mm plates were used. The structure have been study in the light microscope, scanning electron microscope equipped with an electron back scattering facility. The effects of the addition of Al on the microstructure were also studied. In the analysed alloys a structure of α solid solution and fragile phase β(Mg17Al12 occurred mainly on grain borders as well as eutectic and phase with Mn, Fe and Si. Investigation are carried out for the reason of chemical composition influence and precipitation processes influence to the structure and mechanical properties of the magnesium cast alloys with different chemical composition in as cast alloys and after heat treatment.

  4. Magnesium growth in magnesium deuteride thin films during deuterium desorption

    Energy Technology Data Exchange (ETDEWEB)

    Checchetto, R., E-mail: riccardo.checchetto@unitn.it [Dipartimento di Fisica and CNISM, Università di Trento, Via Sommarive 14, I-38123 Trento (Italy); Miotello, A. [Dipartimento di Fisica and CNISM, Università di Trento, Via Sommarive 14, I-38123 Trento (Italy); Mengucci, P.; Barucca, G. [Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Università Politecnica delle Marche, I-60131 Ancona (Italy)

    2013-12-15

    Highlights: ► Highly oriented Pd-capped magnesium deuteride thin films. ► The MgD{sub 2} dissociation was studied at temperatures not exceeding 100 °C. ► The structure of the film samples was analyzed by XRD and TEM. ► The transformation is controlled by the re-growth velocity of the Mg layers. ► The transformation is thermally activated, activation energy value of 1.3 ± 0.1 eV. -- Abstract: Pd- capped nanocrystalline magnesium thin films having columnar structure were deposited on Si substrate by e-gun deposition and submitted to thermal annealing in D{sub 2} atmosphere to promote the metal to deuteride phase transformation. The kinetics of the reverse deuteride to metal transformation was studied by Thermal Desorption Spectroscopy (TDS) while the structure of the as deposited and transformed samples was analyzed by X-rays diffraction and Transmission Electron Microscopy (TEM). In Pd- capped MgD{sub 2} thin films the deuteride to metal transformation begins at the interface between un-reacted Mg and transformed MgD{sub 2} layers. The D{sub 2} desorption kinetics is controlled by MgD{sub 2}/Mg interface effects, specifically the re-growth velocity of the Mg layers. The Mg re-growth has thermally activated character and shows an activation energy value of 1.3 ± 0.1 eV.

  5. Production of lightweight ceramisite from iron ore tailings and its performance investigation in a biological aerated filter (BAF) reactor

    International Nuclear Information System (INIS)

    The few reuse and large stockpile of iron ore tailings (IOT) led to a series of social and environmental problems. This study investigated the possibility of using the IOT as one of starting materials to prepare lightweight ceramisite (LWC) by a high temperature sintering process. Coal fly ash (CFA) and municipal sewage sludge (SS) were introduced as additives. The LWC was used to serve as a biomedium in a biological aerated filter (BAF) reactor for municipal wastewater treatment, and its purification performance was examined. The effects of sintering parameters on physical properties of the LWC, and leaching concentrations of heavy metals from the LWC were also determined. The microstructure and the phase composition of the LWC were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results revealed that: (1) IOT could be used to produce the LWC under the optimal sintering parameters; (2) the leaching concentrations of heavy metals from the LWC were well below their respective regulatory levels in the China Environmental Quality Standards for Surface Water (CEQS); and (3) the BAF reactor with the LWC serving as the biomedium achieved high removal efficiencies for CODCr (>92%), NH4+-N (>62%) and total phosphate (T-P) (>63%). Therefore, the LWC produced from the IOT was suitable to serve as the biomedium in the municipal wastewater treatment.

  6. Preface of the "Symposium on Mathematical Models and Methods to investigate Heterogeneity in Cell and Cell Population Biology"

    Science.gov (United States)

    Clairambault, Jean

    2016-06-01

    This session investigates hot topics related to mathematical representations of cell and cell population dynamics in biology and medicine, in particular, but not only, with applications to cancer. Methods in mathematical modelling and analysis, and in statistical inference using single-cell and cell population data, should contribute to focus this session on heterogeneity in cell populations. Among other methods are proposed: a) Intracellular protein dynamics and gene regulatory networks using ordinary/partial/delay differential equations (ODEs, PDEs, DDEs); b) Representation of cell population dynamics using agent-based models (ABMs) and/or PDEs; c) Hybrid models and multiscale models to integrate single-cell dynamics into cell population behaviour; d) Structured cell population dynamics and asymptotic evolution w.r.t. relevant traits; e) Heterogeneity in cancer cell populations: origin, evolution, phylogeny and methods of reconstruction; f) Drug resistance as an evolutionary phenotype: predicting and overcoming it in therapeutics; g) Theoretical therapeutic optimisation of combined drug treatments in cancer cell populations and in populations of other organisms, such as bacteria.

  7. Morphological and biological investigation of two pioneer Ips bark beetles in natural spruce forests in Qinghai Province, northwest China

    Institute of Scientific and Technical Information of China (English)

    LIU Li; WU Jian; LUO You-qing; LI Zhen-yu; WANG Guo-cang; HAN Fu-zhong

    2008-01-01

    Bark beetle species in natural stands of spruce, Picea crassifolia (Kom.) were investigated in Maixiu Forest Park, Qinghai Province, northwest China, during 2005 and 2007. Two pioneer lps species, Ips nitidus Eggers and lps shangrila Cognato and Sun were found. L nitidus occurs naturally in northwest China. L shangrila is a new species in the world. In the past, it was confused with I. mannsfeldi Wachtl in China. The damage of these two Ips species has been very severe in Maixiu and the morphological and biological characteristics were studied. L nitidus starts to fly in early May and prefers the mid to lower part of the host tree to colonize as its habitat. L shangrila always infests from the top of the trunk, especially in branches larger than 3 em in diameter in the crowns and sometimes even colonizes entire young trees. The two Ips species are the most destructive secondary bark beetles on P. crassifolia and always cause mortality of trees by their cooperation.

  8. Investigation of the soluble metals in tissue as biological response pattern to environmental pollutants (Gammarus fossarum example).

    Science.gov (United States)

    Filipović Marijić, Vlatka; Dragun, Zrinka; Sertić Perić, Mirela; Matoničkin Kepčija, Renata; Gulin, Vesna; Velki, Mirna; Ečimović, Sandra; Hackenberger, Branimir K; Erk, Marijana

    2016-07-01

    In the present study, Gammarus fossarum was used to investigate the bioaccumulation and toxic effects of aquatic pollutants in the real environmental conditions. The novelty of the study is the evaluation of soluble tissue metal concentrations in gammarids as indicators in early assessment of metal exposure. In the Sutla River, industrially/rurally/agriculturally influenced catchment in North-Western Croatia, physico-chemical water properties pointed to disturbed ecological status, which was reflected on population scale as more than 50 times lower gammarid density compared to the reference location, Črnomerec Stream. Significantly higher levels of soluble toxic metals (Al, As, Cd, Pb, Sb, Sn, Sr) were observed in gammarids from the Sutla River compared to the reference site and reflected the data on higher total dissolved metal levels in the river water at that site. The soluble metal estimates were supplemented with the common multibiomarker approach, which showed significant biological responses for decreased acetylcholinesterase activity and increased total soluble protein concentrations, confirming stressed environmental conditions for biota in the Sutla River. Biomarker of metal exposure, metallothionein, was not induced and therefore, toxic effect of metals was not confirmed on molecular level. Comparable between-site pattern of soluble toxic metals in gammarids and total dissolved metal levels in water suggests that prior to biomarker response and observed toxic impact, soluble metals in tissue might be used as early warning signs of metal impact in the aquatic environment and improve the assessment of water quality. PMID:27060638

  9. A Simple and Low-Cost Monitoring System to Investigate Environmental Conditions in a Biological Research Laboratory.

    Science.gov (United States)

    Gurdita, Akshay; Vovko, Heather; Ungrin, Mark

    2016-01-01

    Basic equipment such as incubation and refrigeration systems plays a critical role in nearly all aspects of the traditional biological research laboratory. Their proper functioning is therefore essential to ensure reliable and repeatable experimental results. Despite this fact, in many academic laboratories little attention is paid to validating and monitoring their function, primarily due to the cost and/or technical complexity of available commercial solutions. We have therefore developed a simple and low-cost monitoring system that combines a "Raspberry Pi" single-board computer with USB-connected sensor interfaces to track and log parameters such as temperature and pressure, and send email alert messages as appropriate. The system is controlled by open-source software, and we have also generated scripts to automate software setup so that no background in programming is required to install and use it. We have applied it to investigate the behaviour of our own equipment, and present here the results along with the details of the monitoring system used to obtain them. PMID:26771659

  10. A systematic investigation on biological activities of a novel double zwitterionic Schiff base Cu(II) complex

    Science.gov (United States)

    Thalamuthu, S.; Annaraj, B.; Neelakantan, M. A.

    2014-01-01

    Double zwitterionic amino acid Schiff base, o-vanillylidene-L-histidine (OVHIS) and its copper complex (CuOVHIS) have been synthesized and characterized. CuOVHIS has distorted octahedral geometry, and OVHIS coordinates the copper ion in a tetradentate manner (N2O2). The pKa of OVHIS in aqueous solution was studied by potentiometric and spectrophotometric methods. DNA binding behavior of the compounds was investigated using spectrophotometric, cyclic voltammetric, and viscosity methods. The efficacy of DNA cleaving nature was tested on pUC19 DNA. The in vitro biological activity was tested against various micro organisms. The effect of CuOVHIS on the surface feature of Escherichia coli was analyzed by SEM. DPPH assay studies revealed that CuOVHIS has higher antioxidant activity. OVHIS inhibits proliferation of HCT117 cells with half maximal inhibition (IC50) of 71.15 ± 0.67. Chelation of OVHIS with Cu(II) ion enhances the inhibition of proliferation action (IC50 = 53.14 ± 0.67).

  11. Investigation of the effect of free ammonia concentration upon leachate treatment by shortcut biological nitrogen removal process.

    Science.gov (United States)

    Chung, Jinwook; Bae, Wookeun; Lee, Yong-Woo; Ko, Gwang-Beom; Lee, Sang-Uk; Park, Seong-Jun

    2004-01-01

    A shortcut biological nitrogen removal (SBNR) process was operated to treat an ammonium rich landfill leachate using a pilot-scale reactor. The SBNR process was intended to oxidize ammonia to nitrite and, then, to reduce it to nitrogen gas. When the hydraulic retention time was 4-3 days, a half of the ammonium oxidized was accumulated as nitrite in the oxidation tank. The nitrite was denitrified completely in the anoxic tank when recycled. The average free ammonia (FA) concentration in the ammonium oxidation tank was 3.7 mg/L. The specific substrate utilization rates of ammonium oxidizers and nitrite oxidizers were investigated at varying FA concentrations through batch experiments. The highest specific ammonium oxidation rate was observed when the FA concentration was 10 mg/L. The rate decreased slightly when the FA concentration was increased to 20 or 50 mg/L, or decreased significantly when it was 5 mg/L. In case of nitrite oxidation, the specific nitrite utilization rate decreased significantly with increasing FA concentration up to 10 mg/L. Consequently, the optimal FA concentration in leachate treatment was 10 mg/L for maximum nitrite accumulation and maximum ammonium removal, or 5 mg/L for lower ammonium concentration and reasonable nitrite accumulation. PMID:15242116

  12. Exoelectron emission from magnesium surfaces

    Science.gov (United States)

    Klar, F.; Bansmann, J.; Glaefeke, H.; Fitting, H.-J.; Meiwes-Broer, K.-H.

    1999-12-01

    Clean magnesium surfaces were created by evaporating Mg onto silicon wafers. When exposing the Mg surface to a low oxygen partial pressure, an exoelectron emission (EEE) is observed after a time delay of the order of several hours after evaporation. On a much shorter time scale, similar effects in exoemission from Mg and alkali metals have been observed previously. The results are discussed within a 'potential emission' model of exoelectrons during oxygen capture at the pure Mg surface, but extending the model by including an escape mechanism. A macroscopic quantitative description of the model is given, which is in good agreement with our measurements.

  13. Biological investigation of the platinum(II)-[*I]iodohistamine complexes of potential synergistic anti-cancer activity

    International Nuclear Information System (INIS)

    Cisplatin chemotherapy in combination with external irradiation or with low-dose continuos internal radiotherapy produces significant supra-additive treatment effects towards several tumor cells. The purpose of our research is to develop a new class of platinum-based anticancer drugs containing moieties of synergistic potency such as platinum core and a radiotherapeutic isotope which, delivered directly to the tumorous cells by a specifically designed vectors, should produce a local enhancement of therapeutic dose. Thus, we have synthesized a new platinum-iodohistamine complex and its radioactive analogues labeled with I-125 and I-131. In the present study some biological properties of those compounds have been investigated. The in vitro screening study pointed out that non-radioactive platinum-iodohistamine complex possesses high cytostatic activity against COLO-205 cells, and moderate activity against HL-60 cell line. No cytotoxicity was observed against MOLT-4 and L-1210 cells, as well as against VERO normal cells. The biodistribution of intravenously administered radioactive platinum-[131I]-iodohistamine complex to normal rats revealed the highest accumulation in the liver (c.a. 40%ID). Intraperitoneal injections of the complex to tumor-bearing C3H mice resulted in scattering of the dose in the organs (mainly in GIT, liver, kidney). The retention of radioactive complex in neoplastic tissue was 3-4 times higher than in normal muscular tissue, although exhibited the tendency to decrease with time post injection. The results of the present study show promising features of the newly developed platinum-iodohistamine complexes and justify prospective investigation of in vivo anticancer potency on animal models of solid tumors

  14. Magnesium removal in the electrolytic zinc industry

    NARCIS (Netherlands)

    Booster, J.L.

    2003-01-01

    Electrolytic zinc plants need to take measures to control the magnesium content in their process liquors, because the natural magnesium bleed does not balance the input from concentrates. Presently used methods are environmentally unfriendly (due to the production of large amounts of waste gypsum) o

  15. Infrared measurement and simulation of magnesium alloy welding temperature field

    Institute of Scientific and Technical Information of China (English)

    LIU; Liming; CHI; Mingsheng; HUANG; Ruisheng; SONG; Gang

    2005-01-01

    The welding temperature field of magnesium alloy AZ31 welded by TIG was measured with the uncooled infrared (IR) thermal imaging technology. The variables in the mathematic mode of welding temperature fields were revised by IR temperature data. Based on the results of simulation, the loss of temperature fields caused by arc interfered was compensated, and a whole temperature field was achieved, which provided a precise and powerful foundation for the investigation of microstructure of the joints.

  16. Microstructure of MCMgAl12Zn1 magnesium alloy

    OpenAIRE

    Dobrzański L.A.; Tański T.; Čížek L.

    2007-01-01

    In this paper is presented the structure of the cast magnesium alloys as cast state and after heat treatment cooled with different cooling rate, depending on the cooling medium (furnace, water, air). For investigations samples in shape of 250x150x25 mm plates were used. The structure have been study in the light microscope, scanning electron microscope equipped with an electron back scattering facility. The effects of the addition of Al on the microstructure were also studied. In the analysed...

  17. Radiation induced optical centres in magnesium aluminate spinel ceramics

    International Nuclear Information System (INIS)

    There were investigated the optical absorption centers formation in magnesium aluminate spinel ceramics under irradiation with UV-light, X-, and gamma-rays. The lithium fluoride doped ceramics were produced by using hot-pressing technology. It was revealed that generation by irradiation changes in optical absorption spectra can be used for detection of invisible point defects in prepared ceramics, their distribution through the bulk of spinel disk, and predict the behavior of ceramics in different radiation fields.

  18. Efficacy of oral magnesium treatment on primary fibromyalgia syndrome

    OpenAIRE

    Turan, Yasemin; Koçyiğit, Hikmet; Ekinci, Seçil; Bayram, Korhan Barış; Gürgan, Alev; Altundal, Yasin; Atay, Ayşenur

    2009-01-01

    Objective: The aim of this study was to investigate the effects of oral magnesium treatment on clinical findings such as number of sensitive points, severity of pain and functional capacity in primary Fibromyalgia syndrome patients. Material and Methods: Twenty-five primary fibromyalgia syndrome patients (24 female, 1 male) were enrolled to the study. Patients were examined in terms of pain in rest and activity, number of sensitive points and functional capacity. Fibromyalgia Impact Questi...

  19. Infrared spectroscopy studies of magnesium aluminates spinel crystals

    OpenAIRE

    Kobyakov, V.A.; Patochkina, O. L.; Gritsyna, V.T.

    2012-01-01

    The reflectance and transmittance spectra for magnesium aluminates spinel single crystals MgO·nAl2O3 and ceramics in the IR spectral range were measured to investigate the nature of vibration modes of constituent ions and incorporated hydrogen. The variation of intensity of registered bands in spinel of stoichiometric and nonstoichiometric compositions and spinel ceramics was obtained and interpreted in terms of vibration modes of divalent and trivalent cations in different coordinat...

  20. Microstructure 2007of WE43 casting magnesium alloy

    Directory of Open Access Journals (Sweden)

    A. Kiełbus

    2007-03-01

    Full Text Available Purpose: WE43 is a high-strength magnesium alloy characterized by good mechanical properties both at an ambient and elevated temperature (up to 300°C. It contains mainly yttrium and neodymium. The aim of this paper is to present the results of research on the microstructure of the WE43 magnesium alloy in an as-cast condition.Design/methodology/approach: For the microstructure observation, a Reichert metallographic microscope MeF2 and a HITACHI S-3400N scanning electron microscope with a Thermo Noran EDS equipped with SYSTEM SIX were used. A qualitative phase analysis was performed with a JEOL JDX-7S diffractometer. Microstrucutral examinations were performed JEOL 3010 transmission electron microscope.Findings: Based on the investigation carried out it was found that the microstructure of WE43 alloy after continuous casting consists of α-Mg matrix and irregular precipitates of Mg41Nd5, rectangular particles of MgY phase, particles of Mg24Y5, longitudinal precipitates of β (Mg14Nd2Y compound at grain boundaries and the grain interiors. All of these phases contain yttrium and neodymium. Research limitations/implications: Future researches should contain investigations of the influence of heat treatment parameters on microstructure, corrosion resistance and mechanical properties of WE43 alloy.Practical implications: WE43 magnesium alloy is used in the aircraft industry, for wheels, engine casings, gear box casings and rotor heads in helicopters. Results of investigation may be useful for development casting technology of the Mg-Y-Nd alloys.Originality/value: The results of the researches make up a basis for the next investigations of magnesium alloys with addition of Y and Nd designed to exploitation at temperature to 300°C.

  1. High temperature deformation mechanisms in pure magnesium studied by nanoindentation

    International Nuclear Information System (INIS)

    The effect of temperature on the main deformation mechanisms of pure magnesium (Mg) was investigated using nanoindentation combined with atomic force microscopy, electron backscatter diffraction and finite element crystal plasticity simulations. While twinning is clearly apparent near the indents performed at room temperature, almost no twinning activity was detected at 300 °C. The analysis of the residual imprints confirms that the decrease of the twin activity with temperature is compensated by a profuse activation of the prismatic slip systems

  2. Cell Adhesion on Surface-Functionalized Magnesium.

    Science.gov (United States)

    Wagener, Victoria; Schilling, Achim; Mainka, Astrid; Hennig, Diana; Gerum, Richard; Kelch, Marie-Luise; Keim, Simon; Fabry, Ben; Virtanen, Sannakaisa

    2016-05-18

    The biocompatibility of commercially pure magnesium-based (cp Mg) biodegradable implants is compromised of strong hydrogen evolution and surface alkalization due to high initial corrosion rates of cp Mg in the physiological environment. To mitigate this problem, the addition of corrosion-retarding alloying elements or coating of implant surfaces has been suggested. In the following work, we explored the effect of organic coatings on long-term cell growth. cp Mg was coated with aminopropyltriehtoxysilane + vitamin C (AV), carbonyldiimidazole (CDI), or stearic acid (SA). All three coatings have been previously suggested to reduce initial corrosion and to enhance protein adsorption and hence cell adhesion on magnesium surfaces. Endothelial cells (DH1+/+) and osteosarcoma cells (MG63) were cultured on coated samples for up to 20 days. To quantify Mg corrosion, electrochemical impedance spectroscopy (EIS) was measured after 1, 3, and 5 days of cell culture. We also investigated the speed of initial cell spreading after seeding using fluorescently labeled fibroblasts (NIH/3T3). Hydrogen evolution after contact with cell culture medium was markedly decreased on AV- and SA-coated Mg compared to uncoated Mg. These coatings also showed improved cell adhesion and spreading after 24 h of culture comparable to tissue-treated plastic surfaces. On AV-coated cp Mg, a confluent layer of endothelial cells formed after 5 days and remained intact for up to 20 days. Together, these data demonstrate that surface coating with AV is a viable strategy for improving long-term biocompatibility of cp Mg-based implants. EIS measurements confirmed that the presence of a confluent cell layer increased the corrosion resistance. PMID:27089250

  3. Study of second phase in bioabsorbable magnesium alloys: Phase stability evaluation via Dmol3 calculation

    Directory of Open Access Journals (Sweden)

    Huazhe Yang

    2013-11-01

    Full Text Available Thermodynamical stabilities of four conventional second phases as well as magnesium matrix in bioabsorbable magnesium alloys were investigated theoretically via computer calculation method. Model of individual phase and systems including phase and four water molecular (phase-4H2O were established to simulate the in vitro and in vivo environment. Local orbital density functional theory approach was applied to calculate the total energy for the individual phase and phase-4H2O system. The results demonstrated that all the second phases possessed higher phase stability compared with magnesium matrix, but the phase stability was quite different for different types of second phases or second phase-4H2O systems. Furthermore, a schematic process of inflammation reaction caused by magnesium alloy implants was proposed for the further evaluation on biocompatibility of different second phases.

  4. Effect of bicarbonate on biodegradation behaviour of pure magnesium in a simulated body fluid

    International Nuclear Information System (INIS)

    The effect of bicarbonate on biodegradation of pure magnesium in a simulated body fluid is investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, polarization curve and electrochemical impedance spectroscopy. The results show that magnesium biodegrades rapidly and non-uniformly during 27 h of immersion in four simulated body fluid solutions containing different concentrations of bicarbonate. The biodegradation rate first decreases and then increases with time. A small amount of bicarbonate in simulated body fluid has an inhibition effect on the Mg dissolution, while an overdose of bicarbonate addition activates the magnesium surface in the simulated body fluid. The interesting phenomena can be interpreted by a surface film model involving precipitation of calcium carbonate and further ionization of bicarbonate in the simulated body fluids, incorporation of calcium, carbonate and phosphate compounds in the surface film, and development of chloride-induced pitting corrosion damage on the magnesium with time

  5. Grain refinement of Mg-Al magnesium alloys by carbon inoculation

    Institute of Scientific and Technical Information of China (English)

    WANG Zhao-hui; KANG Yong-lin; ZHAO Hong-jin; XU Yue

    2006-01-01

    C2Cl6 was used as grain refiner for AM60 magnesium alloys. The effects of grain refinement process on chemical composition, microstructure, impact energy, hardness and mechanical properties of magnesium alloys were investigated with XRF spectrometer, optical and electronic microscopes, pendulum impact tester, hardness tester and MTS material testing machine. The results show that C2Cl6 has good effects on microstructure and mechanical properties of AM60 magnesium alloys. The optimum usage of C2Cl6 in AM60 for getting the best properties is 1.0%. The results of electronic microscopic examination and theoretical analyses show that Al4C3 should be the potent heterogeneous nucleant for Mg-Al magnesium alloys.

  6. A novel dual nickel coating on AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Magnesium alloys covered with metal coating display excellent corrosion resistance,wear resistance,conductivity and electromagnetic shielding properties.The electroless plating Ni-P as boRom layer following the electroplating nickel as surface layer on AZ91D magnesium alloy was investigated.The coating surface morphology was observed with SEM and the structure was analyzed with XRD.Electrochemical tests and salt spray tests were carried out to study the corrosion resistance.The experimental results indicate that the dual coating is uniform,compact and pore-free.The adhesion strength between magnesium alloy substrate and electroless plating Ni-P bottom layer and electroplating nickel surface layer is perfect.The corrosion resistance of AZ91D magnesium alloy is greatly improved after being protected with the dual coating.

  7. Mechanical degradation of porous titanium with entangled structure filled with biodegradable magnesium in Hanks' solution.

    Science.gov (United States)

    Li, Qiuyan; Jiang, Guofeng; Wang, Cunlong; Dong, Jie; He, Guo

    2015-12-01

    The degradation behavior of the porous titanium with entangled structure filled with biodegradable magnesium (p-Ti/Mg) in Hanks' solution was investigated. It was found that the p-Ti/Mg composite had higher strength than pure magnesium and porous titanium with entangled structure (p-Ti). Although the magnesium in p-Ti/Mg was completely dissolved in Hanks' solution after immersion for 104 h, the rest of the sample still maintained strength of about 86 MPa. Moreover, the produced porousness (due to magnesium-degradation) could provide channels for the ingrowth and transportation of bone cells. However, the high corrosion rate of p-Ti/Mg is still a problem when used as a candidate biomedical material, which needs further improvement. PMID:26354275

  8. Corrosion Behavior of Simulated HLW Glass in the Presence of Magnesium Ion

    Directory of Open Access Journals (Sweden)

    Toshikatsu Maeda

    2011-01-01

    Full Text Available Static leach tests were conducted for simulated HLW glass in MgCl2 solution for up to 92 days to investigate the dissolution mechanism of HLW glass under coastal repository condition. Under the condition that magnesium ion exists in leachate, the dissolution rate of the glass did not decrease with time during leaching, while the rate decreased when the magnesium ion depleted in the leachate. In addition, altered layer including magnesium and silica was observed at the surface of the glass after the leach tests. The present results imply that dissolution of the glass is accompanied with formation of magnesium silicate consuming silica, a glass network former. As a consequence, the glass dissolved with an initial high dissolution rate.

  9. Improved cytotoxicity testing of magnesium materials

    International Nuclear Information System (INIS)

    Metallic magnesium (Mg) and its alloys are highly suitable for medical applications as biocompatible and biodegradable implant materials. Magnesium has mechanical properties similar to bone, stimulates bone regeneration, is an essential non-toxic element for the human body and degrades completely within the body environment. In consequence, magnesium is a promising candidate as implant material for orthopaedic applications. Protocols using the guideline of current ISO standards should be carefully evaluated when applying them for the characterization of the cytotoxic potential of degradable magnesium materials. For as-cast material we recommend using 10 times more extraction medium than recommended by the ISO standards to obtain reasonable results for reliable cytotoxicity rankings of degradable materials in vitro. In addition primary isolated human osteoblasts or mesenchymal stem cells should be used to test magnesium materials.

  10. Improved cytotoxicity testing of magnesium materials

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Janine, E-mail: janine.fischer@hzg.de [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Department for Structural Research on Macromolecules, Max-Planck Str. 1, D - 21502 Geesthacht (Germany); Proefrock, Daniel [Helmholtz-Zentrum Geesthacht, Institute for Coastal Research, Department for Marine Bioanalytical Chemistry, Max-Planck Str. 1, D - 21502 Geesthacht (Germany); Hort, Norbert [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Department for Magnesium Processing, Max-Planck Str. 1, D - 21502 Geesthacht (Germany); Willumeit, Regine; Feyerabend, Frank [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Department for Structural Research on Macromolecules, Max-Planck Str. 1, D - 21502 Geesthacht (Germany)

    2011-06-25

    Metallic magnesium (Mg) and its alloys are highly suitable for medical applications as biocompatible and biodegradable implant materials. Magnesium has mechanical properties similar to bone, stimulates bone regeneration, is an essential non-toxic element for the human body and degrades completely within the body environment. In consequence, magnesium is a promising candidate as implant material for orthopaedic applications. Protocols using the guideline of current ISO standards should be carefully evaluated when applying them for the characterization of the cytotoxic potential of degradable magnesium materials. For as-cast material we recommend using 10 times more extraction medium than recommended by the ISO standards to obtain reasonable results for reliable cytotoxicity rankings of degradable materials in vitro. In addition primary isolated human osteoblasts or mesenchymal stem cells should be used to test magnesium materials.

  11. On the applicability of high strength self-tapping aluminium bolts in magnesium nut materials for automotive applications

    Energy Technology Data Exchange (ETDEWEB)

    Gerstmayr, G.; Leitner, H.; Eichlseder, W. [Mechanical Engineering, University of Leoben (Austria); Mori, G. [CD-Laboratory of Localized Corrosion - General, Analytical and Physical Chemistry, University of Leoben (Austria)

    2010-05-15

    High strength aluminium bolts made of AW 6056 T6, AW 7075 T6 and T79 have been investigated regarding the applicability in magnesium nut materials for automotive applications. With respect to galvanic corrosion all combinations of aluminium bolts with magnesium parts show superior corrosion properties when compared to galvanised steel bolts connected to magnesium. With respect to stress corrosion cracking (SCC) no aluminium bolt in contact with magnesium failed due to SCC. This is because of cathodic protection of aluminium alloy through magnesium. Even peak-tempered highest strengthened T6 7xxx aluminium bolts can be used for automotive applications when compressive residual stresses are present in the thread root of the bolts. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  12. The effect of sodium silicate concentration on microstructure and corrosion properties of MAO-coated magnesium alloy AZ31 in simulated body fluid

    OpenAIRE

    B. Salami; Afshar, A.; Mazaheri, A.

    2014-01-01

    In recent years, magnesium and its alloys are considered as biodegradable implants. However magnesium implants may rapidly corrode before the natural healing process of the tissue is completed. In this investigation, micro arc oxidation process has been studied for avoiding primary corrosion of the magnesium alloy in simulated body fluid. Anodized coating was formed on AZ31 alloy in nontoxic silicate-alkaline solution at constant current. The effects of silicate concentration and conductivity...

  13. Correlation of magnesium intake with metabolic parameters, depression and physical activity in elderly type 2 diabetes patients: a cross-sectional study

    OpenAIRE

    Huang Jui-Hua; Lu Yi-Fa; Cheng Fu-Chou; Lee John; Tsai Leih-Ching

    2012-01-01

    Abstract Background Type 2 diabetes mellitus is a major global public health problem in the worldwide and is increasing in aging populations. Magnesium intake may be one of the most important factors for diabetes prevention and management. Low magnesium intake may exacerbate metabolic abnormalities. In this study, the relationships of magnesium intake with metabolic parameters, depression and physical activity in elderly patients with type 2 diabetes were investigated. Methods This cross-sect...

  14. Magnesium supplement in pregnancy-induced hypertension: effects on maternal and neonatal magnesium and calcium homeostasis

    DEFF Research Database (Denmark)

    Rudnicki, M; Frølich, A; Fischer-Rasmussen, W

    1991-01-01

    The objective of this study was to evaluate the effect of low dose magnesium supplement upon maternal and fetal serum levels of mineral status in pregnancies complicated with hypertension (PIH). Twenty-five patients with PIH agreed to participate and were randomly allocated, in a double-blind man......The objective of this study was to evaluate the effect of low dose magnesium supplement upon maternal and fetal serum levels of mineral status in pregnancies complicated with hypertension (PIH). Twenty-five patients with PIH agreed to participate and were randomly allocated, in a double......-blind manner, either to intravenous magnesium for 2 days followed by oral magnesium (n = 12) until delivery or placebo (n = 13). In women supplemented with magnesium the level of magnesium increased from 0.74 to 1.02 mmol/l during the first 24 h of inclusion and simultaneously we observed an increased urinary...... loss of magnesium. Serum level and the urinary excretion of magnesium returned to pretreatment level at delivery. Maternal magnesium supplement increased the concentrations of magnesium in umbilical cord and neonatal blood 1 day after delivery. Serum ionized calcium did not change during the study...

  15. Systems biology investigation of cAMP modulation to increase SMN levels for the treatment of spinal muscular atrophy.

    Directory of Open Access Journals (Sweden)

    Sean G Mack

    Full Text Available Spinal muscular atrophy (SMA, a leading genetic cause of infant death worldwide, is an autosomal recessive disorder caused by the loss of SMN1 (survival motor neuron 1, which encodes the protein SMN. The loss of SMN1 causes a deficiency in SMN protein levels leading to motor neuron cell death in the anterior horn of the spinal cord. SMN2, however, can also produce some functional SMN to partially compensate for loss of SMN1 in SMA suggesting increasing transcription of SMN2 as a potential therapy to treat patients with SMA. A cAMP response element was identified on the SMN2 promoter, implicating cAMP activation as a step in the transcription of SMN2. Therefore, we investigated the effects of modulating the cAMP signaling cascade on SMN production in vitro and in silico. SMA patient fibroblasts were treated with the cAMP signaling modulators rolipram, salbutamol, dbcAMP, epinephrine and forskolin. All of the modulators tested were able to increase gem formation, a marker for SMN protein in the nucleus, in a dose-dependent manner. We then derived two possible mathematical models simulating the regulation of SMN2 expression by cAMP signaling. Both models fit well with our experimental data. In silico treatment of SMA fibroblasts simultaneously with two different cAMP modulators resulted in an additive increase in gem formation. This study shows how a systems biology approach can be used to develop potential therapeutic targets for treating SMA.

  16. Production of sorption functional media (SFM) from clinoptilolite tailings and its performance investigation in a biological aerated filter (BAF) reactor

    International Nuclear Information System (INIS)

    Highlights: ► Sorption functional media (SFM) were prepared using zeolite tailings. ► Two upflow BAFs were applied to treat municipal wastewater. ► SFM BAF brought a relative superiority to haydite reactor. ► SFM BAF has a stronger adaptability to low temperature (6–11°C) for NH3-N removal. ► The application provided a promising way in zeolite tailings utilization. -- Abstract: The few reuse and large stockpile of zeolite tailings led to a series of social and environmental problems. This study investigated the possibility of using the zeolite tailings as one of principal raw materials to prepare sorption functional media (SFM) by a high temperature sintering process. The SFM was used to serve as a biomedium in a biological aerated filter (BAF) reactor for domestic wastewater treatment, and its purification performance was examined. The physical, chemical and sorption properties of SFM were also determined. The microstructure of the SFM was analyzed by scanning electron microscopy (SEM). Results revealed that: (1) zeolite tailings could be used to produce the SFM under the optimal sintering parameters; (2) the sorption and desorption isotherm of ammonia nitrogen on SFM could be well described by the Langmuir formula; (3) in terms of removing organic matter, ammonia nitrogen, turbidity and colourity, the performance of the biofilter with SFM was superior to that with haydite; and (4) SFM BAF has a stronger adaptability to low temperature (6–11 °C) for NH3-N removal compared to haydite BAF. Therefore, the SFM produced from the zeolite tailings was suitable to serve as the biomedium in the domestic wastewater treatment

  17. Production of sorption functional media (SFM) from clinoptilolite tailings and its performance investigation in a biological aerated filter (BAF) reactor

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yan [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); School of Civil Engineering and Architecture, University of Jinan, Jinan 250022 (China); Qi, Jingyao, E-mail: qjy_hit@yahoo.cn [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Chi, Liying [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Wang, Dong [School of Civil Engineering and Architecture, University of Jinan, Jinan 250022 (China); Wang, Zhaoyang; Li, Ke; Li, Xin [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2013-02-15

    Highlights: ► Sorption functional media (SFM) were prepared using zeolite tailings. ► Two upflow BAFs were applied to treat municipal wastewater. ► SFM BAF brought a relative superiority to haydite reactor. ► SFM BAF has a stronger adaptability to low temperature (6–11°C) for NH{sub 3}-N removal. ► The application provided a promising way in zeolite tailings utilization. -- Abstract: The few reuse and large stockpile of zeolite tailings led to a series of social and environmental problems. This study investigated the possibility of using the zeolite tailings as one of principal raw materials to prepare sorption functional media (SFM) by a high temperature sintering process. The SFM was used to serve as a biomedium in a biological aerated filter (BAF) reactor for domestic wastewater treatment, and its purification performance was examined. The physical, chemical and sorption properties of SFM were also determined. The microstructure of the SFM was analyzed by scanning electron microscopy (SEM). Results revealed that: (1) zeolite tailings could be used to produce the SFM under the optimal sintering parameters; (2) the sorption and desorption isotherm of ammonia nitrogen on SFM could be well described by the Langmuir formula; (3) in terms of removing organic matter, ammonia nitrogen, turbidity and colourity, the performance of the biofilter with SFM was superior to that with haydite; and (4) SFM BAF has a stronger adaptability to low temperature (6–11 °C) for NH{sub 3}-N removal compared to haydite BAF. Therefore, the SFM produced from the zeolite tailings was suitable to serve as the biomedium in the domestic wastewater treatment.

  18. Microwave assisted synthesis and characterization of magnesium substituted calcium phosphate bioceramics

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Nida Iqbal [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan); Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Ijaz, Kashif; Zahid, Muniza; Khan, Abdul S. [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan); Abdul Kadir, Mohammed Rafiq [Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Hussain, Rafaqat [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johore (Malaysia); Anis-ur-Rehman [Department of Physics, COMSATS Institute of Information Technology, Chakshahzad Campus, Islamabad (Pakistan); Darr, Jawwad A. [Clean Materials Technology Group, Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Ihtesham-ur-Rehman [The Kroto Research Institute, North Campus, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom); Chaudhry, Aqif A., E-mail: aqifanwar@ciitlahore.edu.pk [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan)

    2015-11-01

    Hydroxyapatite is used extensively in hard tissue repair due to its biocompatibility and similarity to biological apatite, the mineral component of bone. It differs subtly in composition from biological apatite which contains other ions such as magnesium, zinc, carbonate and silicon (believed to play biological roles). Traditional methods of hydroxyapatite synthesis are time consuming and require strict reaction parameter control. This paper outlines synthesis of magnesium substituted hydroxyapatite using simple microwave irradiation of precipitated suspensions. Microwave irradiation resulted in a drastic decrease in ageing times of amorphous apatitic phases. Time taken to synthesize hydroxyapatite (which remained stable upon heat treatment at 900 °C for 1 h) reduced twelve folds (to 2 h) as compared to traditionally required times. The effects of increasing magnesium concentration in the precursors on particle size, surface area, phase-purity, agglomeration and thermal stability, were observed using scanning electron microscopy, BET surface area analysis, X-ray diffraction and photo acoustic Fourier transform infra-red spectroscopy. Porous agglomerates were obtained after a brief heat-treatment (1 h) at 900 °C. - Highlights: • Microwave irradiation of suspensions of calcium phosphates accelerated maturation. • Reactions took 2 h to complete as compared to 18 h required traditionally. • Magnesium contents higher than 1 wt.% lead to the presence of non-apatitic phases. • Agglomerates with micron and sub-micron porosity were obtained after heat-treatment.

  19. Microwave assisted synthesis and characterization of magnesium substituted calcium phosphate bioceramics

    International Nuclear Information System (INIS)

    Hydroxyapatite is used extensively in hard tissue repair due to its biocompatibility and similarity to biological apatite, the mineral component of bone. It differs subtly in composition from biological apatite which contains other ions such as magnesium, zinc, carbonate and silicon (believed to play biological roles). Traditional methods of hydroxyapatite synthesis are time consuming and require strict reaction parameter control. This paper outlines synthesis of magnesium substituted hydroxyapatite using simple microwave irradiation of precipitated suspensions. Microwave irradiation resulted in a drastic decrease in ageing times of amorphous apatitic phases. Time taken to synthesize hydroxyapatite (which remained stable upon heat treatment at 900 °C for 1 h) reduced twelve folds (to 2 h) as compared to traditionally required times. The effects of increasing magnesium concentration in the precursors on particle size, surface area, phase-purity, agglomeration and thermal stability, were observed using scanning electron microscopy, BET surface area analysis, X-ray diffraction and photo acoustic Fourier transform infra-red spectroscopy. Porous agglomerates were obtained after a brief heat-treatment (1 h) at 900 °C. - Highlights: • Microwave irradiation of suspensions of calcium phosphates accelerated maturation. • Reactions took 2 h to complete as compared to 18 h required traditionally. • Magnesium contents higher than 1 wt.% lead to the presence of non-apatitic phases. • Agglomerates with micron and sub-micron porosity were obtained after heat-treatment

  20. Evolution of phase composition at thermal decomposition of magnesium hydroxide

    International Nuclear Information System (INIS)

    Thermal decomposition of magnesium hydroxide, which was produced by direct and inverse precipitation, was investigated. There is thermal decomposition of part of brucite and formation of amorphous hydroxide MgO·(1-x)H2O in temperatures range of 60-200 oC. In temperatures range of 300-400 oC the thermal decomposition of brucite to crystal magnesia passes together with decomposition of amorphous hydroxide MgO·(1-x)H2O to amorphous oxide. The nano sized reactionary-active powder of mix of amorphous and crystal magnesia can be used for synthesis of magnesium-aluminium spinel, cordierite and other compounds at temperatures lower, than traditional.

  1. Treatment of coking wastewater by using manganese and magnesium ores

    International Nuclear Information System (INIS)

    This study investigated a wastewater treatment technique based on natural minerals. A two-step process using manganese (Mn) and magnesium (Mg) containing ores were tested to remove typical contaminants from coking wastewater. Under acidic conditions, a reactor packed with Mn ore demonstrated strong oxidizing capability and destroyed volatile phenols, chemical oxygen demand (COD), and sulfide from the coking wastewater. The effluent was further treated by using Mg ore to remove ammonium-nitrogen and phosphate in the form of magnesium ammonium phosphate (struvite) precipitates. When pH of the wastewater was adjusted to 1.2, the removal efficiencies for COD, volatile phenol and sulfide reached 70%, 99% and 100%, respectively. During the second step of precipitation, up to 94% of ammonium was removed from the aqueous phase, and precipitated in the form of struvite with phosphorus. The struvite crystals showed a needle-like structure. X-ray diffraction and transmission electron microscopy were used to characterize the crystallized products.

  2. Preliminary study of biodegradation of AZ31B magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    REN Yibin; HUANG Jingjing; ZHANG Bingchun; YANG Ke

    2007-01-01

    Magnesium alloys are potential to be developed as a new type of biodegradable implant material by use of their active corrosion behavior.Both in vitro and in vivo biodegradation properties of an AZ31B magnesium alloy were investigated in this work.The results showed that AZ31B alloy has a proper degradation rate and much lower hydrogen release in Hank's solution,with a degradation rate of about 0.3 mm/year and hydrogen release below 0.15mL/cm2.The animal implantation test showed that the AZ31B alloy could slowly biodegrade in femur of the rabbit and form calcium phosphate around the alloy sample,with the Ca/P ratio close to the natural bone.

  3. Urinary and plasma magnesium and risk of ischemic heart disease

    NARCIS (Netherlands)

    Joosten, Michel M.; Gansevoort, Ron T.; Mukamal, Kenneth J.; van der Harst, Pim; Geleijnse, Johanna M.; Feskens, Edith J. M.; Navis, Gerjan; Bakker, Stephan J. L.

    2013-01-01

    Background: Previous studies on dietary magnesium and risk of ischemic heart disease (IHD) have yielded inconsistent results, in part because of a lack of direct measures of actual magnesium uptake. Urinary excretion of magnesium, an indicator of dietary magnesium uptake, might provide more consiste

  4. Magnesium Therapy for Intractable Ventricular Tachyarrhythmias in Normomagnesemic Patients

    OpenAIRE

    Iseri, Lloyd T.; Chung, Peter; Tobis, Jonathan

    1983-01-01

    Intractable ventricular tachyarrhythmia associated with hypomagnesemia responds well to magnesium given intravenously. Two patients with recurrent ventricular tachycardia and ventricular fibrillation associated with normal serum magnesium levels and resistant to treatment with potassium chloride, lidocaine and bretylium tosylate responded dramatically to the administration of magnesium sulfate. A third patient in whom the serum magnesium level was unknown also showed dramatic response to magn...

  5. An investigation of the relationship between having recent knowledge in basic biology and student success in Anatomy and Physiology I

    Science.gov (United States)

    Taylor, Edward T.

    Allied Health Programs generally require that students complete coursework in Human Anatomy and Physiology I and II as part of their Pre-Allied Health curriculum. Human Anatomy and Physiology I generally has as a prerequisite some coursework in basic biology. Basic biology as a prerequisite should provide students with the foundation of knowledge in the basic biological principles and processes that will prepare them for the material presented in a Human Anatomy and Physiology I course and the Allied Health Program. The principle question that prompted this study was, Do students need coursework in basic biology to be successful in Anatomy and Physiology I? The purpose of this study was to determine if there was a difference in the exam average obtained in Biology 202, Human Anatomy and Physiology I, for those students who have had, within the previous three years, a foundation course in basic biology as compared to those students who have not, within the previous three years, had a foundation course in basic biology. The current study analyzed data obtained on 642 students who were enrolled in Biology 202, Anatomy and Physiology I, during the Fall semester of 2000 to the Spring semester of 2003 at Wor-Wic Community College. Statistical techniques including an ANOVA, Pearson Product Moment Correlation, and a Multiple Regression Analysis were conducted to reveal any relationships in the data. The dependent variable was the exam average obtained in the independent variables included the time period since the student had taken a basic biology course, sex, age, and college GPA. The results of the ANOVA indicated that there was no relationship between the exam average between current and non-current students, where alpha = 0.05 and p = 0.783. There was statistically significance for GPA, where p = 0 .000. There was also statistically significant interactions between last biology course and GPA, p = 0.05, last biology course, sex, and GPA, p = 0.002. The Pearson Product

  6. SON68 glass dissolution driven by magnesium silicate precipitation

    International Nuclear Information System (INIS)

    Experimental results are reported on the effect of magnesium silicate precipitation on the mechanisms and rate of borosilicate glass dissolution. Leaching experiments with SON68 glass, a borosilicate containing no Mg, were carried out in initially deionized water at 50 °C with a glass-surface-area-to-solution-volume ratio of 20,000 m−1. After 29 days of alteration the experimental conditions were modified by the addition of Mg to trigger the precipitation of Mg-silicate. Additional experiments were conducted to investigate the importance of other parameters such as pH or dissolved silica on the mechanisms of precipitation of Mg-silicates and their consequences on the glass dissolution rate. Mg-silicates precipitate immediately after Mg is added. The amount of altered glass increases with the quantity of added Mg, and is smaller when silicon is added in solution. A time lag is observed between the addition of magnesium and the resumption of glass alteration because silicon is first provided by partial dissolution of the previously formed alteration gel. It is shown that nucleation does not limit Mg-silicate precipitation. A pH above 8 is necessary for the phase to precipitate under the investigated experimental conditions. On the other hand the glass alteration kinetics limits the precipitation if the magnesium is supplied in solution at a non-limiting rate

  7. Fabrication of a Delaying Biodegradable Magnesium Alloy-Based Esophageal Stent via Coating Elastic Polymer

    Directory of Open Access Journals (Sweden)

    Tianwen Yuan

    2016-05-01

    Full Text Available Esophageal stent implantation can relieve esophageal stenosis and obstructions in benign esophageal strictures, and magnesium alloy stents are a good candidate because of biodegradation and biological safety. However, biodegradable esophageal stents show a poor corrosion resistance and a quick loss of mechanical support in vivo. In this study, we chose the elastic and biodegradable mixed polymer of Poly(ε-caprolactone (PCL and poly(trimethylene carbonate (PTMC as the coated membrane on magnesium alloy stents for fabricating a fully biodegradable esophageal stent, which showed an ability to delay the degradation time and maintain mechanical performance in the long term. After 48 repeated compressions, the mechanical testing demonstrated that the PCL-PTMC-coated magnesium stents possess good flexibility and elasticity, and could provide enough support against lesion compression when used in vivo. According to the in vitro degradation evaluation, the PCL-PTMC membrane coated on magnesium was a good material combination for biodegradable stents. During the in vivo evaluation, the proliferation of the smooth muscle cells showed no signs of cell toxicity. Histological examination revealed the inflammation scores at four weeks in the magnesium-(PCL-PTMC stent group were similar to those in the control group (p > 0.05. The α-smooth muscle actin layer in the media was thinner in the magnesium-(PCL-PTMC stent group than in the control group (p < 0.05. Both the epithelial and smooth muscle cell layers were significantly thinner in the magnesium-(PCL-PTMC stent group than in the control group. The stent insertion was feasible and provided reliable support for at least four weeks, without causing severe injury or collagen deposition. Thus, this stent provides a new stent for the treatment of benign esophageal stricture and a novel research path in the development of temporary stents in other cases of benign stricture.

  8. Monitoring Biodegradation of Magnesium Implants with Sensors

    Science.gov (United States)

    Zhao, Daoli; Wang, Tingting; Guo, Xuefei; Kuhlmann, Julia; Doepke, Amos; Dong, Zhongyun; Shanov, Vesselin N.; Heineman, William R.

    2016-04-01

    Magnesium and its alloys exhibit properties such as high strength, light weight, and in vivo corrosion that make them promising candidates for the development of biodegradable metallic implant materials for bone repair, stents and other medical applications. Sensors have been used to monitor the corrosion of magnesium and its alloys by measuring the concentrations of the following corrosion products: magnesium ions, hydroxyl ions and hydrogen gas. The corrosion characterization system with home-made capillary pH and Mg2+ microsensors has been developed for real-time detection of magnesium corrosion in vitro. A hydrogen gas sensor was used to monitor the corrosion of magnesium by measuring the concentration of the hydrogen gas reaction product in vivo. The high permeability of hydrogen through skin allows transdermal monitoring of the biodegradation of a magnesium alloy implanted beneath the skin by detecting hydrogen gas at the skin surface. The sensor was used to map hydrogen concentration in the vicinity of an implanted magnesium alloy.

  9. Magnesium and its alloys as degradable biomaterials: corrosion studies using potentiodynamic and EIS electrochemical techniques

    Directory of Open Access Journals (Sweden)

    Wolf Dieter Müller

    2007-03-01

    Full Text Available Magnesium is potentially useful for orthopaedic and cardiovascular applications. However, the corrosion rate of this metal is so high that its degradation occurs before the end of the healing process. In industrial media the behaviour of several magnesium alloys have been probed to be better than magnesium performance. However, the information related to their corrosion behaviour in biological media is insufficient. The aim of this work is to study the influence of the components of organic fluids on the corrosion behaviour of Mg and AZ31 and LAE442 alloys using potentiodynamic, potentiostatic and EIS techniques. Results showed localized attack in chloride containing media. The breakdown potential decreased when chloride concentration increased. The potential range of the passivation region was extended in the presence of albumin. EIS measurements showed that the corrosion behaviour of the AZ31 was very different from that of LAE442 alloy in chloride solutions.

  10. Formation of Ha-Containing Coating on AZ31 Magnesium Alloy by Micro-Arc Oxidation

    Science.gov (United States)

    Tang, Hui; Li, Deyu; Chen, Xiuping; Wu, Chao; Wang, Fuping

    2013-08-01

    Magnesium and its alloys are potential biodegradable implant materials due to their attractive biological properties. But the use of magnesium is still hampered by its poor corrosion resistance in physiological fluids. In this study, a HA-containing coating was fabricated by micro-arc oxidation (MAO). The active plasma species of micro-discharge was studied by optical emission spectroscopy (OES). The microstructure and composition were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion behavior and apatite-forming ability were studied by electrochemical tests and immersed samples in simulated body fluids (SBF). The results show that the microdischarge channel model is gas discharges and oxide layer discharges. The elements from the substrate and electrolyte take part in the formation of the coating. The MAO coating significantly improves the corrosion resistance of AZ31 magnesium alloy and enhances the apatite formation ability.

  11. Magnesium supplement in pregnancy-induced hypertension. A clinicopathological study

    DEFF Research Database (Denmark)

    Rudnicki, M; Junge, Jette; Frølich, A;

    1990-01-01

    as a double-blind randomized controlled study in which 11 women were allocated to magnesium and 7 to placebo treatment. The treatment comprised a 48-hour intravenous magnesium/placebo infusion followed by daily oral magnesium/placebo intake until one day after delivery. Magnesium supplement increased birth....... There was no significant difference when the magnesium group, the placebo group and the control group were compared separately. The present study suggests that magnesium supplement has a beneficial effect on fetal growth in pregnancy-induced hypertension. With regard to the light and electron microscopic changes we were...... unable to demonstrate any significant difference between the magnesium, placebo and control groups....

  12. An Evaluation of Two Different Methods of Assessing Independent Investigations in an Operational Pre-University Level Examination in Biology in England.

    Science.gov (United States)

    Brown, Chris

    1998-01-01

    Explored aspects of assessment of extended investigation ("project") practiced in the operational examinations of The University of Cambridge Local Examinations Syndicate (UCLES) for the perspective of construct validity. Samples of the 1993 (n=333) and 1996 (n=259) biology test results reveal two methods of assessing the project. (MAK)

  13. Preparation of biomimetic hydrophobic coatings on AZ91D magnesium alloy surface

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The hydrophobic coating has been a promising technology for improving surface performance. The surface performance of magnesium alloy has been limited in application. Furthermore, the hydrophobic of magnesium alloy is rarely investigated because magnesium alloy is an active metal alloy. In this paper, inspired by microstructure character of typical plant leaf surface such as lotus, the biomimetic hydrophobic coatings on AZ91D magnesium alloy surface were prepared by means of wet-chemical combining electroless. The samples were immersed into AgNO3 solution in wet-chemical method firstly. Then, biomimetic hydrophobic coatings were prepared by electroless after wet-method pretreatment. The microstructure was observed by SEM and the contact angles were measured by contact angle tester. The results indicated that the biomimetic hydrophobic coatings with uniform crystalline and dense structure could be obtained on AZ91D magnesium alloy surface. The results of contact angle revealed that the biomimetic nano-composite coatings were hydrophobic. The wet-chemical method treatment on the AZ91D magnesium alloy substrate provided a rough microstructure, thus improving adhesion of the coating and the substrate.

  14. In vitro corrosion and biocompatibility study of phytic acid modified WE43 magnesium alloy

    Science.gov (United States)

    Ye, C. H.; Zheng, Y. F.; Wang, S. Q.; Xi, T. F.; Li, Y. D.

    2012-02-01

    Phytic acid (PA) conversion coating on WE43 magnesium alloy was prepared by the method of immersion. The influences of phytic acid solution with different pH on the microstructure, properties of the conversion coating and the corrosion resistance were investigated by SEM, FTIR and potentiodynamic polarization method. Furthermore, the biocompatibility of different pH phytic acid solution modified WE43 magnesium alloys was evaluated by MTT and hemolysis test. The results show that PA can enhance the corrosion resistance of WE43 magnesium especially when the pH value of modified solution is 5 and the cytotoxicity of the PA coated WE43 magnesium alloy is much better than that of the bare WE43 magnesium alloy. Moreover, all the hemolysis rates of the PA coated WE43 Mg alloy were lower than 5%, indicating that the modified Mg alloy met the hemolysis standard of biomaterials. Therefore, PA coating is a good candidate to improve the biocompatibility of WE43 magnesium alloy.

  15. Effect of HCl pre-treatment on corrosion resistance of cerium-based conversion coatings on magnesium and magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Brunelli, Katya [Department of Mechanical Innovation and Management, University of Padua, Via Marzolo 9, 35131 Padua (Italy); Dabala, Manuele [Department of Mechanical Innovation and Management, University of Padua, Via Marzolo 9, 35131 Padua (Italy)]. E-mail: manuele.dabala@unipd.it; Calliari, Irene [Department of Mechanical Innovation and Management, University of Padua, Via Marzolo 9, 35131 Padua (Italy); Magrini, Maurizio [Department of Mechanical Innovation and Management, University of Padua, Via Marzolo 9, 35131 Padua (Italy)

    2005-04-01

    The corrosion protection afforded by a cerium conversion coating, formed by immersion in a solution containing rare earth salt and hydrogen peroxide, on pure magnesium and two magnesium alloys, AZ91 and AM50, has been studied. The effect of HCl pre-treatments on the morphology and on the corrosion resistance of the cerium conversion layer was investigated. A thicker and more homogeneous distribution of the conversion coating was obtained when the sample surface was pre-treated with acid. Higher amounts of cerium on the surface of the pre-treated samples were detected. The cerium conversion coating increased the corrosion resistance of the alloys because it ennobled the corrosion potential and decreased both the anodic and cathodic current. The acid pre-treatment further increased the corrosion resistance of the coated alloys. After five days of immersion in chloride environment the untreated samples showed localized corrosion while the chemical conversion coated samples appeared unaffected.

  16. Magnesium doping of boron nitride nanotubes

    Science.gov (United States)

    Legg, Robert; Jordan, Kevin

    2015-06-16

    A method to fabricate boron nitride nanotubes incorporating magnesium diboride in their structure. In a first embodiment, magnesium wire is introduced into a reaction feed bundle during a BNNT fabrication process. In a second embodiment, magnesium in powder form is mixed into a nitrogen gas flow during the BNNT fabrication process. MgB.sub.2 yarn may be used for superconducting applications and, in that capacity, has considerably less susceptibility to stress and has considerably better thermal conductivity than these conventional materials when compared to both conventional low and high temperature superconducting materials.

  17. (n, γ)-radiolysis of magnesium iodate

    International Nuclear Information System (INIS)

    The initial retention of thermal neutron irradiated magnesium iodate tetrahydrate was found to be 47% and increased to 54% for the dehydrated salt. The post irradiation isothermal annealing followed the characteristic pattern both in hydrated and dehydrated salts; the rate of increase in retention in the hydrated salt being faster than in the dehydrated form. At an annealing temperature of 453 K, 100% retention was achieved by the hydrated salt but the corresponding value for the dehydrated magnesium iodate was not higher than 88%. The role of water of crystallization in the retention studies of magnesium iodate is discussed. (author)

  18. On the hydrogenation mechanism in magnesium I

    DEFF Research Database (Denmark)

    Pedersen, A.S.; Kjøller, John; Larsen, Bent;

    1985-01-01

    The first time hydriding of spherical magnesium particles covered by a thin oxide layer and sieve-fractionated into narrow size distributions within the range 40–90 μm was followed by microgravimetry. The size distributions of the fractions were determined by semiautomatic image analysis. The hyd......The first time hydriding of spherical magnesium particles covered by a thin oxide layer and sieve-fractionated into narrow size distributions within the range 40–90 μm was followed by microgravimetry. The size distributions of the fractions were determined by semiautomatic image analysis...... generalizing results from the hydriding of magnesium powders....

  19. Biocorrosion rate and mechanism of metallic magnesium in model arterial environments

    Science.gov (United States)

    Bowen, Patrick K.

    A new paradigm in biomedical engineering calls for biologically active implants that are absorbed by the body over time. One popular application for this concept is in the engineering of endovascular stents that are delivered concurrently with balloon angioplasty. These devices enable the injured vessels to remain patent during healing, but are not needed for more than a few months after the procedure. Early studies of iron- and magnesium-based stents have concluded that magnesium is a potentially suitable base material for such a device; alloys can achieve acceptable mechanical properties and do not seem to harm the artery during degradation. Research done up to the onset of research contained in this dissertation, for the most part, failed to define realistic physiological corrosion mechanisms, and failed to correlate degradation rates between in vitro and in vivo environments. Six previously published works form the basis of this dissertation. The topics of these papers include (1) a method by which tensile testing may be applied to evaluate biomaterial degradation; (2) a suite of approaches that can be used to screen candidate absorbable magnesium biomaterials; (3) in vivo-in vitro environmental correlations based on mechanical behavior; (4) a similar correlation on the basis of penetration rate; (5) a mid-to-late stage physiological corrosion mechanism for magnesium in an arterial environment; and (6) the identification of corrosion products in degradable magnesium using transmission electron microscopy.

  20. Intestinal absorption of magnesium from food and supplements.

    OpenAIRE

    Fine, K D; Santa Ana, C A; Porter, J L; Fordtran, J S

    1991-01-01

    The purpose of this study was to measure magnesium absorption over the wide range of intakes to which the intestine may be exposed from food and/or magnesium-containing medications. Net magnesium absorption was measured in normal subjects after they ingested a standard meal supplemented with 0, 10, 20, 40, and 80 mEq of magnesium acetate. Although absorption increased with each increment in intake, fractional magnesium absorption fell progressively (from 65% at the lowest to 11% at the highes...

  1. The reference range of serum, plasma and erythrocyte magnesium

    Directory of Open Access Journals (Sweden)

    Suzanna Immanuel

    2006-12-01

    Full Text Available The interest in the clinical importance of serum magnesium level has just recently begun with the analysis and findings of abnormal magnesium level in cardiovascular, metabolic and neuromuscular disorder. Although the serum level does not reflect the body magnesium level, but currently, only serum magnesium determination is widely used. Erythrocyte magnesium is considered more sensitive than serum magnesium as it reflects intracellular magnesium status. According to NCCLS (National Committee for Clinical Laboratory Standards every laboratory is recommended to have its own reference range for the tests it performs, including magnesium determination. The reference range obtained is appropriate for the population and affected by the method and technique. This study aimed to find the reference range of serum and plasma magnesium and also intracellular magnesium i.e. erythrocyte magnesium by direct method, and compare the results of serum and plasma magnesium. Blood was taken from 114-blood donor from Unit Transfusi Darah Daerah (UTDD Budhyarto Palang Merah Indonesia (PMI DKI Jakarta, consisted of 57 male and 57 female, aged 17 – 65 years, clinically healthy according to PMI donor criteria. Blood was taken from blood set, collected into 4 ml vacuum tube without anticoagulant for serum magnesium determination and 3 ml vacuum tube with lithium heparin for determination of erythrocyte and plasma magnesium Determination of magnesium level was performed with clinical chemistry auto analyzer Hitachi 912 by Xylidil Blue method colorimetrically. This study showed no significant difference between serum and heparinized plasma extra cellular magnesium. The reference range for serum or plasma magnesium was 1.30 – 2.00 mEq/L and for erythrocyte magnesium was 4.46 - 7.10 mEq/L. (Med J Indones 2006; 15:229-35Keywords: Reference range, extracellular magnesium, intracellular magnesium

  2. Boron Clusters as Highly Stable Magnesium-Battery Electrolytes**

    OpenAIRE

    Carter, Tyler J; Mohtadi, Rana; Arthur, Timothy S; Mizuno, Fuminori; Zhang, Ruigang; Shirai, Soichi; Kampf, Jeff W.

    2014-01-01

    Boron clusters are proposed as a new concept for the design of magnesium-battery electrolytes that are magnesium-battery-compatible, highly stable, and noncorrosive. A novel carborane-based electrolyte incorporating an unprecedented magnesium-centered complex anion is reported and shown to perform well as a magnesium-battery electrolyte. This finding opens a new approach towards the design of electrolytes whose likelihood of meeting the challenging design targets for magnesium-battery electro...

  3. Regulation of magnesium balance: lessons learned from human genetic disease

    OpenAIRE

    de Baaij, Jeroen H. F.; Hoenderop, Joost G. J.; Bindels, René J. M.

    2012-01-01

    Magnesium (Mg2+) is the fourth most abundant cation in the body. Thus, magnesium homeostasis needs to be tightly regulated, and this is facilitated by intestinal absorption and renal excretion. Magnesium absorption is dependent on two concomitant pathways found in both in the intestine and the kidneys: passive paracellular transport via claudins facilitates bulk magnesium absorption, whereas active transcellular pathways mediate the fine-tuning of magnesium absorption. The identification of g...

  4. Development and validation of simple titrimetric method for the determination of magnesium content in esomeprazole magnesium

    Directory of Open Access Journals (Sweden)

    R N Haddadin

    2011-01-01

    Full Text Available A simple and inexpensive titrimetric method for the determination of magnesium ion in esomeprazole magnesium raw material was developed and validated according to International Conference on Harmonization guidelines and the United States Pharmacopoeia. The method depends on complex formation between EDTA and magnesium ion. The method was proven to be valid, equivalent and useful as an alternative method to the current pharmacopeial methods that are based on atomic absorption spectrometry.

  5. A multidisciplinary study on magnesium

    Directory of Open Access Journals (Sweden)

    Radić-Perić Jelena

    2012-01-01

    Full Text Available During plasma electrolytic oxidation of a magnesium alloy (96% Mg, 3% Al, 1% Zn we obtained a luminescence spectrum in the wave number range between 19 950 and 20 400 cm-1. The broad peak with clearly pronounced structure was assigned to the v’-v” = 0 sequence of the B 1Σ+ → X 1Σ+ electronic transition of MgO. Quantum-mechanical perturbative approach was applied to extract the form of the potential energy curves for the electronic states involved in the observed spectrum, from the positions of spectral bands. These potential curves, combined with the results of quantum-chemical calculations of the electric transition moment, were employed in subsequent variational calculations to obtain the Franck-Condon factors and transition moments for the vibrational transitions observed. Comparing the results of these calculations with the measured intensity distribution within the spectrum we derived relative population of the upper electronic state vibration levels. This enabled us to estimate the plasma temperature. Additionally, the temperature was determined by analysis of the recorded A 2Σ+ (v’ = 0 - X 2П (v” = 0 emission spectrum of OH. The composition of plasma containing magnesium, oxygen, and hydrogen under assumption of local thermal equilibrium was calculated in the temperature range up to 12 000 K and for pressures of 105, 106, 107, and 108 Pa, in order to explain the appearance of the observed spectral features and to contribute to elucidation of processes taking place during the electrolytic oxidation of Mg. [Projekat Ministarstva nauke Republike Srbije, br. 172040

  6. Biodegradable mesoporous calcium–magnesium silicate-polybutylene succinate scaffolds for osseous tissue engineering

    Directory of Open Access Journals (Sweden)

    Zhang X

    2015-10-01

    Full Text Available Xinxin Zhang,1,2,* Chi Zhang,3,* Wei Xu,1,* Biao Zhong,3 Feng Lin,3 Jian Zhang,3 Quanxiang Wang,4 Jiajin Ji,4 Jie Wei,4 Yang Zhang1 1TongRen Hospital, School of Medicine, Shanghai Jiao Tong University, 2Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 3Shanghai Sixth People’s Hospital, Shanghai Jiao Tong University, 4Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: The structural features of bone engineering scaffolds are expected to exhibit osteoinductive behavior and promote cell adhesion, proliferation, and differentiation. In the present study, we employed synthesized ordered mesoporous calcium–magnesium silicate (om-CMS and polybutylene succinate (PBSu to develop a novel scaffold with potential applications in osseous tissue engineering. The characteristics, in vitro bioactivity of om-CMS/PBSu scaffold, as well as the cellular responses of MC3T3-E1 cells to the composite were investigated. Our results showed that the om-CMS/PBSu scaffold possesses a large surface area and highly ordered channel pores, resulting in improved degradation and biocompatibility compared to the PBSu scaffold. Moreover, the om-CMS/PBSu scaffold exhibited significantly higher bioactivity and induced apatite formation on its surface after immersion in the simulated body fluid. In addition, the om-CMS/PBSu scaffold provided a high surface area for cell attachment and released Ca, Mg, and Si ions to stimulate osteoblast proliferation. The unique surface characteristics and higher biological efficacy of the om-CMS/PBSu scaffold suggest that it has great potential for being developed into a system that can be employed in osseous tissue engineering. Keywords: bone repair, polybutylene succinate, calcium–magnesium silicate, ordered mesoporous, proliferation

  7. Microstructure-modified biodegradable magnesium alloy for promoting cytocompatibility and wound healing in vitro.

    Science.gov (United States)

    Lin, Da-Jun; Hung, Fei-Yi; Yeh, Ming-Long; Lui, Truan-Sheng

    2015-10-01

    The microstructure of biomedical magnesium alloys has great influence on anti-corrosion performance and biocompatibility. In practical application and for the purpose of microstructure modification, heat treatments were chosen to provide widely varying microstructures. The aim of the present work was to investigate the influence of the microstructural parameters of an Al-free Mg-Zn-Zr alloy (ZK60), and the corresponding heat-treatment-modified microstructures on the resultant corrosion resistance and biological performance. Significant enhancement in corrosion resistance was obtained in Al-free Mg-Zn-Zr alloy (ZK60) through 400 °C solid-solution heat treatment. It was found that the optimal condition of solid-solution treatment homogenized the matrix and eliminated internal defects; after which, the problem of unfavorable corrosion behavior was improved. Further, it was also found that the Mg ion-release concentration from the modified ZK60 significantly induced the cellular activity of fibroblast cells, revealing in high viability value and migration ability. The experimental evidence suggests that this system can further accelerate wound healing. From the perspective of specific biomedical applications, this research result suggests that the heat treatment should be applied in order to improve the biological performance. PMID:26411444

  8. Development of Magnesium-Insertion Positive Electrode for Rechargeable Magnesium Batteries

    Institute of Scientific and Technical Information of China (English)

    Huatang YUAN; Lifang JIAO; Jiansheng CAO; Xiusheng LIU; Ming ZHAO; Yongmei WANG

    2004-01-01

    Magnesium-based rechargeable batteries might be an interesting future alternative to lithium-based batteries. It is so far well known that Mg2+ ion insertion into ion-transfer hosts proceeds slowly compared with Li+, so it is necessary to realize fast Mg2+ transport in the host in addition to other requirements as practical cathode materials for magnesium batteries. Positive electrode materials based on inorganic transition-metal oxides, sulfides, and borides are the only ones used up to now to insert magnesium ions. In this paper, the available results of research on materials suitable as possible, for secondary magnesium batteries, are reviewed.

  9. Report of biological investigations at the Los Medanos Waste Isolation Pilot Plant (WIPP) area of New Mexico during FY 1978

    Energy Technology Data Exchange (ETDEWEB)

    Best, T.L.; Neuhauser, S. (eds.)

    1980-03-01

    The US Department of Energy is considering the construction of a Waste Isolation Pilot Plant (WIPP) in Eddy County, NM. This location is approximately 40 km east of Carlsbad, NM. Biological studies during FY 1978 were concentrated within a 5-mi radius of drill hole ERDA 9. Additional study areas have been established at other sites in the vicinity, e.g., the Gnome site, the salt lakes and several stations along the Pecos River southward from Carlsbad, NM, to the dam at Red Bluff Reservoir in Texas. The precise locations of all study areas are presented and their biology discussed.

  10. A novel bench-scale column assay to investigate site-specific nitrification biokinetics in biological rapid sand filters

    DEFF Research Database (Denmark)

    Tatari, Karolina; Smets, Barth F.; Albrechtsen, Hans-Jørgen

    2013-01-01

    A bench-scale assay was developed to obtain site-specific nitrification biokinetic information from biological rapid sand filters employed in groundwater treatment. The experimental set-up uses granular material subsampled from a full-scale filter, packed in a column, and operated with controlled....../m3 packed sand/h could easily be determined at 7.5 g NH4+–N/m3 packed sand/h. This assay, with conditions reflecting full-scale observations, and where the biological activity is subject to minimal physical disturbance, provides a simple and fast, yet powerful tool to gain insight in nitrification...

  11. Report of biological investigations at the Los Medanos Waste Isolation Pilot Plant (WIPP) area of New Mexico during FY 1978

    International Nuclear Information System (INIS)

    The US Department of Energy is considering the construction of a Waste Isolation Pilot Plant (WIPP) in Eddy County, NM. This location is approximately 40 km east of Carlsbad, NM. Biological studies during FY 1978 were concentrated within a 5-mi radius of drill hole ERDA 9. Additional study areas have been established at other sites in the vicinity, e.g., the Gnome site, the salt lakes and several stations along the Pecos River southward from Carlsbad, NM, to the dam at Red Bluff Reservoir in Texas. The precise locations of all study areas are presented and their biology discussed

  12. The distribution of magnesium in developing rat incisor dentin

    International Nuclear Information System (INIS)

    Previous studies have shown that rat incisor dentin contains a considerable amount of magnesium that is distributed heterogeneously. The cementum-related dentin, especially its incisal portion, is richest in magnesium. It was the purpose of the present study to investigate the changes that occur in the magnesium content during dentin maturation. Cross-sections were prepared from rat incisors at the apical, middle, and incisal levels. By means of an electron microprobe, tracings were made of the Ca-, Mg-, and P- signal frequencies. Comparison of corresponding dentin layers within and between the cross-sections showed that the Mg/P molar ratio was always higher in the cementum-related dentin (CRD) than in the enamel-related dentin (ERD) and increased from the apex toward the incisal edge. Especially in the incisal cross-section, an increase in Mg/P was found from the older (peripheral) toward the younger (central) dentin layers. As the Mg/P ratio varied from 0.07 to 0.33, the Ca/P ratio was found to fluctuate from 1.48 to 1.15. The two ratios appeared to be highly correlated (r = -0.97; p less than 0.001), suggesting that Mg replaces Ca and is bound to phosphate

  13. Magnesium Sulphide as Anode Material for Lithium-Ion Batteries

    International Nuclear Information System (INIS)

    Highlights: • A single step preparation method of magnesium sulphide-carbon composite by mechanically milling the elemental mixture is reported. • The as-prepared MgS-carbon composite was investigated as an anode for lithium-ion batteries. • From XRD and electrochemical studies a reversible lithiation/delithiation mechanism of MgS is concluded. • The practicality of MgS-carbon composite anode in full cell using lithium nickel manganese cobalt oxide (LNMC) and lithium iron phosphate (LFP) as cathodes are evaluated. -- Abstract: Herein, we report magnesium sulphide (MgS) as an anode for lithium ion batteries. Magnesium sulphide-carbon composite is directly synthesized by mechanically milling the elemental mixture. A possible lithiation and delithiation mechanism for MgS is proposed based on electrochemical and ex-situ XRD studies. The electrochemical reaction of MgS with lithium results in the formation of Li2S and Mg, the as-formed Mg simultaneously reacts with lithium and forms LixMg alloy further contributing to the capacity. A stable reversible capacity of 530 mAh g−1 was achieved after 100 cycles within the voltage window of 0.001–2.5 V. The compatibility of MgS anode was tested in full cell using lithium nickel manganese cobalt oxide (LNMC) and lithium iron phosphate (LFP) as cathodes

  14. Processing magnesium alloys by severe plastic deformation

    Science.gov (United States)

    Figueiredo, Roberto B.; Aguilar, Maria Teresa P.; Cetlin, Paulo Roberto; Langdon, Terence G.

    2014-08-01

    The use of severe plastic deformation techniques for processing magnesium alloys has moved from the early difficulties of processing to a stage of tailoring the best properties of these materials. The present paper reviews processing, structure and mechanical properties characterization. It is shown that ultrafine-grained structures are obtained in magnesium alloys processed by multiple passes of Equal-Channel Angular Pressing at moderate temperatures. Ultrafine-grained structures are also obtained by room temperature processing by High- Pressure Torsion. The ultrafine-grained structures increase strength and introduce excellent superplastic capabilities in many magnesium alloys. Moreover, processing magnesium alloys by severe plastic deformation leads to the development of anisotropy in mechanical behavior.

  15. Magnesium and anabolic hormones in older men

    OpenAIRE

    Maggio, M.; Ceda, G.P.; F. Lauretani; Cattabiani, C.; Avantaggiato, E.; Morganti, S.; Ablondi, F.; Bandinelli, S.; Dominguez, L. J.; M. Barbagallo; Paolisso, G.; Semba, R D; Ferrucci, L.

    2011-01-01

    Optimal nutritional and hormonal statuses are determinants of successful ageing. The age associated decline in anabolic hormones such as testosterone and insulin-like growth factor 1 (IGF-1) is a strong predictor of metabolic syndrome, diabetes and mortality in older men. Studies have shown that magnesium intake affects the secretion of total IGF-1 and increase testosterone bioactivity. This observation suggests that magnesium can be a modulator of the anabolic/catabolic equilibrium disrupted...

  16. Importance of molecular cell biology investigations in human medicine in the story of the Hutchinson-Gilford progeria syndrome

    Czech Academy of Sciences Publication Activity Database

    Raška, Ivan

    2010-01-01

    Roč. 3, č. 3 (2010), s. 89-93. ISSN 1337-6853 Grant ostatní: GA MŠk(CZ) LC535 Institutional research plan: CEZ:AV0Z50110509 Keywords : laminopathies * Hutchinson-Gilford progeria syndrome * progerin Subject RIV: EA - Cell Biology

  17. Elements determination of clinical relevance in biological tissues Dmdmdx/J dystrophic mice strains investigated by NAA

    International Nuclear Information System (INIS)

    In this work the determination of chemistry elements in biological tissues (whole blood, bones and organs) of dystrophic mice, used as animal model of Duchenne Muscular Dystrophy (DMD), was performed using analytical nuclear technique. The aim of this work was to determine reference values of elements of clinical (Ca, Cl, K, Mg, Na) and nutritional (Br and S) relevance in whole blood, tibia, quadriceps and hearts from Dmdmdx/J (10 males and 10 females) dystrophic mice and C57BL/6J (10 males) control group mice, using Neutron Activation Analysis technique (NAA). To show in more details the alterations that this disease may cause in these biological tissues, correlations matrixes of the DMDmdx/J mouse strain were generated and compared with C57BL/6J control group. For this study 119 samples of biological tissue were irradiated in the IEA-R1 nuclear reactor at IPEN (Sao Paulo, Brazil). The concentrations of these elements in biological tissues of Dmdmdx/J and C57B/6J mice are the first indicative interval for reference values. Moreover, the alteration in some correlation coefficients data among the elements in the health status and in the diseased status indicates a connection between these elements in whole blood, tibia, quadriceps and heart. These results may help the researchers to evaluate the efficiency of new treatments and to compare the advantages of different treatment approaches before performing tests in patients with muscular dystrophy. (author)

  18. The Investigation and Comparison of Furfural Removal from Wastewater using Cyclic Biological Reactor (CBR and Fusarium Culmorum Granules

    Directory of Open Access Journals (Sweden)

    Mostafa Leili

    2013-09-01

    Conclusion: Under different operating conditions of biological systems, high removal efficiency of furfural was observed, but CBR in comparison with Fusarium culmorum granules reached the optimum and desired removal efficiency in shorter time. Therefore, these systems can be developed and replaced with chemical methods to treat furfural containing wastewater.

  19. An Investigation into Students' Difficulties in Numerical Problem Solving Questions in High School Biology Using a Numeracy Framework

    Science.gov (United States)

    Scott, Fraser J.

    2016-01-01

    The "mathematics problem" is a well-known source of difficulty for students attempting numerical problem solving questions in the context of science education. This paper illuminates this problem from a biology education perspective by invoking Hogan's numeracy framework. In doing so, this study has revealed that the contextualisation of…

  20. Biological Sex, Adherence to Traditional Gender Roles, and Attitudes toward Persons with Mental Illness: An Exploratory Investigation.

    Science.gov (United States)

    Hinkelman, Lisa; Granello, Darcy Haag

    2003-01-01

    Undergraduate students responded to the Community Attitudes toward the Mentally Ill (CAMI) questionnaire and the Hypergender Ideology Scale, which measures the degree to which they adhered to traditional gender roles. It was determined that strict gender-role adherence, rather than biological sex accounted for the variance in CAMI scores.…

  1. TRICHODERMA VIRIDE PERS. – EXPERIMENTAL MODEL FOR BIOLOGICAL AND BIOTECHNOLOGICAL INVESTIGATIONS OF MYCROMYCETA WITH IMPORTANCE IN OBTAINING PLANT PROTECTION BIOPRODUCTS

    Directory of Open Access Journals (Sweden)

    SESAN TATIANA EUGENIA

    2010-12-01

    Full Text Available The technological process for obtaining plant protection bioproducts contains 2 main phases: (i biomass biosynthesis of microorganisms in a culture medium, available for industrialization and (ii biomass conditioning of microorganism, the antagonistic micromycetes, respectively. For this type of activities it is essential to establish biological development parameters: (i the optimum composition of the liquid culture medium for development of the fungus under aerobiotic conditions and (ii the optimal parameters of biosynthesis in the studied medium. The biomass biosynthesis technology is discontinuous, of cascade type, and develops several phases: (1 preparing of the laboratory inoculum, (2 preparing of the fungal pure culture in Erlenmeyer bottles, (3 industrial (simulated multiplication in the aired and agitated liquid medium.This paper presents some experimental aspects referring to: 1 – Characterization of the biologically active T. viride isolates, establishing and verifying of their biological thresholds; 2 – Evaluation and experimental verifying of the mass multiplication ability of antagonistic T. viride fungi on the culture media in order to select the optimum industrial culture substrate (medium; 3 – Biochimical characterization of T. viride isolates by electrophoretic analysis of their protein profile; 4 – Evaluation of the T. viride biological activity of T. viride isolates against phytopathogenic fungi with high practical importance: Fusarium graminearum Schwabe (T. Gibberella zeae (Schwein. Petch, F. culmorum (W. G. Sm. Sacc., Pythium ultimum Trow, Botrytis cinerea Pers., Sclerotinia sclerotiorum (Lib. de Bary, Alternaria spp. [A. alternata (Fr. Keissl., Alternaria radicina Meier, Drechsler and E. D. Eddy (Stemphylium radicinum (Meier, Drechsler and E. D. Eddy Neerg.] etc.; 5 – Processing of technological scheme for obtaining plant protection preparates based on biologically active isolates of T. viride.

  2. Correlation of magnesium intake with metabolic parameters, depression and physical activity in elderly type 2 diabetes patients: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Huang Jui-Hua

    2012-06-01

    Full Text Available Abstract Background Type 2 diabetes mellitus is a major global public health problem in the worldwide and is increasing in aging populations. Magnesium intake may be one of the most important factors for diabetes prevention and management. Low magnesium intake may exacerbate metabolic abnormalities. In this study, the relationships of magnesium intake with metabolic parameters, depression and physical activity in elderly patients with type 2 diabetes were investigated. Methods This cross-sectional study involved 210 type 2 diabetes patients aged 65 years and above. Participants were interviewed to obtain information on lifestyle and 24-hour dietary recall. Assessment of depression was based on DSM-IV criteria. Clinical variables measured included anthropometric measurements, blood pressure, and biochemical determinations of blood and urine samples. Linear regression was applied to determine the relationships of magnesium intake with nutritional variables and metabolic parameters. Results Among all patients, 88.6% had magnesium intake which was less than the dietary reference intake, and 37.1% had hypomagnesaemia. Metabolic syndromes and depression were associated with lower magnesium intake (p  0.05. A positive relationship was found between magnesium intake and HDL-cholesterol (p = 0.005. Magnesium intake was inversely correlated with triglyceride, waist circumference, body fat percent and body mass index (p p for trend = 0005. Waist circumference, body fat percentage, and body mass index were significantly lower with increase quartile of magnesium intake (p for trend p for trend  Conclusions The majority of elderly type 2 diabetes who have low magnesium intake may compound this deficiency with metabolic abnormalities and depression. Future studies should determine the effects of increased magnesium intake or magnesium supplementation on metabolic control and depression in elderly people with type 2 diabetes.

  3. Effects of calcium magnesium acetate on the combustion of Coal-Water Slurry

    Energy Technology Data Exchange (ETDEWEB)

    Levendis, Y.A.

    1990-01-01

    The general objective of the project is to investigate the combustion behavior of single and multiple Coal-Water Slurry particles burning at high temperature environments. Both uncatalyzed as well as catalyzed CWS drops with Calcium Magnesium Acetate (CMA) catalyst will be investigated. Emphasis will also be given in the effects of CMA on the sulfur capture during combustion.

  4. Association of Magnesium Intake with High Blood Pressure in Korean Adults: Korea National Health and Nutrition Examination Survey 2007–2009

    Science.gov (United States)

    Choi, Mi-Kyeong; Bae, Yun Jung

    2015-01-01

    Background Magnesium is known to lower the risk of cardiovascular disease. However, studies on its relationship with hypertension, a single and common cause of various chronic diseases, are limited and their findings are not consistent. The purpose of the present study is to identify the relationship between magnesium intake and high blood pressure (HBP) risk in Koreans. Methods This research is a cross-sectional study based on the 2007~2009 Korean National Health and Nutritional Examination Survey data. This study investigated 11,685 adults aged over 20 to examine their general characteristics, anthropometry and blood pressure. Daily magnesium intake was analyzed using the 24-hour dietary recall method. To calculate the odds ratio (OR) of HBP risk (130/85 mmHg or over) according to the quartile of magnesium intake (mg/1000kcal) together with its 95% confidence interval (CI), multivariable logistic regression analysis was performed. Results No significant association between dietary magnesium intake and the risk of HBP was found. In obese women, particularly, after adjusting relevant factors, the adjusted odds ratio of HBP prevalence in the highest magnesium intake quartile was 0.40 compared with the lowest magnesium intake quartile (95% CI = 0.25~0.63, P for trend = 0.0014). Women, especially obese women, were found to have a negative relationship of magnesium intake with HBP. Conclusions The present results indicate that sufficient magnesium intake could be useful in decreasing the high blood pressure risk of obese women. PMID:26075385

  5. Fatigue Properties of Cast Magnesium Wheels

    Science.gov (United States)

    Li, Zhenming; Luo, Alan A.; Wang, Qigui; Peng, Liming; Zhang, Peng

    2016-05-01

    This paper investigates the fatigue properties and deformation behavior of a newly developed Mg-2.96Nd-0.21Zn-0.39Zr magnesium alloy wheel in both as-cast and T6 conditions. Compared with the as-cast alloy, the T6-treated alloy shows a significant increase in fatigue strength and cyclic stress amplitude. This is believed to be attributed to the change of defect type from porosity to oxides and the increased matrix strength in the T6 (peak-aged) condition. For the as-cast alloy wheel, fatigue failure mainly originated from the cast defects including porosity, oxide film, and inclusion at or near the sample surface. In the T6-treated alloy, however, oxides and inclusions or slip bands initiate the fatigue cracks. Solution treatment appears to reduce or eliminate the shrinkage porosity because of grain growth and dissolution of as-cast eutectic phases in the grain boundaries. The cyclic stress amplitude of the as-cast alloy increases with increasing the number of cycles, while the T6-treated alloy shows cyclic softening after the stress reaches a maximum value. The Coffin-Manson law and Basquin equation can be used to evaluate the life of low cycle fatigue. The developed long crack model and multi-scale fatigue (MSF) models can be used to predict high-cycle fatigue life of the Mg-2.96Nd-0.21Zn-0.39Zr alloys with or without casting defects.

  6. Silane coatings doped with corrosion inhibitors for protection of plasma-anodized magnesium and magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Darwich, S.; Lampke, T.; Alisch, G.; Dietrich, D. [Chemnitz Univ. of Technology (Germany). Inst. of Materials Science and Engineering

    2010-07-01

    Magnesium, with or without an additionally-formed oxide layer, shows enhanced corrosion resistance after immersion to form a silane coating. In the case of plasma anodised magnesium, pores similar to those occurring in anodised aluminium, are found. These pores can be impregnated with silane, thus providing increased corrosion resistance. (orig.)

  7. Building gene co-expression networks using transcriptomics data for systems biology investigations: Comparison of methods using microarray data

    OpenAIRE

    Kadarmideen, Haja N; Watson-Haigh, Nathan S

    2012-01-01

    Gene co-expression networks (GCN), built using high-throughput gene expression data are fundamental aspects of systems biology. The main aims of this study were to compare two popular approaches to building and analysing GCN. We use real ovine microarray transcriptomics datasets representing four different treatments with Metyrapone, an inhibitor of cortisol biosynthesis. We conducted several microarray quality control checks before applying GCN methods to filtered datasets. Then we compared ...

  8. Investigations in space-related molecular biology. [cryo-electron microscopic and diffraction studies on terrestrial and extraterrestrial specimens

    Science.gov (United States)

    Fernandez-Moran, H.; Pritzker, A. N.

    1974-01-01

    Improved instrumentation and preparation techniques for high resolution, high voltage cryo-electron microscopic and diffraction studies on terrestrial and extraterrestrial specimens are reported. Computer correlated ultrastructural and biochemical work on hydrated and dried cell membranes and related biological systems provided information on membrane organization, ice crystal formation and ordered water, RNA virus linked to cancer, lunar rock samples, and organometallic superconducting compounds. Apollo 11, 12, 14, and 15 specimens were analyzed

  9. Streamlined Total Synthesis of Uncialamycin and Its Application to the Synthesis of Designed Analogues for Biological Investigations.

    Science.gov (United States)

    Nicolaou, K C; Wang, Yanping; Lu, Min; Mandal, Debashis; Pattanayak, Manas R; Yu, Ruocheng; Shah, Akshay A; Chen, Jason S; Zhang, Hongjun; Crawford, James J; Pasunoori, Laxman; Poudel, Yam B; Chowdari, Naidu S; Pan, Chin; Nazeer, Ayesha; Gangwar, Sanjeev; Vite, Gregory; Pitsinos, Emmanuel N

    2016-07-01

    From the enediyne class of antitumor antibiotics, uncialamycin is among the rarest and most potent, yet one of the structurally simpler, making it attractive for chemical synthesis and potential applications in biology and medicine. In this article we describe a streamlined and practical enantioselective total synthesis of uncialamycin that is amenable to the synthesis of novel analogues and renders the natural product readily available for biological and drug development studies. Starting from hydroxy- or methoxyisatin, the synthesis features a Noyori enantioselective reduction, a Yamaguchi acetylide-pyridinium coupling, a stereoselective acetylide-aldehyde cyclization, and a newly developed annulation reaction that allows efficient coupling of a cyanophthalide and a p-methoxy semiquinone aminal to forge the anthraquinone moiety of the molecule. Overall, the developed streamlined synthesis proceeds in 22 linear steps (14 chromatographic separations) and 11% overall yield. The developed synthetic strategies and technologies were applied to the synthesis of a series of designed uncialamycin analogues equipped with suitable functional groups for conjugation to antibodies and other delivery systems. Biological evaluation of a select number of these analogues led to the identification of compounds with low picomolar potencies against certain cancer cell lines. These compounds and others like them may serve as powerful payloads for the development of antibody drug conjugates (ADCs) intended for personalized targeted cancer therapy. PMID:27266267

  10. Microstructure of AE44 magnesium alloy before and after hot-chamber die casting

    Directory of Open Access Journals (Sweden)

    A. Kiełbus

    2007-01-01

    Full Text Available Purpose: AE44 magnesium alloy allows attractive high temperature mechanical properties, as well as diecastabilityand good corrosion resistance. It contains magnesium, aluminum, cerium and lanthanum. Typically,it is used in automotive industry for structural components working at elevated temperature (150÷175°C. Theaim of this paper is to present the results of investigations on the microstructure of the AE44 magnesium alloybefore and after hot chamber die casting.Design/methodology/approach: Die casting was carried out on 280 tone locking force hot-chamber die castingmachine. For the microstructure observation, a Olympus GX+70 metallographic microscope and a HITACHIS-3400N scanning electron microscope with a Thermo Noran EDS spectrometer equipped with SYSTEM SIXwere used.Findings: Based on the investigation carried out it was found that the AE44 magnesium alloy before diecasting is characterized by α-Mg solid solution with globular, lamellar and acicular precipitations of Al11RE3and Al3RE phases. Moreover, there was found globular Mn-rich phase existence (probably Al8CeMn4 phase.After hot-chamber die casting the microstructure of AE44 alloys consist of equiaxed dendrites of α-Mg withprecipitates of Al11RE3 and probably Al2RE phase.Research limitations/implications: Future researches should contain investigations of the influence of the hotchamber die casting process parameters on the microstructure and mechanical properties of AE44 magnesiumalloy.Practical implications: AE44 magnesium alloy can be cast with cold- and hot-chamber die casting machine.Results of investigation may be useful for preparing die casting technology of this alloy.Originality/value: The results of the researches make up a basis for the investigations of new magnesium alloyscontaining rare earth elements for hot chamber die casting designed to service in elevated temperature.

  11. A review: Hot topics on magnesium technology in China

    Institute of Scientific and Technical Information of China (English)

    Zhen-hua CHEN; Ji-hua CHEN

    2008-01-01

    Magnesium alloys have wide applications in automobiles, aerospace and so on due to many advan-tages, while a number of undesirable properties including poor corrosion resistance, inferior creep resistance and bad plastic processing ability have hindered their applica-tions. Creep-resistant magnesium alloy design, plastic processing of magnesium alloys and rapid solidification processing of magnesium alloys have become the hot topics in magnesium technology. Other than these, surface modification as well as laser beam welding are also involved. The research progress and development in mag-nesium technology in China are reviewed in the paper.

  12. Magnesium and type 2 diabetes

    Institute of Scientific and Technical Information of China (English)

    Mario; Barbagallo; Ligia; J; Dominguez

    2015-01-01

    Type 2 diabetes is frequently associated with both extracellular and intracellular magnesium(Mg) deficits. A chronic latent Mg deficit or an overt clinical hypomagnesemia is common in patients with type 2 diabetes, especially in those with poorly controlled glycemic profiles. Insulinand glucose are important regulators of Mg metabolism. Intracellular Mg plays a key role in regulating insulin action, insulin-mediated-glucose-uptake and vascular tone. Reduced intracellular Mg concentrations result in a defective tyrosine-kinase activity, postreceptorial impairment in insulin action and worsening of insulin resistance in diabetic patients. A low Mg intake and an increased Mg urinary loss appear the most important mechanisms that may favor Mg depletion in patients with type 2 diabetes. Low dietary Mg intake has been related to the development of type 2 diabetes and metabolic syndrome. Benefits of Mg supplementation on metabolic profiles in diabetic patients have been found in most, but not all clinical studies and larger prospective studies are needed to support the potential role of dietary Mg supplementation as a possible public health strategy in diabetes risk. The aim of this review is to revise current evidence on the mechanisms of Mg deficiency in diabetes and on the possible role of Mg supplementation in the prevention and management of the disease.

  13. Hole centres in magnesium oxide

    International Nuclear Information System (INIS)

    When magnesium oxide crystals are exposed to ionizing radiation the electron-loss (hole) centres are normally identified as O·- ions. In this paper, I examine the EPR evidence for this, and compare the data with those for the hole centres in alkali- halides (VK centres). The latter are clearly σ* radical anions, such as F.-F-.The analogous centre in MgO is O.-O3-, which does not seem to have been considered. The results compare well, suggesting that the O·- centres are really O.-O3- radicals. In particular, the 17O data for the oxygen centre and the 19F data for F2·- give similar estimates of the 2s and 2p character of the orbitals on oxygen and fluorine, suggesting that the spin-density on oxygen is ca. 50%. The exception is the direction of the principal axes of these centres, which are quite different from each other. It is suggested that the primary hole-centres in MgO migrate by electron transfer to neighbouring cation vacancies where they are stable, and that at these sites the (1, 0, 0) directions are most favourable for σ- bonding

  14. Correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys

    International Nuclear Information System (INIS)

    X-ray photoelectron spectroscopy (XPS) was used in order to investigate the correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys exposed to 98% relative humidity at 50 deg. C. Commercially pure magnesium, used as the reference material, revealed MgO, Mg(OH)2 and tracers of magnesium carbonate in the air-formed film. For the AZ80 and AZ91D alloys, the amount of magnesium carbonate formed on the surface reached similar values to those of MgO and Mg(OH)2. A linear relation between the amount of magnesium carbonate formed on the surface and the subsequent corrosion behaviour in the humid environment was found. The AZ80 alloy revealed the highest amount of magnesium carbonate in the air-formed film and the highest atmospheric corrosion resistance, even higher than the AZ91D alloy, indicating that aluminium distribution in the alloy microstructure influenced the amount of magnesium carbonate formed.

  15. Correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Feliu, S. [Centro Nacional de Investigaciones Metalurgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Pardo, A. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040 Madrid (Spain)], E-mail: anpardo@quim.ucm.es; Merino, M.C. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040 Madrid (Spain); Coy, A.E.; Viejo, F.; Arrabal, R. [Corrosion and Protection Centre, School of Materials, University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD (United Kingdom)

    2009-01-15

    X-ray photoelectron spectroscopy (XPS) was used in order to investigate the correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys exposed to 98% relative humidity at 50 deg. C. Commercially pure magnesium, used as the reference material, revealed MgO, Mg(OH){sub 2} and tracers of magnesium carbonate in the air-formed film. For the AZ80 and AZ91D alloys, the amount of magnesium carbonate formed on the surface reached similar values to those of MgO and Mg(OH){sub 2}. A linear relation between the amount of magnesium carbonate formed on the surface and the subsequent corrosion behaviour in the humid environment was found. The AZ80 alloy revealed the highest amount of magnesium carbonate in the air-formed film and the highest atmospheric corrosion resistance, even higher than the AZ91D alloy, indicating that aluminium distribution in the alloy microstructure influenced the amount of magnesium carbonate formed.

  16. Correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys

    Science.gov (United States)

    Feliu, S., Jr.; Pardo, A.; Merino, M. C.; Coy, A. E.; Viejo, F.; Arrabal, R.

    2009-01-01

    X-ray photoelectron spectroscopy (XPS) was used in order to investigate the correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys exposed to 98% relative humidity at 50 °C. Commercially pure magnesium, used as the reference material, revealed MgO, Mg(OH) 2 and tracers of magnesium carbonate in the air-formed film. For the AZ80 and AZ91D alloys, the amount of magnesium carbonate formed on the surface reached similar values to those of MgO and Mg(OH) 2. A linear relation between the amount of magnesium carbonate formed on the surface and the subsequent corrosion behaviour in the humid environment was found. The AZ80 alloy revealed the highest amount of magnesium carbonate in the air-formed film and the highest atmospheric corrosion resistance, even higher than the AZ91D alloy, indicating that aluminium distribution in the alloy microstructure influenced the amount of magnesium carbonate formed.

  17. Studies on influence of zinc immersion and fluoride on nickel electroplating on magnesium alloy AZ91D

    International Nuclear Information System (INIS)

    The effect of zinc immersion and the role of fluoride in nickel plating bath were mainly investigated in nickel electroplating on magnesium alloy AZ91D. The state of zinc immersion, the composition of zinc film and the role of fluoride in nickel plating bath were explored from the curves of open circuit potential (OCP) and potentiodynamic polarization, the images of scanning electron microscopy (SEM) and the patterns of energy dispersive X-ray (EDX). Results show that the optimum zinc film mixing small amount of Mg(OH)2 and MgF2 is obtained by zinc immersion for 30-90 s. The corrosion potential of magnesium alloy substrate attached zinc film will be increased in nickel plating bath and the quantity of MgF2 sandwiched between magnesium alloy substrate and nickel coating will be reduced, which contributed to produce nickel coating with good performance. Fluoride in nickel plating bath serves as an activator of nickel anodic dissolution and corrosion inhibitor of magnesium alloy substrate. 1.0-1.5 mol dm-3 of F- is the optimum concentration range for dissolving nickel anode and protecting magnesium alloy substrate from over-corrosion in nickel plating bath. The nickel coating with good adhesion and high corrosion resistance on magnesium alloy AZ91D is obtained by the developed process of nickel electroplating. This nickel layer can be used as the rendering coating for further plating on magnesium alloys.

  18. Coating Prospects in Corrosion Prevention of Aluminized Steel and Its Coupling with Magnesium

    Science.gov (United States)

    Sun, Fuyan

    In this study, a plasma electrolytic oxidation (PEO) process was used to form oxide coating on aluminized steel, heated aluminized steel and magnesium. A potentiodynamic polarization corrosion test was employed to investigate the general corrosion properties. Galvanic corrosion of steel samples and magnesium samples was studied by zero resistance ammeter (ZRA) tests and boiling tests. Scanning electron microscopy (SEM) and EDS were used to investigate the coating microstructure and the coating/substrate interface. In general, the PEO coatings on all three substrate can help prevent general corrosion. 6-min coated magnesium with unipolar current mode performs best in most galvanic couplings for preventing both general corrosion and galvanic corrosion. Factors which could influence galvanic corrosion behaviors of tested samples were discussed based on area ratios of anode/cathode and cell potential driving force during the ZRA corrosion tests and boiling tests.

  19. Effect of twin boundary spacing on deformation behavior of nanotwinned magnesium

    International Nuclear Information System (INIS)

    The effect of twin spacing and temperature on the deformation behavior of nanotwinned magnesium is investigated using molecular dynamics simulation. The results indicate that there is a pronounced shift in the mechanical behavior of nanotwinned magnesium when twin spacing is smaller than 2.9 nm, and that the yield strength decreases with increasing temperature. The results show that at relatively high temperatures, a strength softening can be observed when twin spacing is larger than 7.8 nm. This study demonstrates that the yield strength is associated with the dislocation storage ability of nanotwinned magnesium and the repulsive force between twin boundaries and dislocations. -- Highlights: ► The dislocation nucleation and motion is a major deformation mode. ► The Young's modulus decreases with decreasing grain size. ► The deformation behavior at three different temperatures is investigated.

  20. Corrosion studies of A216 grade WCA steel in hydrothermal magnesium-containing brines

    International Nuclear Information System (INIS)

    The US Department of Energy's Salt Repository Project (SRP) is investigating the general corrosion resistance of cast mild steel as a candidate material for waste package containers. Evaluation of this material is being performed at the Pacific Northwest Laboratory in environments simulating expected repository conditions. General corrosion studies of mild steel (ASTM A216 grade WCA) in the as-cast and normalized conditions were conducted in hydrothermal halite-saturated (saturated at ambient temperature) brine environments simulating a ''dissolution'' and an ''inclusion'' brine. Corrosion tests were also performed in brines similar to the inclusion brine but containing magnesium concentrations ranging from 1000 to 30,000 ppM to investigate the effect of magnesium on the corrosion behavior. Corrosion rates of the cast mild steel were found to increase with increasing temperature and with increasing magnesium concentration. Some possible mechanisms that explain the observed behavior are presented. 8 refs., 7 figs., 2 tabs