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Sample records for biology investigating magnesium

  1. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    Directory of Open Access Journals (Sweden)

    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. Magnesium

    Science.gov (United States)

    ... by limiting the amount lost in urine. Low magnesium intakes for a long period of time, however, can ... is important for healthy bones. People with higher intakes of magnesium have a higher bone mineral density, which is ...

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

    Directory of Open Access Journals (Sweden)

    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.

  6. Investigations of microstructure and dislocations of cast magnesium alloys

    Directory of Open Access Journals (Sweden)

    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

  7. 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...

  8. Magnesium

    Science.gov (United States)

    Bechtel, H.; Bulian, W.; Bungardt, K.; Gürs, K.; Gürs, U.; Helling, W.; Kyri, H.; Laue, H. J.; Mahler, W.; Matting, A.; Meyer, F. R.; Mialki, W.; Ritter, F.; Ruge, J.; Saur, G.; Simon, W.; Strnat, K.; Weber, R.; Weigand, H. H.; Weik, H.; Ziesler, H.; Borchers, Heinz; Schmidt, Ernst

    Magnesium wird überwiegend durch Schmelzflußelektrolyse hergestellt. Das dabei anfallende Reinmagnesium hat einen Mg-Gehalt von etwa 99,9%. Hauptbeimengung ist das Eisen; Silizium und Aluminium sind nur in Spuren vorhanden. Der Anwendungsumfang des Reinmagnesiums ist gering; dagegen werden Magnesiumlegierungen zunehmend, insbesondere für den Druckguß verwendet. Neben den bis etwa zum Jahre 1950 allein gebräuchlichen Mg-Mn-, Mg-Al- und Mg-Al-Zn-Legierungen werden heute mehr und mehr die besonders warmfesten Legierungen mit Zusätzen von Zirkon, Thorium und Seltenen Erden hergestellt (siehe dazu auch Abschnitt Seltene Erden). Als Umhüllungsmaterial für Uranstäbe dient die Legierung Magnox A 12, die nach [H 3] neben 1 % Al noch geringe Mengen an Ca und Ba enthält. In den in Deutschland üblichen Kurzzeichen (DIN 1729) werden die chemischen Symbole und der ungefähre Gehalt der wichtigsten Legierungselemente angegeben. Gußlegierungen werden zusätzlich durch ein G (Sandguß oder Kokillenguß) oder ein D (Druckguß) gekennzeichnet (siehe Tab. 5).

  9. 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

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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 ...

  15. 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.

  16. 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

  17. 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…

  18. 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.

  19. 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)

  20. 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

  1. 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.

  2. 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}.

  3. 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.

  4. 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.

  5. 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.

  6. 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 ...

  7. 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

  8. Investigation of a novel passivation technique for gas atomized magnesium powders

    Science.gov (United States)

    Steinmetz, Andrew Douglas

    Gas atomized magnesium powders are critical for the production of a wide variety of flares, tracer projectiles, and other munitions for the United States military, along with a growing number of applications in both alloying and powder metallurgy. Gas atomization of magnesium is performed by numerous companies worldwide, but represents a single point failure within the United States as there is only one domestic producer. These powders are pyrophoric and must be handled carefully and kept dry at all times. Recent studies have explored the ability of certain fluorine containing cover gases to protect molten magnesium in casting operations from excessive vaporization and burning by modifying the native oxide (MgO) through interaction with these gas atmospheres. The present study sought to adapt this melt protection strategy for use as an in-situ passivation technique that could be employed to form a protective reaction film during gas atomization of magnesium powders. This fluorinated oxide shell was intended to provide superior coverage and adherence to the underlying metal, which may improve the ability of powders to resist ignition at elevated temperatures and during powder handling. Two candidate gases were tested in this research, SF6 and NF3, and reaction films of both were produced on miniature melt samples in a controlled environment and characterized using auger electron spectroscopy and x-ray photoelectron spectroscopy. Ultimately, SF6 was chosen to conduct a small scale magnesium atomization experiment for verification of the fluorination reaction and to experimentally test the ignition temperature of these coated particles compared to other magnesium powders available today. This novel passivation technique was found to be far superior to magnesium's native oxide at resisting ignition and, thus, to reduce the hazard associated with handling and transport of magnesium powders for defense applications. If fully commercialized, this passivation method also

  9. 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.

  10. 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.

  11. 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.

  12. 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...... 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...

  13. 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 ...

  14. 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...

  15. 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

  16. 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....

  17. 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...

  18. Total synthesis and biological investigation of (-)-promysalin.

    Science.gov (United States)

    Steele, Andrew D; Knouse, Kyle W; Keohane, Colleen E; Wuest, William M

    2015-06-17

    Compounds that specifically target pathogenic bacteria are greatly needed, and identifying the method by which they act would provide new avenues of treatment. Herein we report the concise, high-yielding total synthesis (eight steps, 35% yield) of promysalin, a natural product that displays antivirulence phenotypes against pathogenic bacteria. Guided by bioinformatics, four diastereomers were synthesized, and the relative and absolute stereochemistries were confirmed by spectral and biological analysis. Finally, we show for the first time that promysalin displays two antivirulence phenotypes: the dispersion of mature biofilms and the inhibition of pyoverdine production, hinting at a unique pathogenic-specific mechanism of action.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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 ...

  4. Some investigations on the pitting attack of magnesium and its alloys; Contribution a l'etude de la corrosion par piqures du magnesium et de ses alliages

    Energy Technology Data Exchange (ETDEWEB)

    Blanchet, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-03-01

    The pitting attack of magnesium and its alloys has been studied by means of potentio-kinetic polarisation curves; the following parameters have been considered: structural state and composition of the metal, chloride concentration and pH of the medium. The electrochemical data obtained demonstrate that when pH = 12, a localized corrosion might appear as soon as a 10{sup -3} M NaCl concentration is reached; on the other hand, when pH = 13, a much higher concentration (five times) has no effect. In the same conditions, the coupling of magnesium with various noble materials (graphite, platinum, 18/10 stainless steel) also dramatically increases its susceptibility to pitting, but only when chloride ions are present in the solution. Usual corrosion tests have confirmed these electrochemical results. A micrographic study of the pits has shown that their morphology is connected with the metallurgical state of the specimens. (author) [French] La corrosion par piqures du magnesium est etudiee a l'aide des courbes de polarisation potentiocinetiques en fonction des parametres suivants etat structural et composition du metal, concentration en chlorure et pH de la solution. De ces mesures electrochimiques on deduit qu'a pH 12, des la concentration 10{sup -3} M en NaCl, il existe un risque de corrosion localisee, tandis qu'a pH 13 une concentration cinq fois plus forte doit etre sans effet. Dans les memes conditions on montre que le couplage du magnesium avec differents elements nobles (graphite, platine, acier inoxydable 18/10) accroit fortement sa susceptibilite a l'attaque par piqures, excepte dans les solutions exemptes d'ions chlorures. Des essais classiques de corrosion dans les differentes solutions envisagees precedemment confirment les resultats de cette etude electrochimique. L'examen micrographique des piqures montre que leur morphologie est liee a l'etat metallurgique des echantillons. (auteur)

  5. 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

  6. 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.

  7. 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.

  8. Ab initio investigation of the electronic and geometric structure of magnesium diboride, MgB2.

    Science.gov (United States)

    Tzeli, Demeter; Mavridis, Aristides

    2005-12-01

    Employing multireference variational (MRCI) and coupled cluster (CC) methods combined with quadruple-zeta quality correlation-consistent basis set, we have studied 36 states of the magnesium diboride (MgB(2)) molecule as well as 17 states of the experimentally unknown diatomic MgB. For all states of MgB(2), we report geometries, atomization energies, and dipole moments, while for the first 5 states, potential energy profiles have been also constructed. The ground state is formally of (1)A(1) V-shaped symmetry with an atomization energy of 108.1(109) kcal/mol at the MRCI(MRCI + Davidson correction) level. The first excited state ((3)B(1)) is less than 1 kcal/mol above the X(1)A(1) state, with the next state of linear Mg-B-B geometry (b(3)Sigma(-)) located 10 kcal/mol higher. In all states, bent or linear, the bonding is complicated and unconventional because of the extraordinary bonding agility of the boron atom(s).

  9. 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.

  10. 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.

  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. Laboratory investigations in cell biology. Second edition

    Energy Technology Data Exchange (ETDEWEB)

    Bregman, A.A.

    1987-01-01

    This text contains 18 lab projects that explore the structural, biochemical, and physiological nature of eukaryotic cells. Topics are largely traditional, however, several investigations employ new methodologies. Offers extended coverage of biochemistry. Materials have been selected for availability and ease of handling: e.g. Project 4 - extraction of DNA and RNA done with calf liver, Project 9 - succinate dehydrogenase activity studied in mitochondria isolated from cauliflower. There is more procedural detail than found in most lab manuals, negating the need for constant instructional details. And a variety of methodologies is introduced, such as Cytochemistry, Spectrophotometry, Electrophoresis, Cell Fractionation, silver staining of active sites of RNA transcription, and many more. Pages are perforated for collecting and grading.

  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. 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.

  15. 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

  16. 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...

  17. Dietary intake of iron, heme-iron and magnesium and pancreatic cancer risk in the European prospective investigation into cancer and nutrition cohort.

    Science.gov (United States)

    Molina-Montes, Esther; Wark, Petra A; Sánchez, María-José; Norat, Teresa; Jakszyn, Paula; Luján-Barroso, Leila; Michaud, Dominique S; Crowe, Francesca; Allen, Naomi; Khaw, Kay-Tee; Wareham, Nicholas; Trichopoulou, Antonia; Adarakis, George; Katarachia, Helen; Skeie, Guri; Henningsen, Maria; Broderstad, Ann Ragnhild; Berrino, Franco; Tumino, Rosario; Palli, Domenico; Mattiello, Amalia; Vineis, Paolo; Amiano, Pilar; Barricarte, Aurelio; Huerta, José-María; Duell, Eric J; Quirós, José-Ramón; Ye, Weimin; Sund, Malin; Lindkvist, Björn; Johansen, Dorthe; Overvad, Kim; Tjønneland, Anne; Roswall, Nina; Li, Kuanrong; Grote, Verena A; Steffen, Annika; Boeing, Heiner; Racine, Antoine; Boutron-Ruault, Marie-Christine; Carbonnel, Franck; Peeters, Petra H M; Siersema, Peter D; Fedirko, Veronika; Jenab, Mazda; Riboli, Elio; Bueno-de-Mesquita, Bas

    2012-10-01

    Several studies support a protective effect of dietary magnesium against type 2 diabetes, but a harmful effect for iron. As diabetes has been linked to pancreatic cancer, intake of these nutrients may be also associated with this cancer. We examined the association between dietary intake of magnesium, total iron and heme-iron and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. In total, 142,203 men and 334,999 women, recruited between 1992 and 2000, were included. After an average follow-up of 11.3 years, 396 men and 469 women developed exocrine pancreatic cancer. Hazard ratios and 95% confidence intervals (CIs) were obtained using Cox regression stratified by age and center, and adjusted for energy intake, smoking status, height, weight, and self-reported diabetes status. Neither intake of magnesium, total iron nor heme-iron was associated with pancreatic cancer risk. In stratified analyses, a borderline inverse association was observed among overweight men (body mass index, ≥ 25 kg/m(2) ) with magnesium (HR(per 100 mg/day increase) = 0.79, 95% CI = 0.63-1.01) although this was less apparent using calibrated intake. In female smokers, a higher intake of heme-iron was associated with a higher pancreatic cancer risk (HR (per 1 mg/day increase) = 1.38, 95% CI = 1.10-1.74). After calibration, this risk increased significantly to 2.5-fold (95% CI = 1.22-5.28). Overall, dietary magnesium, total iron and heme-iron were not associated with pancreatic cancer risk during the follow-up period. Our observation that heme-iron was associated with increased pancreatic cancer risk in female smokers warrants replication in additional study populations.

  18. First principles investigation of magnesium antimonite semiconductor compound in two different phases under hydrostatic pressure

    Science.gov (United States)

    Sedighi, Matin; Nia, Borhan Arghavani; Zarringhalam, Hanif; Moradian, Rostam

    2011-09-01

    We investigate the electronic and the structural properties of Mg 3Sb 2 in cubic and hexagonal phases using the full potential-linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory. The effects of hydrostatic pressure on band gap, bandwidths of bands under Fermi energy labeled by B1 and B2 from the top, the energy gap between B1 and B2 (anti-symmetry gap) and also effective masses of electrons and holes are studied using optimized lattice parameters. We observe that the hydrostatic pressure decreases the band gap and the anti-symmetry gap while it increases the bandwidths of all bands below the Fermi energy. The effective masses of electrons and holes for the hexagonal phase depend on pressure in the Γ→ Λ direction. In the cubic phase the effective mass of electrons is independent of pressure and the effective mass of holes depend on the pressure in the Γ→ N direction.

  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. 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

  1. 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

  2. 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...

  3. 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....

  4. Magnesium compounds

    Science.gov (United States)

    Kramer, D.A.

    2012-01-01

    Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.

  5. 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

  6. 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

  7. [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

  8. 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

  9. 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.

  10. 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 ...

  11. 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.

  12. Investigation of residual stresses in welded joints of heat-resistant magnesium alloy ML10 after electrodynamic treatment

    Directory of Open Access Journals (Sweden)

    L.M. Lobanov

    2016-06-01

    Full Text Available In repair of aircraft structures of magnesium alloy ML10, the argon arc non-consumable electrode welding is used. In this case, the residual welding stresses occur in repair welds, being one of the causes for reducing the service characteristics of the restored products. Residual stresses arise as a result of welding. Post-weld heat treatment is used to reduce the residual stresses. The heat treatment, which occurs after welding, increases the cost of repair. This leads to the search for alternative methods to control the stressed state of welded joints, one of which is electrodynamic treatment, which reduces the level of residual stresses in repair welds, and as a consequence, the cost of the welding repair in restoring aircraft structures. It was found from the results of experiments carried out, that the electrodynamic treatment allows reduces the initial level of stresses in welded joints, reaching 120 MPa, to 30 MPa, and at definite geometric characteristics of the specimens forming the field of compressive stresses, the values of which are equal to –50 MPa. It is shown that the optimum distance between the zones of treatment, being 5 mm, provides the guaranteed covering the zones of electrodynamic effect and, as a consequence, the maximum efficiency of the electric dynamic treatment.

  13. 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....

  14. 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.

  15. 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...

  16. 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.

  17. 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...

  18. 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...

  19. 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

  20. 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...

  1. 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...

  2. Magnesium-containing mixed coatings on zirconia for dental implants: mechanical characterization and in vitro behavior.

    Science.gov (United States)

    Pardun, Karoline; Treccani, Laura; Volkmann, Eike; Streckbein, Philipp; Heiss, Christian; Gerlach, Juergen W; Maendl, Stephan; Rezwan, Kurosch

    2015-07-01

    An important challenge in the field of dental and orthopedic implantology is the preparation of implant coatings with bioactive functions that feature a high mechanical stability and at the same time mimic structural and compositional properties of native bone for a better bone ingrowth. This study investigates the influence of magnesium addition to zirconia-calcium phosphate coatings. The mixed coatings were prepared with varying additions of either magnesium oxide or magnesium fluoride to yttria-stabilized zirconia and hydroxyapatite. The coatings were deposited on zirconia discs and screw implants by wet powder spraying. Microstructure studies confirm a porous coating with similar roughness and firm adhesion not hampered by the coating composition. The coating morphology, mechanical flexural strength and calcium dissolution showed a magnesium content-dependent effect. Moreover, the in vitro results obtained with human osteoblasts reveal an improved biological performance caused by the presence of Mg(2+) ions. The magnesium-containing coatings exhibited better cell proliferation and differentiation in comparison to pure zirconia-calcium phosphate coatings. In conclusion, these results demonstrate that magnesium addition increases the bioactivity potential of zirconia-calcium phosphate coatings and is thus a highly suitable candidate for bone implant coatings. PMID:25698722

  3. Magnesium-containing mixed coatings on zirconia for dental implants: mechanical characterization and in vitro behavior.

    Science.gov (United States)

    Pardun, Karoline; Treccani, Laura; Volkmann, Eike; Streckbein, Philipp; Heiss, Christian; Gerlach, Juergen W; Maendl, Stephan; Rezwan, Kurosch

    2015-07-01

    An important challenge in the field of dental and orthopedic implantology is the preparation of implant coatings with bioactive functions that feature a high mechanical stability and at the same time mimic structural and compositional properties of native bone for a better bone ingrowth. This study investigates the influence of magnesium addition to zirconia-calcium phosphate coatings. The mixed coatings were prepared with varying additions of either magnesium oxide or magnesium fluoride to yttria-stabilized zirconia and hydroxyapatite. The coatings were deposited on zirconia discs and screw implants by wet powder spraying. Microstructure studies confirm a porous coating with similar roughness and firm adhesion not hampered by the coating composition. The coating morphology, mechanical flexural strength and calcium dissolution showed a magnesium content-dependent effect. Moreover, the in vitro results obtained with human osteoblasts reveal an improved biological performance caused by the presence of Mg(2+) ions. The magnesium-containing coatings exhibited better cell proliferation and differentiation in comparison to pure zirconia-calcium phosphate coatings. In conclusion, these results demonstrate that magnesium addition increases the bioactivity potential of zirconia-calcium phosphate coatings and is thus a highly suitable candidate for bone implant coatings.

  4. 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.

  5. 75 FR 59935 - Investigational New Drug Safety Reporting Requirements for Human Drug and Biological Products and...

    Science.gov (United States)

    2010-09-29

    ... ``E2A Clinical Safety Data Management: Definitions and Standards for Expedited Reporting'' (60 FR 11284... 0910-AG13 Investigational New Drug Safety Reporting Requirements for Human Drug and Biological Products... safety reporting for human biological products: Laura Rich, Center for Biologics Evaluation and...

  6. Investigation of thermodynamic properties of magnesium chloride amines by HPDSC and TG. For application in a high-lift high-temperature chemical heat pump

    NARCIS (Netherlands)

    Bevers, E.R.T.; Oonk, H.A.J.; Haije, W.G.; Ekeren, P.J. van

    2007-01-01

    The formation as well as the decomposition of magnesium chloride ammonia complexes was studied by high-pressure differential scanning calorimetry (HPDSC) and thermogravimetric analysis (TG). HPDSC runs were performed under constant ammonia pressure conditions to determine the transition temperatures

  7. Magnesium: Potential Roles in Neurovascular Disease

    Directory of Open Access Journals (Sweden)

    Jason J Chang

    2014-04-01

    Full Text Available Objective: Magnesium therapy has been studied extensively in pre-clinical and clinical trials in multiple organ systems. Cerebrovascular diseases are particularly likely to benefit from its neuroprotective properties. This review summarizes current studies of magnesium in a wide range of neurovascular diseases.Methods: We searched relevant terms in the National Library of Medicine PubMed database and selected research including basic science, translational reports, meta-analyses, and clinical studies.Results: Studies examining magnesium administration in ischemic stroke have failed to show any benefit in clinical outcome. Data on magnesium for intracerebral hemorrhage is limited. Preliminary investigations in subarachnoid hemorrhage were promising, but definitive studies did not reveal differences in clinical outcome between magnesium and placebo-treated groups. Studies examining magnesium administration in global ischemia following cardiac arrest suggest a trend toward improved clinical outcome. The strongest evidence for clinically relevant neuroprotection following magnesium administration derives from studies of pre-term infants and patients undergoing cardiac bypass and carotid endarterectomy procedures. Magnesium was found to have an excellent safety profile across all investigations.Conclusions: Magnesium is easy to administer and possesses a favorable safety profile. Its utility as a neuroprotectant in cardiac surgery, carotid enderaterectomy, and pre-term infant hypoxia remain promising. Value as a therapeutic agent in ischemic stroke, intracerebral hemorrhage and subarachnoid hemorrhage is unclear and appears to be limited by late administration. Ongoing clinical trials assessing magnesium administration in the first hours following symptom onset may help clarify the role of magnesium therapy in these disease processes.

  8. 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- ...

  9. 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.

  10. Magnesium and Space Flight.

    Science.gov (United States)

    Smith, Scott M; Zwart, Sara R

    2015-12-08

    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.

  11. 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.

  12. A review on hot tearing of magnesium alloys

    Directory of Open Access Journals (Sweden)

    Jiangfeng Song

    2016-09-01

    Full Text Available Hot tearing is often a major casting defect in magnesium alloys and has a significant impact on the quality of their casting products. Hot tearing of magnesium alloys is a complex solidification phenomenon which is still not fully understood, it is of great importance to investigate the hot tearing behaviour of magnesium alloys. This review attempts to summarize the investigations on hot tearing of magnesium alloys over the past decades. The hot tearing criteria including recently developed Kou's criterion are summarized and compared. The numeric simulation and assessing methods of hot tearing, factors influencing hot tearing, and hot tearing susceptibility (HTS of magnesium alloys are discussed.

  13. 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.

  14. 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...

  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. 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.

  17. Investigation into biologically active constituents of Geum rivale L.

    Science.gov (United States)

    Owczarek, Aleksandra; Gudej, Jan

    2013-01-01

    Aerial and underground parts of Geum rivale (Rosaceae) were investigated. Tiliroside, gallic acid, ellagic acid and a sterol fraction were isolated from aerial parts of the plant. The sterol fraction was analyzed using GC-MS. Eleven phenolic acids were identified in aerial parts of the plant, and eight in underground parts, by means of RP-HPLC analysis. The quantitative determination of phenolic acids, tannins and flavonoids was also carried out.

  18. 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.

  19. 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.

  20. 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)

  1. Effect of biologically relevant ions on the corrosion products formed on alloy AZ31B: an improved understanding of magnesium corrosion.

    Science.gov (United States)

    Jang, Yongseok; Collins, Boyce; Sankar, Jagannathan; Yun, Yeoheung

    2013-11-01

    Simulated physiological solutions mimicking human plasma have been utilized to study the in vitro corrosion of biodegradable metals. However, corrosion and corrosion product formation are different for different solutions with varied responses and, hence, the prediction of in vivo degradation behavior is not feasible based on these studies alone. This paper reports the role of physiologically relevant salts and their concentrations on the corrosion behavior of a magnesium alloy (AZ31B) and subsequent corrosion production formation. Immersion tests were performed for three different concentrations of Ca(2+), HPO4(2-), HCO3(-) to identify the effect of each ion on the corrosion of AZ31B assessed at 1, 3 and 10 days. Time-lapse morphological characterization of the samples was performed using X-ray computed tomography and scanning electron microscopy. The chemical composition of the surface corrosion products was determined by electron dispersive X-ray spectroscopy and X-ray diffraction. The results show that: (1) calcium is not present in the corrosion product layer when only Cl(-) and OH(-) anions are available; (2) the presence of phosphate induces formation of a densely packed amorphous magnesium phosphate corrosion product layer when HPO4(2-) and Cl(-) are present in solution; (3) octacalcium phosphate and hydroxyapatite (HAp) are deposited on the surface of the magnesium alloy when HPO4(2-) and Ca(2+) are present together in NaCl solution (this coating limits localized corrosion and increases general corrosion resistance); (4) addition of HCO3(-) accelerates the overall corrosion rate, which increases with increasing bicarbonate concentration; (5) the corrosion rate decreases due to the formation of insoluble HAp on the surface when HCO3(-), Ca(2+), and HPO4(2-) are present together.

  2. 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

  3. 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.

  4. 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

  5. Investigating Lebanese Grade Seven Biology Teachers Mathematical Knowledge and Skills: A Case Study

    Science.gov (United States)

    Raad, Nawal Abou; Chatila, Hanadi

    2016-01-01

    This paper investigates Lebanese grade 7 biology teachers' mathematical knowledge and skills, by exploring how they explain a visual representation in an activity depending on the mathematical concept "Function". Twenty Lebanese in-service biology teachers participated in the study, and were interviewed about their explanation for the…

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Boron, calcium and magnesium in Kavaratti lagoon water, Lakshadweep Archipelago

    Digital Repository Service at National Institute of Oceanography (India)

    Nasnolkar, C.M.; Salkar, V.R.; Shirodkar, P.V.; Abidi, S.A.H.

    very much lower than that of the surface seawater outside the lagoon indicating their removal. In the lagoon, the calcium and magnesium removal was attributed to their involvement in the biological precipitation of carbonates whereas the removal...

  15. 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.

  16. 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...

  17. 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

  18. 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

  19. Electrochemical impedance spectroscopic investigation of the role of alkaline pre-treatment in corrosion resistance of a silane coating on magnesium alloy, ZE41

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty Banerjee, P. [Department of Chemical Engineering, Monash University, Clayton, VIC-3800 (Australia); CAST Cooperative Research Centre, Hawthorn, VIC-3122 (Australia); Singh Raman, R.K., E-mail: raman.singh@eng.monash.edu.a [Department of Chemical Engineering, Monash University, Clayton, VIC-3800 (Australia); Department of Mechanical and Aerospace Engineering, Monash University, Clayton, VIC-3800 (Australia)

    2011-04-15

    The protective performance of the coatings of bis-1,2-(triethoxysilyl) ethane (BTSE) on ZE41 magnesium alloy with different surface pre-treatments were evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 0.1 M sodium chloride solution. Electrical equivalent circuits were developed based upon hypothetical corrosion mechanisms and simulated to correspond to the experimental data. The morphology and cross section of the alloy subjected to different pre-treatments and coatings were characterized using scanning electron microscope. A specific alkaline pre-treatment of the substrate prior to the coating has been found to improve the corrosion resistance of the alloy.

  20. Discussion about magnesium phosphating

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2016-07-01

    Full Text Available The paper describes results from recently published research focused on production of non-conventional magnesium phosphate Mg3(PO42・4H2O – bobierrite, or MgHPO4・3H2O – newberyite coating for both magnesium alloys and/or mild steel. This new kind of coating is categorized in the context of current state of phosphating technology and its potential advantages and crystal structure is discussed. At the same time, the suitable comparison techniques for magnesium phosphate coating and conventional zinc phosphate coating are discussed.

  1. 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...

  2. 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.

  3. 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.

  4. Rapid recovery from major depression using magnesium treatment.

    Science.gov (United States)

    Eby, George A; Eby, Karen L

    2006-01-01

    , headache, delirium, hallucinations and hyperexcitability, with each of these having been previously documented. The possibility that magnesium deficiency is the cause of most major depression and related mental health problems including IQ loss and addiction is enormously important to public health and is recommended for immediate further study. Fortifying refined grain and drinking water with biologically available magnesium to pre-twentieth century levels is recommended.

  5. 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…

  6. 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…

  7. 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

  8. Introduction to Biological Investigations: A First-Year Experience in Experimental Design and Scientific Communication

    Science.gov (United States)

    Foote, Linda C.; Fitzpatrick, Kathleen A.

    2004-01-01

    Introduction to Biological Investigations is a course that was developed to introduce the scientific method through practical application. This active, student-centered experience fosters fundamental skills that promote creativity, critical thinking, and scientific-communication. The course has been well received by first-year students, and…

  9. 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.

  10. Advances in investigation of new technologies on biological nitrogen removal of waste water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Zhang, J.; Xu, A.; Li, R. [CUMT, Xuzhou (China). School of Environment and Spatial Information

    2004-03-15

    The progresses of biological nitrogen removal from waste water, such as the investigation on shortcut nitrification denitrification, simultaneous nitrification denitrification (SND). Toxic ammonium oxidation (ANAMMOX) and ecology superior nitrification denitrification (ECOSUNIDES) were analyzed and discussed. The advantages of the new technology was compared with the traditional ones. It can be concluded that the new technology is promising for further investigations and applications. 9 refs., 2 figs.

  11. 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.

  12. 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 ...

  13. 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...

  14. Investigating noise tolerance in an efficient engine for inferring biological regulatory networks.

    Science.gov (United States)

    Komori, Asako; Maki, Yukihiro; Ono, Isao; Okamoto, Masahiro

    2015-06-01

    Biological systems are composed of biomolecules such as genes, proteins, metabolites, and signaling components, which interact in complex networks. To understand complex biological systems, it is important to be capable of inferring regulatory networks from experimental time series data. In previous studies, we developed efficient numerical optimization methods for inferring these networks, but we have yet to test the performance of our methods when considering the error (noise) that is inherent in experimental data. In this study, we investigated the noise tolerance of our proposed inferring engine. We prepared the noise data using the Langevin equation, and compared the performance of our method with that of alternative optimization methods. PMID:25790786

  15. 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.

  16. 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

  17. High pressure investigations on hydrous magnesium silicate-phase A using first principles calculations: H---H repulsion and changes in hydrogen bond geometry with compression

    Science.gov (United States)

    Poswal, H. K.; Sharma, Surinder; Sikka, S. K.

    2009-09-01

    We have carried out first principles structural relaxation calculations on the hydrous magnesium silicate Phase A (Mg7Si2O8(OH)6) under high pressures. Our results show that phase A does not undergo any phase transition upto ~ 45 GPa. We find that non-bonded H--H distance reaches a limiting value of 1.85 angstrom at about 45 GPa. The H--H repulsive strain releasing mechanism in Phase A is found to be dramatically different from the hydrogen bond bending one that was proposed by Hofmeister et al1 for Phase B. It is based on the reduction of one of the O-H bond distances with compression.

  18. 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

  19. 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)....

  20. 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.)

  1. 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.

  2. Tethered bilayer lipid membranes (tBLMs): interest and applications for biological membrane investigations.

    Science.gov (United States)

    Rebaud, Samuel; Maniti, Ofelia; Girard-Egrot, Agnès P

    2014-12-01

    Biological membranes play a central role in the biology of the cell. They are not only the hydrophobic barrier allowing separation between two water soluble compartments but also a supra-molecular entity that has vital structural functions. Notably, they are involved in many exchange processes between the outside and inside cellular spaces. Accounting for the complexity of cell membranes, reliable models are needed to acquire current knowledge of the molecular processes occurring in membranes. To simplify the investigation of lipid/protein interactions, the use of biomimetic membranes is an approach that allows manipulation of the lipid composition of specific domains and/or the protein composition, and the evaluation of the reciprocal effects. Since the middle of the 80's, lipid bilayer membranes have been constantly developed as models of biological membranes with the ultimate goal to reincorporate membrane proteins for their functional investigation. In this review, after a brief description of the planar lipid bilayers as biomimetic membrane models, we will focus on the construction of the tethered Bilayer Lipid Membranes, the most promising model for efficient membrane protein reconstitution and investigation of molecular processes occurring in cell membranes.

  3. 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...

  4. 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. ...

  5. GOmotif: A web server for investigating the biological role of protein sequence motifs

    Directory of Open Access Journals (Sweden)

    He Runtao

    2011-09-01

    Full Text Available Abstract Background Many proteins contain conserved sequence patterns (motifs that contribute to their functionality. The process of experimentally identifying and validating novel protein motifs can be difficult, expensive, and time consuming. A means for helping to identify in advance the possible function of a novel motif is important to test hypotheses concerning the biological relevance of these motifs, thus reducing experimental trial-and-error. Results GOmotif accepts PROSITE and regular expression formatted motifs as input and searches a Gene Ontology annotated protein database using motif search tools. The search returns the set of proteins containing matching motifs and their associated Gene Ontology terms. These results are presented as: 1 a hierarchical, navigable tree separated into the three Gene Ontology biological domains - biological process, cellular component, and molecular function; 2 corresponding pie charts indicating raw and statistically adjusted distributions of the results, and 3 an interactive graphical network view depicting the location of the results in the Gene Ontology. Conclusions GOmotif is a web-based tool designed to assist researchers in investigating the biological role of novel protein motifs. GOmotif can be freely accessed at http://www.gomotif.ca

  6. 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.

  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. 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

    2016-12-01

    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.

  9. 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.

  10. 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.

  11. A miniaturised isotachophoresis method for magnesium determination.

    Science.gov (United States)

    Prest, Jeff E; Baldock, Sara J; Fielden, Peter R; Goddard, Nicholas J; Treves Brown, Bernard J

    2009-07-01

    The use of malonic acid as a complexing agent has enabled a new method to be devised to allow the determination of magnesium to be made using miniaturised isotachophoresis. Using a leading electrolyte of 10 mmol L(-1) caesium hydroxide and 2 mmol L(-1) malonic acid at pH 5.1 gave the method a high specificity towards magnesium. Investigations using a poly(methyl methacrylate) chip device with an integrated conductivity detector showed that no interference from calcium, strontium, barium and sodium should occur. The method was found to be linear over the range of magnesium concentrations from 0.625 to 75 mg L(-1) and the limit of detection was calculated to be 0.45 mg L(-1). Separations were demonstrated with water samples but the procedure should also be applicable to more complex sample matrices such as inorganic explosive residues, blood or urine. PMID:19205676

  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

    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......) is 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...... 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 phenotypes. We...

  13. 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...

  14. 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)

  15. 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.

  16. 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.

  17. 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...... magnesium and its contribution to the carbonate endmember is unclear. Therefore, direct estimation of the source of dissolved magnesium based on magnesium mass balance may become a powerful tool to quantify weathering fluxes but needs better knowledge of the carbonate endmember composition....

  18. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Trewyn, Brian G. [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    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

  1. 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.

  2. FOCUS ON MAGNESIUM BASED DRUGS

    Directory of Open Access Journals (Sweden)

    I. I. Esenova

    2011-01-01

    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.

  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. AZ31变形镁合金化学镀前无铬酸洗工艺研究%An Investigation of Chromium-Free Pickling Process for Electroless Nickel Plating on AZ 31 Wrought Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    秦铁男; 马立群; 贺忠臣; 姚妍; 丁毅

    2011-01-01

    主要研究了AZ 31变形镁合金化学镀前的磷酸-硝酸-氢氟酸混合酸洗工艺及各组分对镁合金基体的腐蚀失重表面形貌、镀层与基体的截面形貌和结合力的影响.结果表明:氢氟酸的加入可以有效降低酸洗反应速率并防止新鲜的镁合金基体表面的再次氧化;硝酸的体积分数对镁合金表面形貌的改变有较大影响;当磷酸-硝酸-氢氟酸的体积分数分别为300 mL/L,60 mL/L和100 mL/L时,镀层与基体的结合力最好.%A phosphoric acid-nitric acid-hydrofuoric acid mixed acid pickling process was studied for electroless nickel plating on AZ 31 wrought magnesium alloy sheet. The effects of pickle components on corrosion weight loss, surface morphology, cross section morphology and adhesion strength between the substrate and coating were investigated. The results show that addition of hydrofluoric acid can effectively reduce the rate of pickling reaction and protect the fresh substrate from being Oxidized again. The volume fraction of nitric acid has a great impact on changes of the surface morphology of magnesium substrate. The best adhesion strength between the substrate and the coating is achieved when the pickle solution contains 300 mL/L phosphoric acid, 60 mL/L nitric acid and 100 mL/L hydrofluoric acid.

  7. 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

  8. 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.

  9. 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.

  10. Custom AFM for X-ray beamlines: in situ biological investigations under physiological conditions.

    Science.gov (United States)

    Gumí-Audenis, B; Carlà, F; Vitorino, M V; Panzarella, A; Porcar, L; Boilot, M; Guerber, S; Bernard, P; Rodrigues, M S; Sanz, F; Giannotti, M I; Costa, L

    2015-11-01

    A fast atomic force microscope (AFM) has been developed that can be installed as a sample holder for grazing-incidence X-ray experiments at solid/gas or solid/liquid interfaces. It allows a wide range of possible investigations, including soft and biological samples under physiological conditions (hydrated specimens). The structural information obtained using the X-rays is combined with the data gathered with the AFM (morphology and mechanical properties), providing a unique characterization of the specimen and its dynamics in situ during an experiment. In this work, lipid monolayers and bilayers in air or liquid environment have been investigated by means of AFM, both with imaging and force spectroscopy, and X-ray reflectivity. In addition, this combination allows the radiation damage induced by the beam on the sample to be studied, as has been observed on DOPC and DPPC supported lipid bilayers under physiological conditions. PMID:26524300

  11. 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

  12. 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)

  13. Custom AFM for X-ray beamlines: in situ biological investigations under physiological conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gumí-Audenis, B. [ESRF, The European Synchrotron, Grenoble (France); Institute for Bioengineering of Catalonia (IBEC), Barcelona (Spain); Physical Chemistry Department, Universitat de Barcelona, Barcelona (Spain); Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid (Spain); Carlà, F. [ESRF, The European Synchrotron, Grenoble (France); Vitorino, M. V. [University of Lisboa, Falculty of Science, Biosystems and Integrative Sciences Institute - BIOISI, Lisbon (Portugal); Panzarella, A. [ESRF, The European Synchrotron, Grenoble (France); Porcar, L. [Institut Laue-Langevin, Grenoble (France); Boilot, M. [ORTEC, Marseille (France); Guerber, S. [CEA, LETI Grenoble (France); Bernard, P. [ESRF, The European Synchrotron, Grenoble (France); Rodrigues, M. S. [University of Lisboa, Falculty of Science, Biosystems and Integrative Sciences Institute - BIOISI, Lisbon (Portugal); Sanz, F.; Giannotti, M. I. [Institute for Bioengineering of Catalonia (IBEC), Barcelona (Spain); Physical Chemistry Department, Universitat de Barcelona, Barcelona (Spain); Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid (Spain); Costa, L., E-mail: luca.costa@esrf.fr [ESRF, The European Synchrotron, Grenoble (France)

    2015-09-30

    The performance of a custom atomic force microscope for grazing-incidence X-ray experiments on hydrated soft and biological samples is presented. A fast atomic force microscope (AFM) has been developed that can be installed as a sample holder for grazing-incidence X-ray experiments at solid/gas or solid/liquid interfaces. It allows a wide range of possible investigations, including soft and biological samples under physiological conditions (hydrated specimens). The structural information obtained using the X-rays is combined with the data gathered with the AFM (morphology and mechanical properties), providing a unique characterization of the specimen and its dynamics in situ during an experiment. In this work, lipid monolayers and bilayers in air or liquid environment have been investigated by means of AFM, both with imaging and force spectroscopy, and X-ray reflectivity. In addition, this combination allows the radiation damage induced by the beam on the sample to be studied, as has been observed on DOPC and DPPC supported lipid bilayers under physiological conditions.

  14. Rolling of microalloyed magnesium sheets

    Energy Technology Data Exchange (ETDEWEB)

    Sotirov, N.; Riemelmoser, F.O.; Kuhlein, M.; Kettner, M. [ARC Leichmetallkompetenzzentrum GmbH, Ranshofen (Austria); Uggowitzer, P.J. [ETH Zurich, Zurich (Switzerland). Dept. of Materials, Laboratory of Metal Physics and Technology; Spencer, K. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Materials Technology Lab

    2007-07-01

    This paper described a rolling process for a micro-alloyed zinc-manganese (Zn-Ca-Ag-Mn) magnesium alloy. The micro-alloyed magnesium alloy L1 was investigated in order to achieve a finer grain structure and to avoid normal grain growth during rolling. Rolling parameters included billet temperature; rolls temperature and rolls radius; rolling speed; and lubrication. Standard tensile tests were conducted with the rolled alloy L1 flat specimens at room temperature with a test length of 50 mm and a test width of 12.5 mm. Specimens heat treated at 100 degrees C and 200 degrees C showed good balance of strength and elongation. Elongation increased with increasing heat treatment times. Results of the tests demonstrated that the Zn-Ca-Ag-Mn alloy L1 showed exceptionally high elongations to fracture at room temperatures. A pronounced work hardening regime was also observed. It was concluded that the grain structure of the L1 alloy was not influenced after heat treatments until temperatures reached 350 degrees C for 20 minutes. Significant grain coarsening occurred after preliminary heat treatments of 400 degrees C. 7 refs., 1 tab., 6 figs.

  15. 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

  16. Magnesium fluoride recovery method

    Science.gov (United States)

    Gay, Richard L.; McKenzie, Donald E.

    1989-01-01

    A method of obtaining magnesium fluoride substantially free from radioactive uranium from a slag containing the same and having a radioactivity level of at least about 7000 pCi/gm. The slag is ground to a particle size of about 200 microns or less. The ground slag is contacted with an acid under certain prescribed conditions to produce a liquid product and a particulate solid product. The particulate solid product is separated from the liquid and treated at least two more times with acid to produce a solid residue consisting essentially of magnesium fluoride substantially free of uranium and having a residual radioactivity level of less than about 1000 pCi/gm. In accordance with a particularly preferred embodiment of the invention a catalyst and an oxidizing agent are used during the acid treatment and preferably the acid is sulfuric acid having a strength of about 1.0 Normal.

  17. 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....

  18. Bioavailability, tissue distribution and hypoglycaemic effect of vanadium in magnesium-deficient rats.

    Science.gov (United States)

    Sánchez, Cristina; Torres, Miguel; Bermúdez-Peña, María C; Aranda, Pilar; Montes-Bayón, María; Sanz-Medel, Alfredo; Llopis, Juan

    2011-12-01

    Vanadium is an element whose role as a micronutrient and hypoglycaemic drug has yet to be fully clarified. The present study was undertaken to investigate the bioavailability and tissue distribution of vanadium and its interactions with magnesium in healthy and in magnesium-deficient rats, in order to determine its role as a micronutrient and antidiabetic agent. Four groups were used: control (456.4 mg magnesium and 0.06 mg vanadium/kg food); control treated with 1mg vanadium/day; magnesium-deficient (164.4 mg magnesium/kg food and 0.06 mg vanadium/kg food); and magnesium-deficient treated with 1 mg vanadium/day. The vanadium was supplied in the drinking water as bis(maltolato)oxovanadium (IV). The experiment had a duration of five weeks. We measured vanadium and magnesium in excreta, serum, skeletal muscle, kidney, liver, adipose tissue and femur. Fasting glucose, insulin and total antioxidant status (TAS) in serum were studied. The vanadium treatment applied to the control rats reduced the absorption, retention, serum level and femur content of magnesium. Magnesium deficiency increased the retention and serum level of vanadium, the content of vanadium in the kidney, liver and femur (organs where magnesium had been depleted), serum glycaemia and insulin, and reduced TAS. V treatment given to magnesium-deficient rats corrected magnesium content in muscle, kidney and liver and levels of serum glucose, insulin and TAS. In conclusion, our results show interactions between magnesium and vanadium in the digestive and renal systems. Treatment with vanadium to magnesium-deficient rats corrected many of the alterations that had been generated by the magnesium deficiency.

  19. 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.

  20. 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 ...

  1. Investigation on clarification of secondary premed juice with magnesium and chitosan composite coagulantion%二压汁镁盐-壳聚糖复合混凝澄清研究

    Institute of Scientific and Technical Information of China (English)

    玉泉; 周少基; 刘慧霞; 覃晓雨; 黄威威

    2013-01-01

    为了实施甘蔗糖厂—压汁与二压汁的分流澄清工艺,进行了在高pH值条件下用硫酸镁和壳聚糖对二压汁进行单一和复合混凝剂的澄清试验.通过改变pH值、温度、澄清剂添加量,研究单一混凝剂及单因素条件对二压汁澄清效果的影响;在此基础上采用响应面分析法优化两种澄清剂的复合混凝澄清及其条件.单因素试验研究结果表明,在高pH值条件下两种混凝剂对二压汁均有良好的澄清效果,硫酸镁的脱色及提净效率均优于壳聚糖.复合混凝实验结果显示,硫酸镁与壳聚糖对二压汁的清净具有协同作用,硫酸镁-壳聚糖复合混凝的澄清效果优于单一混凝剂澄清;最佳工艺条件为硫酸镁0.5%,壳聚糖464 mg/kg,温度60℃,pH =11.06.进行了二压汁的硫酸镁和壳聚糖复合混凝澄清与传统亚硫酸法工艺澄清的对比试验,在最优工艺条件下,复合混凝剂的高pH澄清与传统亚硫酸澄清工艺相比,清汁纯度提高约6AP,脱色率提高约25%.%To clarify the firstly and secondary pressed juice, clarification of the secondary pressed juice by coagulation with magnesium sulfate and chitosan under high pH was investigated. Single coagulantion experiments were performed under varying pH value, temperature, and dosages of coagulants. The experimental investigation of composite coagulation with optimal conditions was then performed using the surface response method. The single coagultion experiments showed that the cation-ic coagulants showed excellent clarifying effect on the secondary pressed juice at high pH value with magnesium sulfate superior to chitosan in purification and decoloration. The composite coagulation was better than the single coagulation in clarification, showing the synergistic clarifying action between the two coagulants. The optimal condition was dosage being 0. 5% of magnesium sulfate and 464 mg/kg chitosan, temperature 60 ℃ ,pH =11. 06. Compared to the

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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

  8. Hydrostatic extrusion of magnesium alloys

    NARCIS (Netherlands)

    Sillekens, W.H.; Bohlen, J.

    2012-01-01

    This chapter deals with the capabilities and limitations of the hydrostatic extrusion process for the manufacturing of magnesium alloy sections. Firstly, the process basics for the hydrostatic extrusion of materials in general and of magnesium in particular are introduced. Next, some recent research

  9. 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

  10. 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

  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......The placenta and the umbilical cord obtained from 18 women with pregnancy-induced hypertension were investigated by light microscopy. The umbilical artery was studied by electron microscopy. 10 placentae and umbilical cords from normal pregnancies served as controls. The study was performed...... weight and placental weight significantly. Light microscopic study of the placentae and the umbilical cord arteries showed no difference between the three groups concerning the occurrence of infarctions, cytotrophoblastic hyperplasia, vasculo-syncytial membranes, basement membrane thickening, stromal...

  12. 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 ...

  13. Investigating Biological Control Agents for Controlling Invasive Populations of the Mealybug Pseudococcus comstocki in France.

    Directory of Open Access Journals (Sweden)

    Thibaut Malausa

    Full Text Available Pseudococcus comstocki (Hemiptera: Pseudococcidae is a mealybug species native to Eastern Asia and present as an invasive pest in northern Italy and southern France since the start of the century. It infests apple and pear trees, grapevines and some ornamental trees. Biocontrol programmes against this pest proved successful in central Asia and North America in the second half of the 20th century. In this study, we investigated possible biocontrol agents against P. comstocki, with the aim of developing a biocontrol programme in France. We carried out systematic DNA-barcoding at each step in the search for a specialist parasitoid. First we characterised the French target populations of P. comstocki. We then identified the parasitoids attacking P. comstocki in France. Finally, we searched for foreign mealybug populations identified a priori as P. comstocki and surveyed their hymenopteran parasitoids. Three mealybug species (P. comstocki, P. viburni and P. cryptus were identified during the survey, together with at least 16 different parasitoid taxa. We selected candidate biological control agent populations for use against P. comstocki in France, from the species Allotropa burrelli (Hymenoptera: Platygastridae and Acerophagus malinus (Hymenoptera: Encyrtidae. The coupling of molecular and morphological characterisation for both pests and natural enemies facilitated the programme development and the rejection of unsuitable or generalist parasitoids.

  14. Investigating Biological Control Agents for Controlling Invasive Populations of the Mealybug Pseudococcus comstocki in France

    Science.gov (United States)

    Malausa, Thibaut; Delaunay, Mathilde; Fleisch, Alexandre; Groussier-Bout, Géraldine; Warot, Sylvie; Crochard, Didier; Guerrieri, Emilio; Delvare, Gérard; Pellizzari, Giuseppina; Kaydan, M. Bora; Al-Khateeb, Nadia; Germain, Jean-François; Brancaccio, Lisa; Le Goff, Isabelle; Bessac, Melissa; Ris, Nicolas; Kreiter, Philippe

    2016-01-01

    Pseudococcus comstocki (Hemiptera: Pseudococcidae) is a mealybug species native to Eastern Asia and present as an invasive pest in northern Italy and southern France since the start of the century. It infests apple and pear trees, grapevines and some ornamental trees. Biocontrol programmes against this pest proved successful in central Asia and North America in the second half of the 20th century. In this study, we investigated possible biocontrol agents against P. comstocki, with the aim of developing a biocontrol programme in France. We carried out systematic DNA-barcoding at each step in the search for a specialist parasitoid. First we characterised the French target populations of P. comstocki. We then identified the parasitoids attacking P. comstocki in France. Finally, we searched for foreign mealybug populations identified a priori as P. comstocki and surveyed their hymenopteran parasitoids. Three mealybug species (P. comstocki, P. viburni and P. cryptus) were identified during the survey, together with at least 16 different parasitoid taxa. We selected candidate biological control agent populations for use against P. comstocki in France, from the species Allotropa burrelli (Hymenoptera: Platygastridae) and Acerophagus malinus (Hymenoptera: Encyrtidae). The coupling of molecular and morphological characterisation for both pests and natural enemies facilitated the programme development and the rejection of unsuitable or generalist parasitoids. PMID:27362639

  15. 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%.

  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. Investigation of formalin influence over hard and soft biological tissues fluorescent spectra in vitro

    Science.gov (United States)

    Borisova, E.; Uzunov, Tz.; Vladimirov, B.; Avramov, L.

    2007-05-01

    In order to investigate the formalin influence over fluorescence properties of hard and soft biological tissues during conservation, emission spectra have been registered. Nitrogen laser at 337 nm and light-emitting diode with maximum at 405 nm have been used as excitation sources. For investigation of formalin influence over hard tissues, an experiment was made on teeth samples. Sound teeth were demineralized with a phosphoric acid for 10 seconds to obtain enamel structure near to the tooth lesion, and were fixed in formalin. Before and after teeth treatment spectra from the areas of interest were detected. There were not observed changes in the shape of the teeth spectra, related to the introduction of formalin fluorescence. Samples from mucosa of esophagus and stomach, where initially an ALA/Protoporphyrin IX diagnosis was applied, were used as soft tissue specimens. After fluorescent diagnosis in vivo biopsy samples were obtained from normal and cancerous areas and were conserved in formalin. Initially, spectrum observed has one autofluorescence maximum from the mucous tissue at 500-600 nm and secondary maxima from the protoporphyrin fluorescence at 635 nm and 720 nm, as well as pronounced minima at 540 and 575 nm related to hemoglobin absorption. After formalin conservation hemoglobin absorption was strongly reduced that increases mucous emission signal in green-yellow spectral region. Simultaneously the maxima at 635 nm and 720 nm were reduced. As conclusion we could say that formalin has negligible influence over fluorescence spectra of conserved hard tissues and has more pronounced influence over fluorescence spectra obtained in the case of soft tissue conservation, which has to be taking into account in measurements in vitro.

  18. Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system.

    Science.gov (United States)

    Hu, Zhi-Rong; Sötemann, S; Moodley, R; Wentzel, M C; Ekama, G A

    2003-08-01

    A systematic lab-scale experimental investigation is reported for the external nitrification (EN) biological nutrient removal (BNR) activated sludge (ENBNRAS) system, which is a combined fixed and suspended medium system. The ENBNRAS system was proposed to intensify the treatment capacity of BNR-activated sludge (BNRAS) systems by addressing two difficulties often encountered in practice: (a) the long sludge age for nitrification requirement; and (b) sludge bulking. In the ENBNRAS system, nitrification is transferred from the aerobic reactor in the suspended medium activated sludge system to a fixed medium nitrification system. Thus, the sludge age of the suspended medium activated sludge system can be reduced from 20 to 25 days to 8 to 10 days, resulting in a decrease in reactor volume per ML wastewater treated of about 30%. Furthermore, the aerobic mass fraction can also be reduced from 50% to 60% to 55% (if the anaerobic mass fraction is 15%), and thus complete denitrification in the anoxic reactors becomes possible. Research indicates that both the short sludge age and complete denitrification could ameliorate anoxic aerobic (AA) or low food/microorganism (F/M) ratio filamentous bulking, and hence reduce the surface area of secondary settling tanks or increase the treatment capacity of existing systems. The lab-scale experimental investigations indicate that the ENBNRAS system can obtain: (i) very good chemical oxygen demand (COD) removal, even with an aerobic mass fraction as low as 20%; (ii) high nitrogen removal, even for a wastewater with a high total kjeldahl nitrogen (TKN)/COD ratio, up to 0.14; (iii) adequate settling sludge (diluted sludge volume index [DSVI] <100 mL/g); and (iv) a significant reduction in oxygen demand.

  19. 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

  20. 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

  1. 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…

  2. 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…

  3. 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...

  4. 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...

  5. 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

  6. 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

  7. 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).

  8. 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...

  9. 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...

  10. 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.

  11. 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

  12. Renal control of calcium, phosphate, and magnesium homeostasis.

    Science.gov (United States)

    Blaine, Judith; Chonchol, Michel; Levi, Moshe

    2015-07-01

    Calcium, phosphate, and magnesium are multivalent cations that are important for many biologic and cellular functions. The kidneys play a central role in the homeostasis of these ions. Gastrointestinal absorption is balanced by renal excretion. When body stores of these ions decline significantly, gastrointestinal absorption, bone resorption, and renal tubular reabsorption increase to normalize their levels. Renal regulation of these ions occurs through glomerular filtration and tubular reabsorption and/or secretion and is therefore an important determinant of plasma ion concentration. Under physiologic conditions, the whole body balance of calcium, phosphate, and magnesium is maintained by fine adjustments of urinary excretion to equal the net intake. This review discusses how calcium, phosphate, and magnesium are handled by the kidneys.

  13. 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

  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. 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...

  16. 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

  17. 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

  18. 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.

  19. Development of a General Modeling Framework for Investigating Complex Interactions among Biological and Physical Ecosystem Dynamics

    Science.gov (United States)

    Bennett, C.; Poole, G. C.; Kimball, J. S.; Stanford, J. A.; O'Daniel, S. J.; Mertes, L. A.

    2005-05-01

    Historically, physical scientists have developed models with highly accurate governing equations, while biologists have excelled at abstraction (the strategic simplification of system complexity). These different modeling paradigms yield biological (e.g. food web) and physical (e.g. hydrologic) models that can be difficult to integrate. Complex biological dynamics may be impossible to represent with governing equations. Conversely, physical processes may be oversimplified in biological models. Using agent-based modeling, a technique applied widely in social sciences and economics, we are developing a general modeling system to integrate accurate representations of physical dynamics such as water and heat flux with abstracted biological processes such as nutrient transformations. The modeling system represents an ecosystem as a complex integrated network of intelligent physical and biological "agents" that store, transform, and trade ecosystem resources (e.g., water, heat, nutrients, carbon) using equations that describe either abstracted concepts and/or physical laws. The modular design of the system allows resource submodels to be developed independently and installed into the simulation architecture. The modeling system provides a useful heuristic tool to support integrated physical and biological research topics, such as the influence of hydrologic dynamics and spatio-temporal physical heterogeneity on trophic (food web) dynamics and/or nutrient cycling.

  20. Magnesium sulphate for fetal neuroprotection

    DEFF Research Database (Denmark)

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

    2013-01-01

    ,494,500 is obtained for each case of CP averted when magnesium sulphate is administered to patients in whom preterm birth is threatened. CONCLUSIONS: Administration of magnesium sulphate to patients in whom preterm birth is imminent is a dominant (i.e. cost-effective) strategy, no matter what cost perspective...... or measure of effectiveness is used. Administration of magnesium sulphate to patients in whom preterm birth is threatened is a dominant strategy from a societal perspective and is very likely to be cost-effective from a health system perspective.......BACKGROUND: The aim of this study was to assess the cost-effectiveness of administering magnesium sulphate to patients in whom preterm birth at 

  1. 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...

  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. 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.

  4. Electrolytic deposition of aluminium-magnesium-alloys from electrolytes containing organo-aluminium complexes; Elektrolytische Abscheidung von Aluminium-Magnesium-Legierungen aus aluminiumorganischen Komplexelektrolyten

    Energy Technology Data Exchange (ETDEWEB)

    Lehmkuhl, H.; Mehler, K.; Bongard, H.; Tesche, B. [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany); Reinhold, B. [Audi AG, Ingolstadt (Germany). Technische Entwicklung

    2000-10-01

    The galvanic deposition of pure aluminium from fluoride-containing electrolytes has been developed further and for the first time aluminium and magnesium have been deposited from a toluene-solution of a halide-free organo-aluminium complex electrolyte. The rate of incorporation of magnesium can be controlled over a wide range by either adjusting the composition of the aluminium-magnesium anode or by using separate aluminium or magnesium anodic circuits. The current efficiency for both anode and cathode approaches 100%. The resulting coating is optically attractive and, depending upon the magnesium-content or the cathodic current density, can be formed as a dull or polished surface. Investigations using an electron microscope show that the surface, in contrast to that of pure aluminium, consists of spherical particles. The aluminium-magnesium coating provides excellent protection against the corrosion of magnesium components. Electrochemical investigations using, for example 25% by weight magnesium incorporation, indicate a pronounced passivity interval compared to the alloy AZ91hp. In contrast to galvanic zinc-plated and silicate-sealed examples, cyclic corrosion tests on screws simulating 10 years of exposure, show no corrosion. (orig.)

  5. Real-time neutron scattering investigations of biological signal transduction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    May, Roland [Institut Laue-Langevinx, Grenoble Cedex (France); Hendriks, Johnny [Vrije Universiteit Amsterdam, Amsterdam (Netherlands); Crielaard, Wim [Swammerdam Institute for Life Sciences and Academic Center for Dentistry, University of Amsterdam, Amsterdam (Netherlands)

    2005-07-01

    During their catalytic cycle, proteins involved in biological signal transduction undergo unexpectedly large conformational changes, which are at the core of their biological functioning. Until now it has been extremely difficult to obtain experimental insight into the nature of these conformational changes. Mathematical modeling and time-resolved X-ray crystallography have resulted in probable routes along which these conformational changes may take place, but so far this fundamental biological phenomenon has hardly been tackled experimentally. Here, we report on an attempt to observe structural changes in Photoactive Yellow Protein with time-resolved small-angle neutron scattering using diffractometer D22 at the high-flux reactor of the Institut Laue-Langevin, Grenoble, France.

  6. 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

  7. 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

  8. 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.

  9. Magnesium supplementation through seaweed calcium extract rather than synthetic magnesium oxide improves femur bone mineral density and strength in ovariectomized rats.

    Science.gov (United States)

    Bae, Yun Jung; Bu, So Young; Kim, Jae Young; Yeon, Jee-Young; Sohn, Eun-Wha; Jang, Ki-Hyo; Lee, Jae-Cheol; Kim, Mi-Hyun

    2011-12-01

    Commercially available seaweed calcium extract can supply high amounts of calcium as well as significant amounts of magnesium and other microminerals. The purpose of this study was to investigate the degree to which the high levels of magnesium in seaweed calcium extract affects the calcium balance and the bone status in ovariectomized rats in comparison to rats supplemented with calcium carbonate and magnesium oxide. A total of 40 Sprague-Dawley female rats (7 weeks) were divided into four groups and bred for 12 weeks: sham-operated group (Sham), ovariectomized group (OVX), ovariectomized with inorganic calcium and magnesium supplementation group (OVX-Mg), and ovariectomized with seaweed calcium and magnesium supplementation group (OVX-SCa). All experimental diets contained 0.5% calcium. The magnesium content in the experimental diet was 0.05% of the diet in the Sham and OVX groups and 0.1% of the diet in the OVX-Mg and OVX-SCa groups. In the calcium balance study, the OVX-Mg and OVX-SCa groups were not significantly different in calcium absorption compared to the OVX group. However, the femoral bone mineral density and strength of the OVX-SCa group were higher than those of the OVX-Mg and OVX groups. Seaweed calcium with magnesium supplementation or magnesium supplementation alone did not affect the serum ALP and CTx levels in ovariectomized rats. In summary, consumption of seaweed calcium extract or inorganic calcium carbonate with magnesium oxide demonstrated the same degree of intestinal calcium absorption, but only the consumption of seaweed calcium extract resulted in increased femoral bone mineral density and strength in ovariectomized rats. Our results suggest that seaweed calcium extract is an effective calcium and magnesium source for improving bone health compared to synthetic calcium and magnesium supplementation.

  10. 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

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

    Science.gov (United States)

    Long, Marcus J C; Poganik, Jesse R; Aye, Yimon

    2016-03-23

    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.

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

    Science.gov (United States)

    Long, Marcus J C; Poganik, Jesse R; Aye, Yimon

    2016-03-23

    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

  13. Inquiry-based Investigation in Biology Laboratories: Does Neem Provide Bioprotection against Bean Beetles?

    Science.gov (United States)

    Pearce, Amy R.; Sale, Amanda Lovelace; Srivatsan, Malathi; Beck, Christopher W.; Blumer, Lawrence S.; Grippo, Anne A.

    2013-01-01

    We developed an inquiry-based biology laboratory exercise in which undergraduate students designed experiments addressing whether material from the neem tree ("Azadirachta indica") altered bean beetle ("Callosobruchus maculatus") movements and oviposition. Students were introduced to the bean beetle life cycle, experimental…

  14. 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.

  15. 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

  16. 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,…

  17. 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...

  18. Mass Transfer and Kinetics Study of Heterogeneous Semi-Batch Precipitation of Magnesium Carbonate

    DEFF Research Database (Denmark)

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

    2014-01-01

    Precipitation kinetics and mass transfer of magnesium carbonate (MgCO3) hydrates from a reaction of magnesium hydroxide (Mg(OH)(2)) and CO2 were analyzed. The effect of CO2 flow rate and mixing intensity on precipitation was investigated under ambient temperature and atmospheric pressure. Raman...

  19. 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

  20. Synthesis of magnesium silicate from wheat husk ash: Effects of parameters on structural and surface properties

    Directory of Open Access Journals (Sweden)

    Pinar Terzioglu

    2012-11-01

    Full Text Available In the present study, magnesium silicate was produced by using wheat husk ash. Wheat husk was burned at 600 °C to obtain an amorphous ash structure, and the ash was processed with sodium hydroxide solution with heat to extract silica. Sodium silicate solution and magnesium salts were used to synthesize magnesium silicate. The present study investigates effects of the feeding rate on magnesium silicate production (0.6 mL/min, 35 mL/min, 70 mL/min, the type of magnesium salt (MgSO4 • 7H2O or MgCl2 • 6H2O, temperature (25 °C or 50 °C, and the washing agent (water and acetone on the chemical composition and surface characteristics of magnesium silicate. The results demonstrated that all of the variables affected the surface characteristics of magnesium silicate, such as surface area, particle size, and pore volume. However, it was also observed that the studied parameters did not affect the chemical composition of magnesium silicate. The wheat husk ash-based magnesium silicates obtained in the experimental study had a BET surface area ranging from 79 to 91 m2/g and a particle size varying from 42 to 63 µm.

  1. 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.

  2. 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.

  3. 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...

  4. 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 ...

  5. Investigating graphesthesia task performance in the biological relatives of schizophrenia patients.

    Science.gov (United States)

    Chang, Bernard P; Lenzenweger, Mark F

    2004-01-01

    This study compared the performance of 39 biological relatives of persons with schizophrenia to that of 30 normal adult controls on graphesthesia processing, a complex somatosensory processing task. The relatives performed significantly worse on the graphesthesia task compared to the healthy controls. The relatives and control subjects, however, did not differ on two neurocognitive control tasks. These data are interpreted within the context of a somatosensory deficit linked to schizophrenia liability.

  6. 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.

  7. Biochemical investigation and biological evaluation of the methanolic extract of the leaves of Nyctanthes arbortristis in vitro

    Institute of Scientific and Technical Information of China (English)

    Repon Kumer Saha; Srijan Acharya; Syed Sohidul Haque Shovon; Apurba Sarker Apu; Priyanka Roy

    2012-01-01

    Objective: Nyctanthes arbortristis is a common plant in Bangladesh. The objective of our research was to biochemical and biological analysis of the methanolic extract of the dried leaves of Nyctanthesarbortristis found in Bangladesh. Methods: We investigated the presence of polyphenols, flavanoids and other types of compounds by thin layer chromatography, infrared spectroscopy, and UV spectroscopy analysis. We performed antioxidant assay by colorimetric methods. We investigated antibacterial assay by disk diffusion method. Cell surface receptor binding assay was performed by hemagglutination inhibition assay and hemolysis assay. Results: Methanolic extract of the leaves of Nyctanthes arbortristis contains flavanoids and other biologically active compounds. The extract showed antioxidant, peroxide scavenging and total reducing activity. The extract also showed antibacterial activities against several strains of bacteria. It also showed hemaglutination inhibition activities and hydrogen peroxide induced hemolysis inhibition activity in human blood cells. Conclusions: Therefore, Nyctanthes arbortristis may be considered as a plant of various health benefits.

  8. 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.

  9. 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.)

  10. 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.

  11. Investigation of natural lipid-phenolic interactions on biological properties of virgin olive oil.

    Science.gov (United States)

    Alu'datt, Muhammad H; Rababah, Taha; Ereifej, Khalil; Gammoh, Sana; Alhamad, Mohammad N; Mhaidat, Nizar; Kubow, Stan; Johargy, Ayman; Alnaiemi, Ola J

    2014-12-10

    There is limited knowledge regarding the impact of naturally occurring lipid-phenolic interactions on the biological properties of phenolics in virgin olive oil. Free and bound phenolics were isolated via sequential methanolic extraction at 30 and 60 °C, and were identified and quantified using reversed phase high performance liquid chromatography, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), and gas chromatography. Decreased oleic acid concentrations and increased concentrations of palmitoleic acid, stearic, linoleic, and linolenic acids were observed in virgin olive oil after removal of free and bound lipid phenolic compounds. The presence of p-hydroxybenzoic acid and tyrosol bound to glycerides was determined via LC-MS/MS, which indicates natural lipid-phenolic interactions in virgin olive oil. Both free and lipid bound phenolic extracts exerted antiproliferative activities against the CRC1 and CRC5 colorectal cancer cell lines. The present work indicates that naturally occurring lipid-phenolic interactions can affect the biological properties of phenolics in virgin olive oil.

  12. 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.

  13. "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

  14. 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

  15. 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)

  16. Intravenous magnesium for acute asthma?

    Science.gov (United States)

    2003-10-01

    Each year in the UK, around 1,500 people die from asthma. Standard treatment has been based on bronchodilators (e.g. beta 2-stimulants) and anti-inflammatory drugs (corticosteroids). The recently revised British Guideline on the Management of Asthma suggests also using a single dose of i.v. magnesium sulphate in patients with acute severe asthma, an unlicensed indication. Here we discuss the rationale for giving i.v. magnesium and whether it offers any advantage for patients with acute severe asthma.

  17. 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...

  18. 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...

  19. 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....

  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. 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.

  2. 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.)

  3. Thermodynamics of Ion Pair of Magnesium Sulfate in Mixed Solvent

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Introduction Magnesium sulfate is an archetypal 2-2 salt that plays a central role in defining the characteristics of higher valent electrolyte solutions and its solution has been widely used to test various theories of strong electrolyte behavior and to develop models of ion association in solution[1]. Up to now, the ion pairs of magnesium sulfate in an aqueous solution have been widely investigated by using different experimental techniques, such as conductometry[2] , cryoscopy[3] , potentiometry[4] ,solubility[5] and Raman spectrometry[6]. However, to our knowledge, no measurement of the standard association constant of the ion pairs, [MgSO4] 0 in a glucosewater mixed solvent is available.

  4. 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.

  5. Improvement in corrosion resistance of magnesium coating with cerium treatment

    Institute of Scientific and Technical Information of China (English)

    Samia Ben Hassen; Latifa Bousselmi; Patricc Bercot; El Mustafa Rezrazi; Ezzeddine Triki

    2009-01-01

    Corrosion protection afforded by a magnesium coating treated in cerium salt solution on steel substrate was investigated using open circuit potential, polarization curves, and electrochemical impedance spectroscopy (EIS) in 0.005 M sodium chloride solution (NaCl). The morphology of the surface was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The cerium treated coating was obtained by immersion in CeCl3 solution. The results showed that the corrosion resistance of the treated magnesium coating was improved. The corrosion potential of the treated coating was found to be nobler than that of the untreated magnesium coating and the corrosion current decreased significantly. Impedance results showed that the cerium treatment increased corrosion protection. The improvement of anti-corrosion properties was ataibuted to the formation of cerium oxides and hydroxides that gave to a physical barrier effect.

  6. MICROSTRUCTURAL STUDIES OF FRICTION STIR WELDED AZ31 MAGNESIUM ALLOY

    Institute of Scientific and Technical Information of China (English)

    H.Zhang; S.B.Lin; L.Wu; J.C.Feng

    2004-01-01

    Friction stir welding achieves the weld in solid phase by locally introducing frictional heating and plastic flow arising from rotation of the welding tool, which results in changes in the local microstructure of magnesium alloy. The purpose in the paper is to study the microstructures of friction stir welded AZ3I magnesium alloy. Residual microstructures,including dynamic re-crystallization zone and nugget structures have been systematically investigated utilizing optical microscopy (OM), scanning electric microscopy (SEM),transmission electron microscopy (TEM) with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and micro-hardness. AZ31 magnesium alloy has been successfully friction stir welded and exhibits the variations of microstructure including dynamically recrystallized,equaxied grains in the weld nugget. Residual hardness in the nugget was found slightly lower than the parent but not too obvious.

  7. 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.

  8. 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

  9. 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....

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. A Review on biological and phytochemical investigation of plant genus Callistimon

    Institute of Scientific and Technical Information of China (English)

    Praveen Kumar Goyal; Renuka Jain; Shweta Jain; Archana Sharma

    2012-01-01

    Objective: The large flowering plant genus Callistemon is belongs to family Myrtaceae and reported for its medical importance. Various parts of different species exhibit different medicinal importance and yet to be phytochemically investigated. In the different time various scientist have investigated the genus and reported the chemical constituents. A survey of literature on genus Callistemon reported the isolation of triterpenoids and steroids from leaves, seeds and stem bark of different species.

  16. 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

  17. 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...

  18. Synthesis and Biological Investigation of Δ(12)-Prostaglandin J3 (Δ(12)-PGJ3) Analogues and Related Compounds.

    Science.gov (United States)

    Nicolaou, K C; Pulukuri, Kiran Kumar; Rigol, Stephan; Heretsch, Philipp; Yu, Ruocheng; Grove, Charles I; Hale, Christopher R H; ElMarrouni, Abdelatif; Fetz, Verena; Brönstrup, Mark; Aujay, Monette; Sandoval, Joseph; Gavrilyuk, Julia

    2016-05-25

    A series of Δ(12)-prostaglandin J3 (Δ(12)-PGJ3) analogues and derivatives were synthesized employing an array of synthetic strategies developed specifically to render them readily available for biological investigations. The synthesized compounds were evaluated for their cytotoxicity against a number of cancer cell lines, revealing nanomolar potencies for a number of them against certain cancer cell lines. Four analogues (2, 11, 21, and 27) demonstrated inhibition of nuclear export through a covalent addition at Cys528 of the export receptor Crm1. One of these compounds (i.e., 11) is currently under evaluation as a potential drug candidate for the treatment of certain types of cancer. These studies culminated in useful and path-pointing structure-activity relationships (SARs) that provide guidance for further improvements in the biological/pharmacological profiles of compounds within this class.

  19. Removal of Exogenous Materials from the Outer Portion of Frozen Cores to Investigate the Ancient Biological Communities Harbored Inside.

    Science.gov (United States)

    Barbato, Robyn A; Garcia-Reyero, Natàlia; Foley, Karen; Jones, Robert; Courville, Zoe; Douglas, Thomas; Perkins, Edward; Reynolds, Charles M

    2016-01-01

    The cryosphere offers access to preserved organisms that persisted under past environmental conditions. In fact, these frozen materials could reflect conditions over vast time periods and investigation of biological materials harbored inside could provide insight of ancient environments. To appropriately analyze these ecosystems and extract meaningful biological information from frozen soils and ice, proper collection and processing of the frozen samples is necessary. This is especially critical for microbial and DNA analyses since the communities present may be so uniquely different from modern ones. Here, a protocol is presented to successfully collect and decontaminate frozen cores. Both the absence of the colonies used to dope the outer surface and exogenous DNA suggest that we successfully decontaminated the frozen cores and that the microorganisms detected were from the material, rather than contamination from drilling or processing the cores. PMID:27403572

  20. Evaluation of magnesium ions release, biocorrosion, and hemocompatibility of MAO/PLLA-modified magnesium alloy WE42.

    Science.gov (United States)

    Lu, Ping; Cao, Lu; Liu, Yin; Xu, Xinhua; Wu, Xiangfeng

    2011-01-01

    Magnesium alloys may potentially be applied as biodegradable metallic materials in cardiovascular stent. However, the high corrosion rate hinders its clinical application. In this study, a new approach was adopted to control the corrosion rate by fabricating a biocompatible micro-arc oxidation/poly-L-lactic acid (MAO/PLLA) composite coating on the magnesium alloy WE42 substrate and the biocompatibility of the modified samples was investigated. The scanning electronic microscope (SEM) images were used to demonstrate the morphology of the samples before and after being submerged in hanks solution for 4 weeks. The degradation was evaluated through the magnesium ions release rate and electrochemical impedance spectroscopy (EIS) test. The biocompatibility of the samples was demonstrated by coagulation time and hemolysis behavior. The result shows that the poly-L-lactic acid (PLLA) effectively improved the corrosion resistance by sealing the microcracks and microholes on the surface of the MAO coating. The modified samples had good compatibility.

  1. 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.

  2. 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

  3. Effect of CaC2 particulates concentration on microstructure and tensile properties of elemental magnesium

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    CaC2 particulates reinforced magnesium materials were synthesized using a new technique--electromagnetic suspension casting(ESC).The microstructure and composition of magnesium alloys were investigated and the mechanical properties of alloys were tested.The tensile fracture surfaces were also studied by scanning electron microscopy.And the grain refinement effect of alloys was also examined.The results indicate that proper additions of CaC2 particulates are found to be efficient in refining the microstructure of magnesium materials.The tensile properties of alloys are consistent with the grain sizes.0.26%(mass fractionl of CaC2 addition reduces the mean grain size of pure magnesium from more than 2 mm to 125 μm,and the ultimate tensile strength of pure magnesium at room temperature decreases from 77 to 148 MPa.

  4. 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

  5. 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.

  6. Biomedical applications of magnesium alloys

    NARCIS (Netherlands)

    Sillekens, W.H.; Bormann, D.

    2012-01-01

    This chapter deals with the emerging field of biomedical applications for magnesium-based materials, envisioning degradable implants that dissolve in the human body after having cured a particular medical condition. After outlining the background of this interest, some major aspects concerning degra

  7. 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...

  8. Investigation of Marine-Derived Fungal Diversity and Their Exploitable Biological Activities.

    Science.gov (United States)

    Hong, Joo-Hyun; Jang, Seokyoon; Heo, Young Mok; Min, Mihee; Lee, Hwanhwi; Lee, Young Min; Lee, Hanbyul; Kim, Jae-Jin

    2015-07-01

    Marine fungi are potential producers of bioactive compounds that may have pharmacological and medicinal applications. Fungi were cultured from marine brown algae and identified using multiple target genes to confirm phylogenetic placement. These target genes included the internal transcribed spacer (ITS), the nuclear large subunit (LSU), and the β-tubulin region. Various biological activities of marine-derived fungi were evaluated, including their antifungal, antioxidant and cellulolytic enzyme activities. As a result, a total of 50 fungi was isolated from the brown algae Sargassum sp. Among the 50 isolated fungi, Corollospora angusta was the dominant species in this study. The genus Arthrinium showed a relatively strong antifungal activity to all of the target plant pathogenic fungi. In particular, Arthrinium saccharicola KUC21221 showed high radical scavenging activity and the highest activities in terms of filter paper units (0.39 U/mL), endoglucanase activity (0.38 U/mL), and β-glucosidase activity (1.04 U/mL). PMID:26133554

  9. 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)

  10. 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.

  11. 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.

  12. 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.

  13. Phytochemical and in vitro biological investigations of methanolic extracts of Enhydra fluctuans Lour

    Institute of Scientific and Technical Information of China (English)

    Sourov Kuri; Md Mustahsan Billah; S M Masud Rana; Zannatul Naim; Md Mahmodul Islam; Md Hasanuzzaman; Md Ramjan Ali; Rana Banik

    2014-01-01

    Objective: To study the phytochemical and biological properties (antioxidant, anthelmintic and thrombolytic) of methanolic extracts of Enhydra fluctuans Lour., a plant belonging to the Asteraceae family. Methods:The phytochemical evaluation was carried out by qualitative analysis. In vitro antioxidant activity of extract was studied using free radical scavenging assay, ability of reduction, total phenol and total flavonoid contents determination assays. The anthelmintic activity was determined using paralysis and death time of Pheretima posthuma (earthworm) and thrombolytic activity by clot disruption assay. Results:The phytochemical evaluation showed significant presence of flavonoids, triterpenes,carbohydrate, reducing sugars, saponins, phenols, diterpenes, protein and tannin. The antioxidant activity was found significant [IC50=(135.20±0.56) µg/mL] as compared to ascorbic acid [(130.00±0.76) µg/mL]. The reducing power was increased with concentration. Total phenol and total flavonoid contents were (153.08±0.38) mg/mL and (172.04±0.56) mg/mL respectively. The paralysis and death time of earthworms for different concentrations of extract were determined and compared with albendazole. The results showed that 10 mg/mL of the crude extract had similar effect with albendazole. Additionally, the crude extract showed a concentration depended relationship with its anthelmintic property. The clot lysis activity of crude extract was compared to the standard streptokinase’s clot lysis (40.13%) activity and found significant (31%). Conclusions: The study proves that the crude methanolic extract of Enhydra fluctuans Lour. has significant antioxidant, anthelmintic and thrombolytic activity containing wide range of phytochemicals.

  14. 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.

  15. [Novel concepts in biology of diffuse endocrine system: results and future investigations].

    Science.gov (United States)

    Iaglov, V V; Iaglova, N V

    2012-01-01

    Diffuse endocrine system is a largest part of endocrine system of vertebrates. Recend findings showed that DES-cells are not neuroectodermal but have ectodermal, mesodermal, and entodermal ontogeny. The article reviews novel concept of diffuse endocrine system anatomy and physiology, functional role of DES hormones and poorly investigated aspects like DES-cell morphology, hormones secretion in normal and pathologic conditions. Further research of diffuse endocrine system has a great significance for biochemistry, morphology, and clinical medicine.

  16. 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

  17. 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 Tfat globules during processing and digestion.

  18. 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)

  19. 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.

  20. 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)

  1. 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.

  2. Investigation of the biological roles of autophagy in appressorium morphogenesis in Magnaporthe oryzae

    Institute of Scientific and Technical Information of China (English)

    Xiao-hong LIU; Fu-cheng LIN

    2008-01-01

    Magnaporthe oryzae has been used as a primary model organism for investigating fungus-plant interaction. Many researches focused on molecular mechanisms of appressorium formation to restrain this fungal pathogen. Autophagy is a very high conserved process in eukaryotic cells. Recently, autophagy has been considered as a key process in development and differentiation in M. oryzae. In this report, we present and discuss the current state of our knowledge on gene expression in appressorium formation and the progress in autophagy of rice blast fungi.

  3. Biological applications and spectroscopic investigations of 4-nitrophenol-urea dimer: A DFT approach

    Science.gov (United States)

    Beaula, T. Joselin; Muthuraja, P.; Dhandapani, M.; Joe, I. Hubert; Rastogi, V. K.; Jothy, V. Bena

    2016-02-01

    Molecular geometry of grown crystal 4-nitrophenol-urea has been evaluated and compared with XRD data while the crystalline nature of the compound has been confirmed by PXRD study. Vibrational analysis has been performed using NCA and dielectric studies have been carried out at room temperature. NBO analysis has been applied in comparative study of charge delocalization. Molecular orbital contributions have been investigated by TDOS and αβDOS. Enhancement of microbial treatments against bacteria and fungi has been assessed and a remarkable efficiency has been recorded.

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

    Directory of Open Access Journals (Sweden)

    Zhiping Wu

    2014-01-01

    Full Text Available 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 tensile properties of UMH/WPC are superior to that of WPC and OMH/WPC. The limited oxygen index (LOI and cone calorimeter test illustrated that ultrafine magnesium hydroxide has stronger flame retardancy and smoke suppression effect of WPC compared to that of ordinary magnesium hydroxide. The results of thermogravimetric analysis implied that ultrafine magnesium hydroxide can improve the char structure which plays an important role in reducing the degradation speed of the inner matrix during combustion process and increases the char residue at high temperature.

  5. 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

  6. 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.

  7. 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...

  8. 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.

  9. 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

  10. [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

  11. Investigation of biologically-designed metal-specific chelators for potential metal recovery and waste remediation applications.

    Energy Technology Data Exchange (ETDEWEB)

    Criscenti, Louise Jacqueline; Ockwig, Nathan W.

    2009-01-01

    Bacteria, algae and plants produce metal-specific chelators to capture required nutrient or toxic trace metals. Biological systems are thought to be very efficient, honed by evolutionary forces over time. Understanding the approaches used by living organisms to select for specific metals in the environment may lead to design of cheaper and more effective approaches for metal recovery and contaminant-metal remediation. In this study, the binding of a common siderophore, desferrioxamine B (DFO-B), to three aqueous metal cations, Fe(II), Fe(III), and UO{sub 2}(VI) was investigated using classical molecular dynamics. DFO-B has three acetohydroxamate groups and a terminal amine group that all deprotonate with increasing pH. For all three metals, complexes with DFO-B (-2) are the most stable and favored under alkaline conditions. Under more acidic conditions, the metal-DFO complexes involve chelation with both acetohydroxamate and acetylamine groups. The approach taken here allows for detailed investigation of metal binding to biologically-designed organic ligands.

  12. 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

  13. 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

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

    Science.gov (United States)

    Momtaz, Saeideh; Lall, Namrita; Hussein, Ahmed; Ostad, Seyed Nasser; Abdollahi, Mohammad

    2010-01-01

    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 (IC50) 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

  15. 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.

  16. 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)

  17. 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.

  18. 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

  19. Solid state cathode materials for secondary magnesium-ion batteries that are compatible with magnesium metal anodes in water-free electrolyte

    Science.gov (United States)

    Crowe, Adam J.; Bartlett, Bart M.

    2016-10-01

    With high elemental abundance, large volumetric capacity, and dendrite-free metal deposition, magnesium metal anodes offer promise in beyond-lithium-ion batteries. However, the increased charge density associated with the divalent magnesium-ion (Mg2+), relative to lithium-ion (Li+) hinders the ion-insertion and extraction processes within many materials and structures known for lithium-ion cathodes. As a result, many recent investigations incorporate known amounts of water within the electrolyte to provide temporary solvation of the Mg2+, improving diffusion kinetics. Unfortunately with the addition of water, compatibility with magnesium metal anodes disappears due to forming an ion-insulating passivating layer. In this short review, recent advances in solid state cathode materials for rechargeable magnesium-ion batteries are highlighted, with a focus on cathode materials that do not require water contaminated electrolyte solutions for ion insertion and extraction processes.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  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. The influence of lithium on calcium and magnesium homeostasis in serum and tissues of rats.

    Science.gov (United States)

    Kiełczykowska, Małgorzata; Pasternak, Kazimierz; Musik, Irena

    2003-01-01

    Lithium is used in medicine. However, its administration can have negative side effects, disturb the water-electrolyte equilibrium and affect the level of essential elements. For these reasons the influence of oral lithium intoxication at the dose of 150 mg Li dm(-3) on magnesium and calcium levels in serum and tissues of rats was investigated. The concentration of Mg and Ca in serum increased throughout the experiment. The concentration of magnesium in tissues decreased after three weeks in liver, kidney, brain and femoral muscle. The trend of the changes of calcium tissue concentration was opposite to the one observed in the case of magnesium.

  7. 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...

  8. 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...

  9. 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

    ... aware used to make such excluded reagents are: lime, calcium metal, calcium silicon, calcium carbide...: 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...

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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

  17. Sodium picosulfate/magnesium citrate: a review of its use as a colorectal cleanser.

    Science.gov (United States)

    Hoy, Sheridan M; Scott, Lesley J; Wagstaff, Antona J

    2009-01-01

    from that recommended. In children and adolescents, sodium picosulfate/magnesium citrate was significantly more effective as a colorectal cleansing agent than oral bisacodyl 0.01 or 0.02 g plus a sodium phosphate enema preparation in a randomized, single-blind study; dosages were adjusted for age in this study. Oral sodium picosulfate/magnesium citrate is generally well tolerated in adult patients undergoing various investigational colorectal procedures. Adverse events were generally mild to moderate in intensity and mainly gastrointestinal in nature (e.g. abdominal cramps/pain, nausea); other common treatment-emergent adverse events included disturbance of daily activity, headache and sleep disturbance. This combination is at least as well tolerated as oral sodium phosphate or oral polyethylene glycol, with moderate/severe nausea and vomiting occurring less frequently in sodium picosulfate/magnesium citrate recipients than in those receiving oral sodium phosphate, and abdominal bloating/pain and nausea developing less often with sodium picosulfate/magnesium citrate than polyethylene glycol therapy. The incidence of abdominal pain and sleep disturbance in sodium picosulfate/magnesium citrate versus oral magnesium citrate recipients was similar in one study, but significantly lower with sodium picosulfate/magnesium citrate in another. While the incidence of most adverse events was similar in recipients of sodium picosulfate/magnesium citrate and a sodium phosphate enema preparation, more patients receiving sodium picosulfate/magnesium citrate reported moderate/severe flatulence, incontinence and sleep disturbance, and more patients receiving the enema preparation reported rectal soreness. The tolerability profile of sodium picosulfate/magnesium citrate in patients aged >70 years is reportedly similar to that in patients aged sodium picosulfate/magnesium citrate than with oral bisacodyl plus a sodium phosphate enema preparation in children and adolescents.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. [Magnesium deficiency and stress: Issues of their relationship, diagnostic tests, and approaches to therapy].

    Science.gov (United States)

    Tarasov, E A; Blinov, D V; Zimovina, U V; Sandakova, E A

    2015-01-01

    Magnesium plays an important role in the functions of the central nervous system. It takes part in the regulation of the cell membrane, the transmembrane transport of calcium and sodium ions, and metabolic reactions that produce, accumulate, transfer, and utilize energy, free radicals, and their oxidation products. The magnesium-containing substances include many sequestered antigens, such as glial fibrillary acidic protein, S100, and neuron-specific enolase; magnesium may act as a neuroprotector that is able to modulate the regulation of blood-brain barrier permeability. Investigations have demonstrated a relationship between the manifestations of stress reactions (anxiety, autonomic dysfunction, and maladjustment) and magnesium deficiency (MD). Thus, mental and physical stresses cause an increase in magnesium elimination from the body. MD in turn enhances a response to stress, by paradoxically aggravating its sequels. Compensation for MD increases the ability of the nervous system to resist stress. The valid diagnosis of MD present difficulties; namely, a blood magnesium concentration decrease below 0.8 mmol/l is evidence of MD; but the constant blood level of magnesium may be long maintained due to its release from the bone tissue depot. So it is necessary to keep in mind the clinical manifestations of MD. The authors have developed and tested a simple rapid MD assessment test and a stress resistance self-rating test. The proposed tests will help to screen stress resistance and MD in outpatient settings.

  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. 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

    2014-12-28

    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.

  5. 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.

  6. Preparation of perlite-based magnesium perchlorate desiccant with colour indicator.

    Science.gov (United States)

    Wu, L; He, H

    1994-05-01

    A new desiccant consisting of magnesium perchlorate, expanded perlite and metal chelate was prepared. The performance tests show that the desiccant is superior to magnesium perchlorate desiccant in dehydration efficiency, absorption capacity for water, flow resistance, color indicator and regeneration. It can reduce the amount of water in gases to approximately 0.7 ppm(v/v). Its applications in gas analysis and purification were investigated.

  7. 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...

  8. 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...

  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. 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 ...

  11. 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...

  12. 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.;

    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....

  13. 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.

  14. 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.

  15. 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.

  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. Effect of fabrication and processing technology on the biodegradability of magnesium nanocomposites.

    Science.gov (United States)

    Ma, Chao; Chen, Lianyi; Xu, Jiaquan; Fehrenbacher, Axel; Li, Yan; Pfefferkorn, Frank E; Duffie, Neil A; Zheng, Jing; Li, Xiaochun

    2013-07-01

    Magnesium and its alloys have gained significant attention recently as potential alternatives for biodegradable materials due to their unique biodegradability, biocompatibility, and mechanical properties. However, magnesium alloys tend to have high corrosion rates in biological liquids, thus presenting a potential problem if a magnesium implant/device needs to maintain mechanical integrity for a sufficient period under practical physiological conditions. In this study, hydroxyapatite nanoparticles were used to form magnesium based metal matrix nanocomposites (MMNC) through two processes: friction stir processing (FSP) and a two-state nanoprocessing (TSnP) combining liquid state ultrasonic processing and solid state FSP. In addition, laser surface melting (LSM) was carried out for further surface treatment. In vitro immersion tests indicated that the corrosion rate of MMNC decreased by 52% compared with pure Mg through FSP. Potentiodynamic polarization tests showed that the corrosion current of MMNC decreased by 71% and 30%, respectively, by TSnP and LSM when compared with pure Mg or untreated counterparts. This study suggests that fabrication of MMNC and further processing through FSP and LSM can robustly enhance the corrosion resistance of magnesium, which will boost its potential for biological applications.

  18. 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.

  19. Investigation of decolorization of textile wastewater in an anaerobic/aerobic biological activated carbon system (A/A BAC).

    Science.gov (United States)

    Pasukphun, N; Vinitnantharat, S; Gheewala, S

    2010-04-01

    The aim of this study is to investigate the decolorization in anaerobic/aerobic biological activated carbon (A/A BAC) system. The experiment was divided into 2 stages; stage I is batch test for preliminary study of dye removal equilibrium time. The preliminary experiment (stage I) provided the optimal data for experimental design of A/A BAC system in SBR (stage II). Stage II is A/A BAC system imitated Sequencing Batch Reactor (SBR) which consist of 5 main periods; fill, react, settle, draw and idle. React period include anaerobic phase followed by aerobic phase. The BAC main media; Granular Activated Carbon (GAC), Mixed Cultures (MC) and Biological Activated Carbon (BAC) were used for dye and organic substances removal in three different solutions; Desizing Agent Solution (DAS), dye Solution (DS) and Synthetic Textile Wastewater (STW). Results indicate that GAC adsorption plays role in dye removal followed by BAC and MC activities, respectively. In the presence desizing agent, decolorization by MC was improved because desizing agent acts as co-substrates for microorganisms. It was found that 50% of dye removal efficiency was achieved in Fill period by MC. GC/MS analysis was used to identify dye intermediate from decolorization. Dye intermediate containing amine group was found in the solution and on BAC surfaces. The results demonstrated that combination of MC and BAC in the system promotes decolorization and dye intermediate removal. In order to improve dye removal efficiency in an A/A BAC system, replacement of virgin GAC, sufficient co-substrates supply and the appropriate anaerobic: aerobic period should be considered.

  20. 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.

  1. 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.

  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. 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

  4. 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.

  5. 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; ZHOU Yang

    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.

  6. 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...

  7. 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...

  8. 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...

  9. New perspective in the assessment of total intracellular magnesium

    Directory of Open Access Journals (Sweden)

    Azzurra Sargenti

    2014-01-01

    Full Text Available Magnesium (Mg is essential for biological processes, but its cellular homeostasis has not been thoroughly elucidated, mainly because of the inadequacy of the available techniques to map intracellular Mg distribution. Recently, particular interest has been raised by a new family of fluorescent probes, diaza-18-crown-hydroxyquinoline (DCHQ, that shows remarkably high affinity and specificity for Mg, thus permitting the detection of the total intracellular Mg. The data obtained by fluori- metric and cytofluorimetric assays performed with DCHQ5 are in good agreement with atomic absorption spectroscopy, confirming that DCHQ5 probe allows both qualitative and quantitative determination of total intracellular Mg.

  10. 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

  11. 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.

  12. 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.

  13. Ionic conductance behavior of polymeric gel electrolyte containing ionic liquid mixed with magnesium salt

    Science.gov (United States)

    Morita, Masayuki; Shirai, Takahiro; Yoshimoto, Nobuko; Ishikawa, Masashi

    A new polymeric gel electrolyte system conducting magnesium ion has been proposed. The gel electrolytes consisted of poly(ethylene oxide)-modified polymethacrylate (PEO-PMA) dissolving ionic liquid mixed with magnesium salt, Mg[(CF 3SO 2) 2N] 2. The polymeric gel films were self-standing, transparent and flexible with enough mechanical strength. The ionic conductance and the electrochemical properties of the gel films were investigated. Thermal analysis results showed that the polymeric gel is homogeneous and amorphous over a wide temperature range. The highest conductivity, 1.1 × 10 -4 S cm -1 at room temperature (20 °C), was obtained for the polymeric gel containing 50 wt.% of the ionic liquid in which the content of the magnesium salt was 20 mol%. The dc polarization of a Pt/Mg cell using the polymeric gel electrolyte proved that the magnesium ion (Mg 2+) is mobile in the present polymeric system.

  14. 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.

  15. 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.

  16. 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.

  17. Effects of production parameters on characteristics of magnesium alloy sheets manufactured by twin-roll casting

    Directory of Open Access Journals (Sweden)

    H. Watari

    2006-04-01

    Full Text Available Purpose: : The purpose of the work is to establish a manufacturing process and technology to facilitate the economical manufacture of high-quality magnesium sheet alloys.Design/methodology/approach: Magnesium alloy AZ31B was used to investigate the appropriate manufacturing conditions for use in twin-roll strip casting. Temperatures of the molten materials and roll speeds were varied to find the appropriate manufacturing conditions. The effects of manufacturing conditions on possible forming were clarified in terms of roll speeds and roll gaps between upper and lower rolls.Findings: In the hot-rolling process, a temperature exceeding 200°C was chosen to keep cast products from cracking. An appropriate annealing temperature was effective for homogenizing the microstructure of the rolled cast sheets after the strip casting process. The grain size of the manufactured wrought magnesium alloys sheet was less than 10 micrometers. The obtained magnesium alloy sheet exhibited an equivalent limiting drawing ratio in a warm-drawing test.Research limitations/implications: AZ31 were used to investigate the appropriate manufacturing conditions for use in twin-roll strip casting. Casting temperatures were varied from 630°C to 670°C to find the best casting conditions. Roll casting speeds were varied from 5m/min to 30 m/min in order to examine which roll speed was appropriate for solidifying the molten magnesium.Practical implications: It was found that the cast magnesium sheet manufactured by roll strip casting could be used for plastic forming if the appropriate magnesium sheets were produced after the roll casting process.Originality/value: This paper showed the effectiveness of twin roll casting for magnesium alloys by a horizontal roll caster.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Investigation of role of silver nanoparticles on spectroscopic properties of biologically active coumarin dyes 4PTMBC and 1IPMBC.

    Science.gov (United States)

    Raghavendra, U P; Basanagouda, Mahantesha; Thipperudrappa, J

    2015-01-01

    The role of silver nanoparticles on spectroscopic properties of biologically active coumarin dyes 4-p-tolyloxymethyl-benzo[h]coumarin (4PTMBC) and 1-(4-iodophenoxymethyl)-benzo[f]coumarin (1IPMBC) has been investigated using absorption and fluorescence spectroscopy. Silver nanoparticles are synthesized by chemical reduction method and the estimated size by Mie theory is 12 nm. The absorption spectral changes of dyes in the presence of silver nanoparticles suggest their possible interaction with silver nanoparticles. The apparent association constants of the interaction are estimated using Benesi-Hildebrand model. Fluorescence quenching has been observed in both the dyes with the addition of silver nanoparticles. The Stern-Volmer plots of fluorescence quenching are found to be nonlinear showing positive deviation. The magnitudes of quenching rate parameter and fluorescence lifetime measurements indicate the presence of both collisional and static quenching mechanisms. The binding constants and the number of binding sites for the static type of quenching have been estimated from the fluorescence data. The role of diffusion, energy transfer and electron transfer processes in fluorescence quenching mechanism has been discussed.

  3. 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

  4. 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.

  5. A Simple and Low-Cost Monitoring System to Investigate Environmental Conditions in a Biological Research Laboratory.

    Directory of Open Access Journals (Sweden)

    Akshay Gurdita

    Full Text Available 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.

  6. 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...

  7. The association between serum 25-hydroxyvitamin D3 concentration and risk of disease death in men: modification by magnesium intake.

    Science.gov (United States)

    Mursu, Jaakko; Nurmi, Tarja; Voutilainen, Sari; Tuomainen, Tomi-Pekka; Virtanen, Jyrki K

    2015-04-01

    Low vitamin D status increases the risk of death. Magnesium plays an essential role in vitamin D metabolism and low magnesium intake may predispose to vitamin D deficiency and potentiate the health problems. We investigated whether magnesium intake modifies the serum 25(OH)D3 concentration and its associations with mortality in middle-aged and older men. We included 1892 men aged 42-60 years without cardiovascular disease or cancer at baseline in 1984-1989 from the prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor Study. Serum 25(OH)D3 was measured with the high-performance liquid chromatography using coulometric electrode array detection. Magnesium intake was assessed with 4-day food recording. Deaths were ascertained by a computer linkage to the national cause of death register. Deaths due accidents and suicides were excluded. Cox proportional hazards regression models were used to analyze the associations. The multivariate-adjusted hazard ratio (HR) for death in the lowest (49.4 nmol/L) serum 25(OH)D3 tertile was 1.31 (95 % CI 1.07-1.60, Ptrend = 0.01). Stratified by the magnesium intake, the higher risk was observed only in the lower magnesium intake median (magnesium intake median, P for interaction = 0.08. In this cohort of middle-aged and older men low serum 25(OH)D3 concentration was associated with increased risk of death mainly in those with lower magnesium intake.

  8. 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

  9. Precision forging technologies for magnesium alloy bracket and wheel

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Fundamental investigations on precision forging technology of magnesium alloys were studied. As-cast billet prestraining and a new concept of hollow billet were proposed in order to reduce the maximum forming load. A scheme of isothermal forming and the use of combined female dies were adopted, which can improve the die filling capacity and ensure the manufacture of high quality forgings. By means of the developed technique, AZ80 alloy wheel and AZ31 alloy bracket were produced successfully at suitable process parameters and applied in the automotive industries. The results show that the hot compression of AZ80 magnesium alloy has the peak flow stresses of pre-strained alloy with finer grain, which are lower by 20% than those of as-cast alloy under the same deformation conditions. The forming load is related to contact area and average positive stress on interface during forging process.

  10. 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.

  11. Friction stir welding of AZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    林三宝; 张华; 吴林; 冯吉才; 戴鸿滨

    2003-01-01

    Friction stir welding (FSW) is an new solid-phase joining technology which has more advantages over fusion welding methods in welding of aluminum and other non-ferrous metals. The effects of welding parameters on mechanical properties and microstructure during friction stir welding of AZ31 magnesium alloy were studied in this paper. Microstructures and mechanical properties of the joints were investigated by means of optical microscopy, scanning electric microscopy (SEM), micro-hardness analysis, and tensile test. Experimental results show that the magnesium alloy can be successfully welded by FSW method, and the ultimate tensile strength (UTS) of FSW joint reaches up to 90 percent of base metal. The microstructures of welded joints exhibit the variation from dynamically recrystallized fine grains to greatly deformed grains. Hardness in nugget zone was found lower than the base metal but not too obvious.

  12. 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.

  13. Microstructure analysis of magnesium alloy melted by laser irradiation

    Science.gov (United States)

    Liu, S. Y.; Hu, J. D.; Yang, Y.; Guo, Z. X.; Wang, H. Y.

    2005-12-01

    The effects of laser surface melting (LSM) on microstructure of magnesium alloy containing Al8.57%, Zn 0.68%, Mn0.15%, Ce0.52% were investigated. In the present work, a pulsed Nd:YAG laser was used to melt and rapidly solidify the surface of the magnesium alloy with the objective of changing microstructure and improving the corrosion resistance. The results indicate that laser-melted layer contains the finer dendrites and behaviors good resistance corrosion compared with the untreated layer. Furthermore, the absorption coefficient of the magnesium alloy has been estimated according to the numeral simulation of the thermal conditions. The formation process of fine microstructure in melted layers was investigated based on the experimental observation and the theoretical analysis. Some simulation results such as the re-solidification velocities are obtained. The phase constitutions of the melted layers determined by X-ray diffraction were β-Mg 17Al 12 and α-Mg as well as some phases unidentified.

  14. 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.

  15. 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

  16. Magnesium and disturbances in carbohydrate metabolism.

    Science.gov (United States)

    Mooren, Frank C

    2015-09-01

    Magnesium is actively involved in a number of metabolic reactions as an important co-factor, with special emphasis on carbohydrate metabolism. After a brief overview of the regulation of intra- and extracellular magnesium, the present review first describes the regulatory role of magnesium in important metabolic pathways involved in energy metabolism and glycaemic control. Next the clinical significance of hypomagnesaemic conditions with regard to the management of glucose in prediabetic stages, such as insulin resistance/impaired glucose tolerance and in type 2 diabetes mellitus are characterized. Cross-sectional as well as longitudinal studies suggest that a reduced dietary magnesium intake serves as a risk factor for the incidence of both impaired glucose regulation and type 2 diabetes. Mechanisms that might be responsible for diabetes-associated hypomagnesaemia are discussed. Furthermore, the role of hypomagnesaemia in the development and progression of chronic diabetic complications are addressed. Finally, the available literature on the effects of magnesium supplementation on glycaemic control parameters during prediabetic conditions (preventive approach) as well as type 2 diabetes mellitus (therapeutic approach) are reviewed systematically. There is considerable evidence that chronic magnesium supplementation may delay the progression from impaired glucose regulation to type 2 diabetes; however, the effects of oral magnesium supplementation as an adjunct therapy for type 2 diabetes are quite heterogeneous with respect to the various measures of glycaemic control. The results of this review suggest a requirement for critical consideration of the pros and cons of magnesium replacement therapy, based on variables such as magnesium status, stage of disease and glycaemic control.

  17. 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....

  18. 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.

  19. 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....

  20. 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.

  1. (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)

  2. 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.

  3. 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

  4. 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.

  5. Dietary magnesium intake and risk of cancer: a meta-analysis of epidemiologic studies.

    Science.gov (United States)

    Ko, Hae Jin; Youn, Chang Ho; Kim, Hyo Min; Cho, Yoon Jeong; Lee, Geon Ho; Lee, Won Kee

    2014-01-01

    The aim of this study was to investigate the association between dietary magnesium and the risk of overall cancer using a meta-analysis. We searched PubMed, SCOPUS, and the Cochrane Review through November 2012. All the articles searched were independently reviewed by 3 authors based on predetermined selection criterion. A total of 13 epidemiologic studies, 6 case-control studies, and 7 prospective cohort studies involving 1,236,004 participants were included in the final analysis. When all studies were pooled, the relative risk (RR) of overall cancer for the highest level of dietary magnesium intake was 0.801 [95% confidence interval (CI): 0.664-0.966) compared with the lowest level of dietary magnesium intake. In subgroup meta-analyses by study design, there was a significant inverse association between dietary magnesium and the risk of cancer in case-control studies (RR = 0.663, 95% CI: 0.475-0.925), whereas there was no significant association in prospective cohort studies (RR = 0.888, 95% CI: 0.745-1.060). Furthermore, there was a significant preventive effect of dietary magnesium for colorectal cancer (RR = 0.775, 95% CI: 0.655-0.919), but not for other cancer. Our meta-analysis showed that higher dietary magnesium intake seems to have a protective effect for cancer, especially colorectal cancer and in females.

  6. 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.

  7. 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.

  8. 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

  9. Systems Biology-Based Investigation of Cellular Antiviral Drug Targets Identified by Gene-Trap Insertional Mutagenesis.

    Science.gov (United States)

    Cheng, Feixiong; Murray, James L; Zhao, Junfei; Sheng, Jinsong; Zhao, Zhongming; Rubin, Donald H

    2016-09-01

    Viruses require host cellular factors for successful replication. A comprehensive systems-level investigation of the virus-host interactome is critical for understanding the roles of host factors with the end goal of discovering new druggable antiviral targets. Gene-trap insertional mutagenesis is a high-throughput forward genetics approach to randomly disrupt (trap) host genes and discover host genes that are essential for viral replication, but not for host cell survival. In this study, we used libraries of randomly mutagenized cells to discover cellular genes that are essential for the replication of 10 distinct cytotoxic mammalian viruses, 1 gram-negative bacterium, and 5 toxins. We herein reported 712 candidate cellular genes, characterizing distinct topological network and evolutionary signatures, and occupying central hubs in the human interactome. Cell cycle phase-specific network analysis showed that host cell cycle programs played critical roles during viral replication (e.g. MYC and TAF4 regulating G0/1 phase). Moreover, the viral perturbation of host cellular networks reflected disease etiology in that host genes (e.g. CTCF, RHOA, and CDKN1B) identified were frequently essential and significantly associated with Mendelian and orphan diseases, or somatic mutations in cancer. Computational drug repositioning framework via incorporating drug-gene signatures from the Connectivity Map into the virus-host interactome identified 110 putative druggable antiviral targets and prioritized several existing drugs (e.g. ajmaline) that may be potential for antiviral indication (e.g. anti-Ebola). In summary, this work provides a powerful methodology with a tight integration of gene-trap insertional mutagenesis testing and systems biology to identify new antiviral targets and drugs for the development of broadly acting and targeted clinical antiviral therapeutics. PMID:27632082

  10. Systems Biology-Based Investigation of Cellular Antiviral Drug Targets Identified by Gene-Trap Insertional Mutagenesis

    Science.gov (United States)

    Zhao, Junfei; Sheng, Jinsong; Rubin, Donald H.

    2016-01-01

    Viruses require host cellular factors for successful replication. A comprehensive systems-level investigation of the virus-host interactome is critical for understanding the roles of host factors with the end goal of discovering new druggable antiviral targets. Gene-trap insertional mutagenesis is a high-throughput forward genetics approach to randomly disrupt (trap) host genes and discover host genes that are essential for viral replication, but not for host cell survival. In this study, we used libraries of randomly mutagenized cells to discover cellular genes that are essential for the replication of 10 distinct cytotoxic mammalian viruses, 1 gram-negative bacterium, and 5 toxins. We herein reported 712 candidate cellular genes, characterizing distinct topological network and evolutionary signatures, and occupying central hubs in the human interactome. Cell cycle phase-specific network analysis showed that host cell cycle programs played critical roles during viral replication (e.g. MYC and TAF4 regulating G0/1 phase). Moreover, the viral perturbation of host cellular networks reflected disease etiology in that host genes (e.g. CTCF, RHOA, and CDKN1B) identified were frequently essential and significantly associated with Mendelian and orphan diseases, or somatic mutations in cancer. Computational drug repositioning framework via incorporating drug-gene signatures from the Connectivity Map into the virus-host interactome identified 110 putative druggable antiviral targets and prioritized several existing drugs (e.g. ajmaline) that may be potential for antiviral indication (e.g. anti-Ebola). In summary, this work provides a powerful methodology with a tight integration of gene-trap insertional mutagenesis testing and systems biology to identify new antiviral targets and drugs for the development of broadly acting and targeted clinical antiviral therapeutics. PMID:27632082

  11. 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.

  12. 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...

  13. 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

  14. 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...

  15. Magnesium Alloy for Repair of Lateral Tibial Plateau Defect in Minipig Model

    Institute of Scientific and Technical Information of China (English)

    Qiang Zhang; Xiao Lin; Zhengrong Qi; Lili Tan; Ke Yang; Zhuangqi Hu; Yan Wang

    2013-01-01

    Bone graft substitutes are widely-studied as alternatives to bone grafts in the clinic.The currently available products are mostly ceramics and polymers.Considerable progress has been made in the study of the biodegradable magnesium alloys,which possess the necessary attributions of a suitable substitute,including an excellent mechanical property.In the present study,a minipig model of a lateral tibial plateau defect was used to evaluate the effectiveness of a magnesium alloy in the repair of a critical-sized defect.The micro-arc oxidation (MAO)-coated ZK60 alloy tablets and medical-grade calcium sulfate pellets were used as the test and control materials,respectively.Bone morphology was monitored by computed tomography after the implantation for 2 and 4 months.It was found that the bone morphology in minipigs following magnesium treatment was similar to that of the normal bone,whereas an abnormal and concave morphology was displayed following the calcium sulfate treatment.The average bone healing rate for the magnesium-treated defects was higher than that of the calcium sulfate-treated defects at the first 4 months following the implantation.Overall,magnesium treatment appeared to improve the defect repair as compared with the calcium sulfate treatment.Thus,the MAO-coated ZK60 alloy appears to be a useful biocompatible bone graft substitute,and further research on its biological activity in vivo is needed.

  16. 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.

  17. 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.

  18. 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

  19. Buffer-regulated biocorrosion of pure magnesium.

    Science.gov (United States)

    Kirkland, Nicholas T; Waterman, Jay; Birbilis, Nick; Dias, George; Woodfield, Tim B F; Hartshorn, Richard M; Staiger, Mark P

    2012-02-01

    Magnesium (Mg) alloys are being actively investigated as potential load-bearing orthopaedic implant materials due to their biodegradability in vivo. With Mg biomaterials at an early stage in their development, the screening of alloy compositions for their biodegradation rate, and hence biocompatibility, is reliant on cost-effective in vitro methods. The use of a buffer to control pH during in vitro biodegradation is recognised as critically important as this seeks to mimic pH control as it occurs naturally in vivo. The two different types of in vitro buffer system available are based on either (i) zwitterionic organic compounds or (ii) carbonate buffers within a partial-CO(2) atmosphere. This study investigated the influence of the buffering system itself on the in vitro corrosion of Mg. It was found that the less realistic zwitterion-based buffer did not form the same corrosion layers as the carbonate buffer, and was potentially affecting the behaviour of the hydrated oxide layer that forms on Mg in all aqueous environments. Consequently it was recommended that Mg in vitro experiments use the more biorealistic carbonate buffering system when possible.

  20. 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

  1. 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.

  2. Dietary intake of magnesium may modulate depression.

    Science.gov (United States)

    Yary, Teymoor; Aazami, Sanaz; Soleimannejad, Kourosh

    2013-03-01

    Depressive symptoms are frequent in students and may lead to countless problems. Several hypotheses associate magnesium with depression because of the presence of this mineral in several enzymes, hormones, and neurotransmitters, which may play a key role in the pathological pathways of depression. The aim of this study was to assess whether magnesium intake could modulate depressive symptoms. A cross-sectional study was conducted on a convenience sample of 402 Iranian postgraduate students studying in Malaysia to assess the relationship between magnesium intake and depressive symptoms. The mean age of the participants was 32.54 ± 6.22 years. The results of the study demonstrated an inverse relationship between magnesium intake and depressive symptoms, which persisted even after adjustments for sex, age, body mass index, monthly expenses, close friends, living on campus, smoking (current and former), education, physical activity, and marital status.

  3. Antidepressant-like activity of magnesium in the chronic mild stress model in rats: alterations in the NMDA receptor subunits.

    Science.gov (United States)

    Pochwat, Bartłomiej; Szewczyk, Bernadeta; Sowa-Kucma, Magdalena; Siwek, Agata; Doboszewska, Urszula; Piekoszewski, Wojciech; Gruca, Piotr; Papp, Mariusz; Nowak, Gabriel

    2014-03-01

    Recent data suggests that the glutamatergic system is involved in the pathophysiology and treatment of major depressive disorder (MDD) and that the N-methyl-D-aspartate (NMDA) receptor is a potential target for antidepressant drugs. The magnesium ion blocks the ion channel of the NMDA receptor and prevents its excessive activation. Some preclinical and clinical evidence suggests also that magnesium may be useful in the treatment of depression. The present study investigated the effect of magnesium treatment (10, 15 and 20 mg/kg, given as magnesium hydroaspartate) in the chronic mild stress (CMS) model of depression in rats. Moreover, the effect of CMS and magnesium (with an effective dose) on the level of the proteins related to the glutamatergic system (GluN1, GluN2A, GluN2B and PSD-95) in the hippocampus, prefrontal cortex (PFC) and amygdala were examined. A significant reduction in the sucrose intake induced by CMS was increased by magnesium treatment at a dose of 15 mg/kg, beginning from the third week of administration. Magnesium did not affect this behavioural parameter in the control animals. CMS significantly increased the level of the GluN1 subunit in the amygdala (by 174%) and GluN2A in the hippocampus (by 191%), both of which were significantly attenuated by magnesium treatment. Moreover, magnesium treatment in CMS animals increased the level of GluN2B (by 116%) and PSD-95 (by 150%) in the PFC. The present results for the first time demonstrate the antidepressant-like activity of magnesium in the animal model of anhedonia (CMS), thus indicating the possible involvement of the NMDA/glutamatergic receptors in this activity.

  4. 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

  5. Nanostructured magnesium oxide as cure activator for polychloroprene rubber.

    Science.gov (United States)

    Kar, Sritama; Bhowmick, Anil K

    2009-05-01

    The aim of this research was to synthesize magnesium oxide nanoparticles and to use them as cure activator for polychloroprene rubber (CR). The effects of counterions of magnesium salts on the homogeneous phase precipitation reaction to control size, monodispersity, crystallinity, and morphology of Mg(OH)2 nanoparticles were also investigated. Magnesium oxide nanoparticles were synthesized by optimizing the calcination temperature of Mg(OH)2 nanoparticles. Finally, the MgO nanoparticles were dispersed in polychloroprene rubber (CR) solution along with zinc oxide (ZnO) powder. The influence of MgO nanoparticles on the mechanical, dynamic mechanical and thermal properties of the resulting nanocomposites was quantified. The modulus and strength of ZnO-cured polychloroprene rubber with 4% MgO nanoparticles appeared to be superior to those with ZnO particles or ZnO with rubber grade MgO particles. These composites were further characterized by transmission electron microscopy and infrared spectroscopy in order to understand the morphology of the resulting system and the load transfer mechanism. PMID:19452982

  6. 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

  7. Improving fundamental abilities of atomic force microscopy for investigating quantitative nanoscale physical properties of complex biological systems

    Science.gov (United States)

    Cartagena-Rivera, Alexander X.

    material properties of living cells and viruses in their respective physiological conditions. This advance is based on the harnessing of sub and superharmonic channels of cantilever vibration which are especially strong in liquids environments, which enable the mapping with exquisite detail of nanoscale material properties. Material properties such as storage and loss modulus or the spring and damping constant in live cells and the repulsive electrostatic force gradient, hydration layer viscosity and adhesion on viruses. By the use of this multi-harmonic dynamic AFM technique using a commercial AFM system, the local material properties of live rat fibroblast cells (RFB), red blood cells (RBC), human breast carcinoma cells (MDA-MB-231), and bacteriophage φ29 mature virions have been successfully imaged and extracted in relevant physiological conditions. Also, a novel high-speed dynamic AFM technique is developed to image at higher spatiotemporal resolution whole live cells under physiological conditions. This high-throughput technology enables the study of cellular processes in near real time frames, for example, the cytoskeleton structure dynamics of live fibroblast cells and human breast carcinoma cells. Overall, the contributions described in this thesis demonstrate the robustness and versatility of these novel advanced dynamic AFM techniques to investigate a wide range of complex biological relevant problems.

  8. 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...

  9. 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)

  10. 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.

  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. Magnesium intake is not related to depression risk in Spanish university graduates.

    Science.gov (United States)

    Derom, Marie-Laure; Martínez-González, Miguel A; Sayón-Orea, Maria del Carmen; Bes-Rastrollo, Maira; Beunza, Juan J; Sánchez-Villegas, Almudena

    2012-06-01

    Magnesium is the second most predominant intracellular cation and it is an important cofactor in over 300 enzymatic reactions. It is a calcium antagonist and a voltage-dependent blocker of the N-methyl-D-aspartate channel, which plays a role in the entrance of calcium into the neuron. Other mechanisms also add biological plausibility to neuro-protective properties for magnesium, including an inverse association with major depression. A higher magnesium intake has been related to lower depressive symptoms. However, epidemiological evidence on this issue is scarce. Our aim was to prospectively evaluate the association between dietary magnesium intake and depression incidence in a cohort of 12,939 Spanish university graduates initially free of depression (Seguimiento Universidad de Navarra Cohort Study). Total magnesium intake was assessed with a validated, semiquantitative FFQ and incident depression was ascertained through self-reports of a new clinical diagnosis of depression done by a medical doctor and/or the habitual use of antidepressive drugs. The self-report was validated against the Diagnostic and Statistical Manual of Mental Disorders (4th edition) criteria in a subsample of the cohort. Cox regression models were used to obtain HR of incident depression during follow-up according to baseline quintiles of magnesium intake using the lowest quintile as the reference category. After a median follow-up of 6.3 y, 737 new cases of depression were identified. No association between magnesium intake and depression was found, with multivariate-adjusted HR = 1 (reference), 1.00 (95% CI: 0.78-1.27), 1.00 (0.76-1.31), 0.95 (0.70-1.30), and 1.11 (0.77-1.59) for increasing categories (quintiles 1-5) of total magnesium intake. No dose-response relationship was found (P-trend = 0.59). Results were robust through different sensitivity analyses, including nutrient density or residual models. In conclusion, our findings do not suggest an inverse association between magnesium

  13. Proficient magnesium nanoferrites: synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Anis-ur-Rehman, M; Malik, Muhammad Ali; Akram, M [Applied Thermal Physics Laboratory, Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan); Khan, Kishwar; Maqsood, Asghari, E-mail: marehman@cosmsats.edu.pk [Thermal Transport Laboratory, School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology, Islamabad (Pakistan)

    2011-01-15

    Ferrite materials are potential candidates for modern technological applications because of their tunable electrical and magnetic properties. The excellent combination of magnetic and dielectric properties of magnesium ferrites can be used to fulfill the future demand for high-frequency applications such as antennas. The electrical transport properties of these materials depend on the synthesis conditions such as sintering and composition. The aim of this work has been to correlate the synthesis conditions and induced electrical transport properties, so that these materials prepared in optimized conditions can be used for the miniaturization of high-frequency application devices. X-ray diffraction (XRD) patterns of samples prepared by the co-precipitation method confirmed the formation of a single spinel phase. The crystallite size, lattice parameters and porosity of the samples were calculated from XRD data. The scanning electron microscopy results showed the formation of rods in the case of the samples sintered at 950 {sup 0}C. All the electrical and dielectric properties showed strong dependence on structural properties. The dielectric constant, dielectric loss tangent and ac electrical conductivity of nanocrystalline Mg ferrites were investigated as a function of frequency and sintering temperature. Dielectric, ac electrical properties and the effect of sintering temperature are explained in accordance with the Maxwell-Wagner and the Koops models.

  14. Fatigue Properties of Cast Magnesium Wheels

    Science.gov (United States)

    Li, Zhenming; Luo, Alan A.; Wang, Qigui; Peng, Liming; Zhang, Peng

    2016-08-01

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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...

  1. 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…

  2. 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)

  3. Investigation of single nucleotide polymorphisms and biological pathways associated with response to TNFα inhibitors in patients with rheumatoid arthritis

    DEFF Research Database (Denmark)

    Krintel, Sophine B; Palermo, Giuseppe; Johansen, Julia S;

    2012-01-01

    Recently, two genome-wide association studies identified single nucleotide polymorphisms (SNPs) significantly associated with the treatment response to tumor necrosis factor α (TNFα) inhibitors in patients with rheumatoid arthritis (RA). We aimed to replicate these results and identify SNPs...... and the possible biological pathways associated with the treatment response to TNFα inhibitors....

  4. 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.…

  5. Association of Magnesium Intake with High Blood Pressure in Korean Adults: Korea National Health and Nutrition Examination Survey 2007-2009.

    Directory of Open Access Journals (Sweden)

    Mi-Kyeong Choi

    Full Text Available 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.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/1000 kcal together with its 95% confidence interval (CI, multivariable logistic regression analysis was performed.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.The present results indicate that sufficient magnesium intake could be useful in decreasing the high blood pressure risk of obese women.

  6. 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

  7. Serum electrolyte and blood gas changes after intrathecal and intravenous bolus injections of magnesium sulphate. An experimental study in a rat model.

    Science.gov (United States)

    Bahar, M; Cohen, M L; Grinshpun, Y; Datski, R; Kaufman, J; Zaidman, J L; Nissenbaum, H; Chanimov, M

    1997-11-01

    The effect of intrathecally administered magnesium sulphate on serum levels of magnesium, sodium, potassium, calcium and blood gas variables was studied in a rat model. Magnesium sulphate given intrathecally has previously been shown to produce segmental spinal blockade with no permanent neurological damage. The previous studies, however, had not investigated the possible systemic effects of the magnesium sulphate. The serum magnesium level increased significantly at 1 and 2 h after the intrathecal injection of both 6.3% and 12.6% magnesium sulphate (6.3%: 28% at 1 h, 24% at 2 h; 12.6%: 22% at 1 h, 16% at 2 h). These changes were not as great as occurred when the same dose of magnesium sulphate was administered intravenously. In all cases, the serum magnesium had returned to normal by 24 h. There were no significant changes in calcium, sodium or potassium levels, nor in arterial blood gas variables. These results show that intrathecally administered magnesium sulphate has little effect on electrolyte homeostasis.

  8. 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.

  9. 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.

  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. Serum magnesium concentration in children with functional constipation treated with magnesium oxide

    Institute of Scientific and Technical Information of China (English)

    Maiko Tatsuki; Reiko Miyazawa; Takeshi Tomomasa; Takashi Ishige; Tomoko Nakazawa; Hirokazu Arakawa

    2011-01-01

    AIM: To determine whether hypermagnesemia recently reported in adult patients possibly develops in children with functional constipation taking daily magnesium oxide.METHODS: We enrolled 120 patients (57 male and 63 female) aged 1-14 years old (median: 4.7 years)with functional constipation from 13 hospitals and two private clinics. All patients fulfilled the Rome Ⅲ criteria for functional constipation and were treated with daily oral magnesium oxide for at least 1 mo. The median treatment dose was 600 (500-800) mg/d. Patients were assessed by an interview and laboratory examination to determine possible hypermagnesemia. Serum magnesium concentration was also measured in sex- and agematched control subjects (n = 38).RESULTS: In the constipation group, serum magnesium concentration [2.4 (2.3-2.5) mg/dL, median and interquartile range] was significantly greater than that of the control group [2.2 (2.0-2.2) mg/dL] (P < 0.001).The highest value was 3.2 mg/dL. Renal magnesium clearance was significantly increased in the constipation group. Serum magnesium concentration in the constipation group decreased significantly with age (P < 0.01).There was no significant correlation between the serum level of magnesium and the duration of treatment with magnesium oxide or the daily dose. None of the patients had side effects associated with hypermagnesemia.CONCLUSION: Serum magnesium concentration increased significantly, but not critically, after daily treatment with magnesium oxide in constipated children with normal renal function.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. The Potential of Magnesium Alloys as Bioabsorbable/ Biodegradable Implants for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    F. Živić

    2014-03-01

    Full Text Available The potential of magnesium alloys as bioabsorbable / biodegradable implants for biomedical applications has been extensively studied as emerging direction. This paper gives a review of current topics in this field. Research activities related to biomedical magnesium alloys have been pursued in two main directions, orthopedic and cardiovascular implants, by investigating different aspects of alloying system design, novel structures, degradation rate control, and surface modification methods. Magnesium alloys are currently considered for applications as load-bearing implant devices such as plates, screws and pins for repairing bone fracture. Highly important direction of research is degradable coronary stents. Degradable vessel stents promote stable vessel regeneration, unlike permanent stents. Different combinations of alloying elements have been investigated in order to decrease corrosion rate.Tribological issues are also important for understanding of different phenomenon related to prolongation of Mg alloys corrosion degradation time/rate, such as tribocorrosion, corrosion fatigue, and fatigue crack growth behavior.

  17. The chemical composition of red giants in 47 Tucanae. II. Magnesium isotopes and pollution scenarios

    CERN Document Server

    Thygesen, A O; Ludwig, H -G; Ventura, P; Yong, D; Collet, R; Christlieb, N; Melendez, J; Zaggia, S

    2016-01-01

    The phenomenon of multiple populations in globular clusters is still far from understood, with several proposed mechanisms to explain the observed behaviour. The study of elemental and isotopic abundance patterns are crucial for investigating the differences among candidate pollution mechanisms. We derive magnesium isotopic ratios for 13 stars in the globular cluster 47 Tucanae (NGC 104) to provide new, detailed information about the nucleosynthesis that has occurred within the cluster. For the first time, the impact of 3D model stellar atmospheres on the derived Mg isotopic ratios is investigated. Using both tailored 1D atmospheric models and 3D hydrodynamical models, we derive magnesium isotopic ratios from four features of MgH near 5135{\\AA} in 13 giants near the tip of the RGB, using high signal-to-noise, high-resolution spectra. We derive the magnesium isotopic ratios for all stars and find no significant offset of the isotopic distribution between the pristine and the polluted populations. Furthermore, ...

  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. Magnesium sulphate and amiodarone prophylaxis for prevention of postoperative arrhythmia in coronary by-pass operations

    Directory of Open Access Journals (Sweden)

    Huysal Kagan

    2009-02-01

    Full Text Available Abstract Background The aim of this study was to investigate the use of prophylactic magnesium sulphate and amiodarone in treating arrhythmias that may occur following coronary bypass grafting operations. Methods The study population consisted of 192 consecutive patients who were undergoing coronary artery bypass grafting (CABG. Sixty-four patients were given 3 g of magnesium sulphate (MgSO4 [20 ml = 24.32 mEq/L Mg+2] in 100 cc of isotonic 0.9% solution over 2 hours intravenously at the following times: 12 hours prior to the operation, immediately following the operation, and on postoperative days 1, 2, and 3 (Group 1. Another group of 64 patients was given a preoperative infusion of amiodarone (1200 mg on first post-operative day (Group 2. After the operation amiodarone was administered orally at a dose of 600 mg/day. Sixty-four patients in group 3 (control group had 100 cc. isotonic 0.9% as placebo, during the same time periods. Results In the postoperative period, the magnesium values were significantly higher in Group 1 than in Group 2 for all measurements. The use of amiodarone for total arrhythmia was significantly more effective than prophylactic treatment with magnesium sulphate (p = 0.015. There was no difference between the two drugs in preventing supraventricular arrhythmia, although amiodarone significantly delayed the revealing time of atrial fibrillation (p = 0.026. Ventricular arrhythmia, in the form of ventricular extra systole, was more common in the magnesium prophylaxis group. The two groups showed no significant differences in other operative or postoperative measurements. No side effects of the drugs were observed. Conclusion Prophylactic use of magnesium sulphate and amiodarone are both effective at preventing arrhythmia that may occur following coronary by-pass operations. Magnesium sulphate should be used in prophylactic treatment since it may decrease arrhythmia at low doses. If arrhythmia should occur despite this

  20. Wood ash as a magnesium source for phosphorus recovery from source-separated urine.

    Science.gov (United States)

    Sakthivel, S Ramesh; Tilley, Elizabeth; Udert, Kai M

    2012-03-01

    Struvite precipitation is a simple technology for phosphorus recovery from source-separated urine. However, production costs can be high if expensive magnesium salts are used as precipitants. Therefore, waste products can be interesting alternatives to industrially-produced magnesium salts. We investigated the technical and financial feasibility of wood ash as a magnesium source in India. In batch experiments with source-separated urine, we could precipitate 99% of the phosphate with a magnesium dosage of 2.7 mol Mg mol P(-1). The availability of the magnesium from the wood ash used in our experiment was only about 50% but this could be increased by burning the wood at temperatures well above 600 °C. Depending on the wood ash used, the precipitate can contain high concentrations of heavy metals. This could be problematic if the precipitate were used as fertilizer depending on the applicable fertilizer regulations. The financial study revealed that wood ash is considerably cheaper than industrially-produced magnesium sources and even cheaper than bittern. However, the solid precipitated with wood ash is not pure struvite. Due to the high calcite and the low phosphorus content (3%), the precipitate would be better used as a phosphorus-enhanced conditioner for acidic soils. The estimated fertilizer value of the precipitate was actually slightly lower than wood ash, because 60% of the potassium dissolved into solution during precipitation and was not present in the final product. From a financial point of view and due to the high heavy metal content, wood ash is not a very suitable precipitant for struvite production. Phosphate precipitation from urine with wood ash can be useful if (1) a strong need for a soil conditioner that also contains phosphate exists, (2) potassium is abundant in the soil and (3) no other cheap precipitant, such as bittern or magnesium oxide, is available. PMID:22297249

  1. The efficacy of magnesium sulfate loading on microalbuminuria following SIRS: One step forward in dosing

    Directory of Open Access Journals (Sweden)

    Mirrahimi Bahador

    2012-10-01

    Full Text Available Abstract Backgrounds Magnesium has been known for its antioxidative and antiinflammatory properties in many studies. In this study two dosing regimens of magnesium were compared with a placebo control group in order to investigate safety and efficacy of high doses of intravenous magnesium sulfate infusion on critically ill trauma patients. Inflammatory and oxidative factors were measured in this trial. Methods 45 trauma patients with systemic inflammatory response syndromes (SIRS were randomly assigned into 2 treatment and one placebo groups. The high dose group received 15 g MgSO4, low dose group received 7.5 g of MgSO4 over 4 hour infusion, and placebo group received saline alone. The initial and post magnesium sulfate injections levels of tumor necrosis factor alpha (TNF-α, total antioxidant power and lipid peroxidation were measured after 6, 18 and 36 hours. The pre-infusion along with 6 and 36 hour level of microalbuminuria were also determined. Results Repeated measurements illustrated that there was no significant difference in TNF-α, total antioxidant power and lipid peroxidation levels among groups during the period of analysis. The microalbuminuria at 36 hour post infusion of high dose group was lower than that of control group (p = 0.024. Patient’s mortality (28 day was similar among all treatment groups. Both magnesium infusion groups tolerated the drug without experiencing any complications. Conclusion No evidence for antioxidative and antiinflammatory effects of magnesium in traumatic SIRS positive patients was found. Magnesium in high doses may be recommended for traumatic patients with SIRS status to prevent microalbuminuria.

  2. The Efficacy of Magnesium Sulfate Loading on Microalbuminuria Following SIRS:One Step forward in Dosing

    Directory of Open Access Journals (Sweden)

    Atabak Najafi

    2012-10-01

    Full Text Available Backgrounds:Magnesium has been known for its antioxidative and antiinflammatory properties in many studies. In this study two dosing regimens of magnesium were compared with a placebocontrol group in order to investigate safety and efficacy of high doses of intravenous magnesium sulfate infusion on critically ill trauma patients. Inflammatory and oxidative factors were measured in this trial.Methods:45 trauma patients with systemic inflammatory response syndromes (SIRS were randomly assigned into 2 treatment and one placebo groups. The high dose group received 15 g MgSO4, low dose group received 7.5 g of MgSO4 over 4 hour infusion, and placebo groupreceived saline alone. The initial and post magnesium sulfate injections levels of tumor necrosis factor alpha (TNF-α, total antioxidant power and lipid peroxidation were measured after 6, 18 and 36 hours. The pre-infusion along with 6 and 36 hour level ofmicroalbuminuria were also determined.Results:Repeated measurements illustrated that there was no significant difference in TNF-α, total antioxidant power and lipid peroxidation levels among groups during the period of analysis.The microalbuminuria at 36 hour post infusion of high dose group was lower than that of control group (p = 0.024. Patient’s mortality (28 day was similar among all treatment groups. Both magnesium infusion groups tolerated the drug without experiencing anycomplications.Conclusion:No evidence for antioxidative and antiinflammatory effects of magnesium in traumatic SIRS positive patients was found. Magnesium in high doses may be recommended for traumaticpatients with SIRS status to prevent microalbuminuria.

  3. Rayleigh surface acoustic wave as an efficient heating system for biological reactions: investigation of microdroplet temperature uniformity.

    Science.gov (United States)

    Roux-Marchand, Thibaut; Beyssen, Denis; Sarry, Frederic; Elmazria, Omar

    2015-04-01

    When a microdroplet is put on the Rayleigh surface acoustic wave path, longitudinal waves are radiated into the liquid and induce several phenomena such as the wellknown surface acoustic wave streaming. At the same time, the temperature of the microdroplet increases as it has been shown. In this paper, we study the temperature uniformity of a microdroplet heated by Rayleigh surface acoustic wave for discrete microfluidic applications such as biological reactions. To precisely ascertain the temperature uniformity and not interfere with the biological reaction, we used an infrared camera. We then tested the temperature uniformity as a function of three parameters: the microdroplet volume, the Rayleigh surface acoustic wave frequency, and the continuous applied radio frequency power. Based on these results, we propose a new device structure to develop a future lab on a chip based on reaction temperatures.

  4. 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 ...

  5. 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

  6. Fixed-wing MAV attitude stability in atmospheric turbulence-Part 2: Investigating biologically-inspired sensors

    Science.gov (United States)

    Mohamed, A.; Watkins, S.; Clothier, R.; Abdulrahim, M.; Massey, K.; Sabatini, R.

    2014-11-01

    Challenges associated with flight control of agile fixed-wing Micro Air Vehicles (MAVs) operating in complex environments is significantly different to any larger scale vehicle. The micro-scale of MAVs can make them particularly sensitive to atmospheric disturbances thus limiting their operation. As described in Part 1, current conventional reactive attitude sensing systems lack the necessary response times for attitude control in high turbulence environments. This paper reviews in greater detail novel and emerging biologically inspired sensors, which can sense the disturbances before a perturbation is induced. A number of biological mechanoreceptors used by flying animals are explored for their utility in MAVs. Man-made attempts of replicating mechanoreceptors have thus been reviewed. Bio-inspired flow and pressure-based sensors were found to be the most promising for complementing or replacing current inertial-based reactive attitude sensors. Achieving practical implementations that meet the size, weight and power constraints of MAVs remains a significant challenge. Biological systems were found to rely on multiple sensors, potentially implying a number of research opportunities in the exploration of heterogeneous bio-inspired sensing solutions.

  7. Effect of an antacid containing magnesium and aluminum on absorption, metabolism, and mechanism of renal elimination of pefloxacin in humans.

    OpenAIRE

    Jaehde, U; Sörgel, F.; Stephan, U.; W. SCHUNACK

    1994-01-01

    The effects of an antacid containing magnesium and aluminum hydroxide on the pharmacokinetics of pefloxacin in 10 healthy volunteers were investigated. In a randomized crossover design, each subject received an oral dose of 400 mg of pefloxacin either with or without multiple doses of the antacid. The concentrations of pefloxacin and its metabolites in plasma and urine were determined by high-performance liquid chromatography assays. We found that coadministration of magnesium and aluminum hy...

  8. Influence of the grain size on the in vivo degradation behaviour of the magnesium alloy LAE442

    OpenAIRE

    Ullmann, Berit; Reifenrath, Janin; Seitz, Jan-Marten; Bormann, Dirk; Meyer-Lindenberg, Andrea

    2013-01-01

    The aim of this study was to investigate the differences in the in vivo degradation behaviour of magnesium implants with various grain sizes and damaged surfaces. For this purpose, three different LAE442 magnesium implants were produced: cast, single and double extruded implants, in order to obtain different grain sizes. Furthermore, defects were positioned on the surfaces of some of the single extruded implants. The initial stability was determined. Four pins of each implant material were im...

  9. Effect of Oral Administration of Magnesium on Cisplatin-Induced Nephrotoxicity in Normal and Streptozocin-Induced Diabetic Rats

    OpenAIRE

    Soltani, Nepton; Nematbakhsh, Mehdi; Eshraghi-Jazi, Fatemeh; Talebi, Ardeshir; Ashrafi, Farzaneh

    2013-01-01

    Background Cisplatin (CP) therapy as the most common potent chemotherapeutic process is accompanied by nephrotoxicity. The diabetic state may protect rat kidney against this toxicity, and magnesium (Mg) on the other hand may reduce the glucose level in diabetic animals. Objectives Current study was planned to investigate the effect of oral administration of magnesium supplementation on CP-induced nephrotoxicity in normal and Streptozocin (STZ)-induced diabetic rats. Materials and Methods Male...

  10. Summary of biological and contaminant investigations related to stream water quality and environmental setting in the Upper Colorado River basin, 1938-95

    Science.gov (United States)

    Deacon, Jeffrey R.; Stephens, Verlin C.

    1996-01-01

    As part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program, an inventory of the biological and contaminant investigations for the Upper Colorado River Basin study unit was conducted. To enhance the sampling design for the biological component of the program, previous studies about the ecology of aquatic organisms and contaminants were compiled from computerized literature searches of biological data bases and by contacting other Federal, State, and local agencies. Biological and contaminant investigations that have been conducted throughout the basin since 1938 were categorized according to four general categories of biological investigations and two categories of contaminant investigations: algal communities, macroinvertebrate communities, fish communities, habitat characterization, contaminants in organism tissue, and contaminants in bed sediment. The studies were identified by their locations in two physiographic provinces, the Southern Rocky Mountains and the Colorado Plateau, and by the predominant land use in the area of the investigation. Studies on algal communities and contaminants in organism tissue and in bed sediment are limited throughout the basin. Studies on macroinvertebrate and fish communities and habitat characterization are the most abundant in the study unit. Natural and human factors can affect biological communities and their composition. Natural factors that affect background water-quality conditions are physiography, climate, geology, and soils. Algae, macroinvertebrates, and fish that are present in the Southern Rocky Mountains and the Colorado Plateau physiographic provinces vary with altitude and physical environment. Green algae and diatoms are predominant in the higher altitude streams, and blue-green, golden-brown, and green algae are predominant in the lower altitude streams. Caddisflies, mayflies, and stoneflies are the dominant macroinvertebrates in the higher altitudes, whereas aquatic worms, leeches

  11. Combustion Synthesis of Magnesium Aluminate

    Science.gov (United States)

    Kale, M. A.; Joshi, C. P.; Moharil, S. V.

    2011-10-01

    In the system MgO-Al2O3, three compounds MgAl2O4, MgAl6O10 (also expressed as- Mg0.4Al2.4O4) and MgAl26O40 are well known. Importance of the first two is well established. Magnesium aluminate (MgAl2O4) spinel is a technologically important material due to its interesting thermal properties. The MgAl2O4 ceramics also find application as humidity sensors. Apart from the luminescence studies, the interest in MgAl2O4 is due to various applications such as humidity-sensing and PEM fuel cells, TL/OSL dosimetry of the ionizing radiations, white light source. Interest in the MgAl6O10 has aroused due to possible use as a substrate for GaN growth. Attempt was made to synthesize these compounds by the combustion synthesis using metal nitrates as oxidizer and urea as a fuel. Compounds MgAl2O4 and MgAl6O10 were formed in a single step, while MgAl26O40 was not formed by this procedure. Activation of MgAl6O10 by rare earth ions like Ce3+, Eu3+ and Tb3+ and ns2 ion Pb2+ could be achieved. Excitation bands for MgAl6O10 are at slightly shorter wavelengths compared to those reported for MgAl2O4.

  12. Copper-Silicon-Magnesium Alloys for Latent Heat Storage

    Science.gov (United States)

    Gibbs, P. J.; Withey, E. A.; Coker, E. N.; Kruizenga, A. M.; Andraka, C. E.

    2016-06-01

    The systematic development of microstructure, solidification characteristics, and heat of solidification with composition in copper-silicon-magnesium alloys for thermal energy storage is presented. Differential scanning calorimetry was used to relate the thermal characteristics to microstructural development in the investigated alloys and clarifies the location of one of the terminal three-phase eutectics. Repeated thermal cycling highlights the thermal storage stability of the transformation through multiple melting events. Two near-terminal eutectic alloys display high enthalpies of solidification, relatively narrow melting ranges, and stable transformation hysteresis behaviors suited to thermal energy storage.

  13. The Humidity Sensor Using the Polyacrylic Emulsion Containing Magnesium Chloride

    Institute of Scientific and Technical Information of China (English)

    Ching-Han Yu; Jung-Chuan Chou; Tai-Ping Sun; Shen-Kan Hsiung

    2006-01-01

    An impedance type humidity sensor based on the polyacrylic emulsion containing magnesium chloride (MgCl2)without chemical modification was investigated. The impedances of the sensor were measured from various relative humidity in the frequency range between 0.1kHz and 100 kHz. The sensor has a good sensitivity from 60%RH to 90%RH. According to the experimental results, the response time is about 240 seconds in the adsorption process and 310 seconds in the desorption process.

  14. Corrosion behaviour of aluminium-magnesium alloys in molten sodium

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The corrosion behaviour of the Al-1% Mg, A1-3% Mg, A1-5% Mg and A1-3% Mg-0.15%Zr alloys in moltensodium was investigated. The morphology of the corrosion products and the alloying element distribution of the specimenswere analyzed by using OM, SEM and EDS. The results showed that the effects of the magnesium content and the im-mersion temperature on the corrosion of the specimens are related to β phase (Mg5Al8).

  15. An investigation of the pathophysiological mechanisms of hydrofluoric acid intoxication in rats and pigs. Interim report concerning the results of phase 2.1: The effect of sodium fluoride infusion on the plasma concentrations of lactate and magnesium

    NARCIS (Netherlands)

    Boink ABTJ; de Wildt DJ; de Jong Y; de Groot G; Vaessen HAMG; Meulenbelt J; van Dijk A; Vosmeer H

    1990-01-01

    From a previous study it was concluded that intravenous infusion of sodium fluoride (NaF) in rats is a suitable model to study the toxicity of hydrofluoric acid. In this supplementary study we investigated the effect of intravenous infusion of a high and low dose of NaF (120 and 25 mg.kg -1.hr -1

  16. Small for Gestational Age and Magnesium: Intrauterine magnesium deficiency may induce metabolic syndrome in later life

    Directory of Open Access Journals (Sweden)

    Junji Takaya

    2015-12-01

    Full Text Available Magnesium deficiency during pregnancy as a result of insufficient or low intake of magnesium is common in developing and developed countries. Previous reports have shown that intracellular magnesium of cord blood platelets is lower among small for gestational age (SGA groups than that of appropriate for gestational age (AGA groups, suggesting that intrauterine magnesium deficiency may result in SGA. Additionally, the risk of adult-onset diseases such as insulin resistance syndrome is greater among children whose mothers were malnourished during pregnancy, and who consequently had a low birth weight. In a number of animal models, poor nutrition during pregnancy leads to offspring that exhibit pathophysiological changes similar to human diseases. The offspring of pregnant rats fed a magensium restricted diet have developed hypermethylation in the hepatic 11β-hydroxysteroid dehydrogenase-2 promoter. These findings indicate that maternal magnesium deficiencies during pregnancy influence regulation of non-imprinted genes by altering the epigenetic regulation of gene expression, thereby inducing different metabolic phenotypes. Magnesium deficiency during pregnancy may be responsible for not only maternal and fetal nutritional problems, but also lifelong consequences that affect the offspring throughout their life. Epidemiological, clinical, and basic research on the effects of magnesium deficiency now indicates underlying mechanisms, especially epigenetic processes.

  17. Investigation of the Relation Between Intelligence Areas According to Multiple Intelligence Theory and Academic Success in Biology Lesson and Sex of ninth Grade Students.

    OpenAIRE

    Kurt, Murat; Ayhan ÇİNİCİ; DEMİR, Yavuz

    2011-01-01

    The aim of this study is to identify the relationship between grade 9 Students’ intelligence domains in the Multiple Intelligence Theory (MIT) and biology achievement and determine the relationship between the intelligence domains and gender. Investigation is a definitive field research in which scanning model was used. Study universe was accepted also as sample and 80 students from three different ninth grade classes (9/A, 9/C, and 9/E) form...

  18. Solid-state rechargeable magnesium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Chusid, O.; Gofer, Y.; Gizbar, H.; Vestfrid, Y.; Levi, E.; Aurbach, D. [Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900 (Israel); Riech, I. [Ortal Magnesium Diecasting Ltd, Kibbutz Neve Ur 10875 (Israel)

    2003-04-17

    The development of all solid-state rechargeable magnesium battery systems is reported, with components that are environmentally friendly and relatively simple in their structure and preparation. As anodes, magnesium alloys containing Zn and Al are used, and the cathode is the chevrel phase, Mo{sub 6}S{sub 8}, which can insert two magnesium atoms per unit (Mg{sub 2}Mo{sub 6}S{sub 8}, 122 mA h g{sup -1}). The solid electrolyte is a gel comprising polyvinylidene difluoride, Mg(AlCl{sub 2}EtBt){sub 2} complex salt, and tetraglyme as a plasticizer. These batteries are found to function well in a temperature range of 0-80 C with a voltage range of 1.3-0.8V. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  19. Magnesium sulfate administration in subarachnoid hemorrhage.

    Science.gov (United States)

    Suarez, Jose I

    2011-09-01

    Magnesium offers theoretic vascular and neuroprotective benefits for patients with subarachnoid hemorrhage. An electronic literature search was conducted to identify original research studies describing intravenous magnesium treatment in patients with SAH published in English between January 1990 and October 2010. Seventeen articles were identified and reviewed, including one phase III randomized-controlled clinical trial and six phase II randomized-controlled trials. Study quality was low for most of the included studies, with the phase III trial considered to be of moderate quality. Due to inconsistently reported benefits and the occurrence of side effects, phase II data suggested that intravenous magnesium for SAH provided either no overall net benefit or uncertain trade-offs. Benefit was likewise not supported in the single phase III clinical trial. PMID:21748496

  20. Association of helicobacter pylori infection with serum magnesium in kidney transplant patients

    Science.gov (United States)

    Hafizi, Massoud; Mardani, Saeed; Borhani, Ali; Ahmadi, Ali; Nasri, Parto; Nasri, Hamid

    2014-01-01

    Introduction: Few studies are available regarding the various promoting factors of H. pylori infection in kidney disease patients especially renal transplant individuals. Objectives: This study was therefore conducted to examine the association of serum magnesium with H. pylori infection among kidney transplant patients. This cross-sectional investigation was conducted on a group of stable kidney transplant patients. Peripheral venous blood samples were collected for biochemical analysis after an overnight fast, Also urea breath test (UBT) was conducted for patients. Patients and Methods: A total of 50 cases was enrolled to the study. Mean serum magnesium value of the patients was 1.98 ± 0.62 mg/dl. Serum magnesium level in positive H. pylori patients was more than negative H. pylori patients (p=0.0005). In this study population, there was no significant difference in serum intact PTH, calcium, alkaline phosphatase, albumin levels and body mass index (BMI) between males and females or H. pylori positive and H. pylori negative subjects (p>0.5). Conclusion: It is possible that, magnesium aggravates H. pylori infection in kidney transplant patients through the mechanisms like hemodialysis, which we had reported previously. However, more studies are necessary to prove the association of magnesium with H. pylori infection in renal transplant patients and finding the clinical relevance of our findings. PMID:25610889

  1. Preparation of magnesium hydroxide nanoflowers from boron mud via anti-drop precipitation method

    International Nuclear Information System (INIS)

    Highlights: • We use the anti-drop precipitation method for synthesis of magnesium hydroxide. • Boron mud which is solid waste from a borax factory is used as the magnesium source. • The magnesium hydroxide nanoflowers are prepared in a short time. • The as-prepared magnesium hydroxide can be used as an effective flame retardant. - Abstract: Using boron mud as the starting material, the flower-like magnesium hydroxide (MH) has been successfully prepared via anti-drop precipitation method. The effect of NH3·H2O concentration, aging time, and surfactant on the morphology of MH was investigated. The optimum precipitation conditions are dropping MgSO4 solution in 5% NH3·H2O solution, with 3% polyethylene glycol as surfactant, aging for 30 min. XRD, SEM, FI-IR, and TG/DTA have been employed to characterize the as-prepared samples. XRD reveals that MH with high purity has the brucite structure. SEM images show that the flower-like MH exists in the form of mono-disperse well uniform spherical aggregation with diameter of 3–5 μm. TG/DTA shows a total percentage of weight loss 33.6% with a well-defined endothermic peak near 381.3 °C corresponding to the decomposition of MH. Furthermore, it reports that the extremely fast primary nucleation is of significance for crystal growth of MH

  2. Preparation of magnesium hydroxide nanoflowers from boron mud via anti-drop precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xi [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Blue Sky Technology Corporation, Beijing 100083 (China); Ma, Hongwen, E-mail: mahw@cugb.edu.cn [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Jiang, Xiaoqian [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Jiang, Zhouqing [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Blue Sky Technology Corporation, Beijing 100083 (China)

    2014-08-15

    Highlights: • We use the anti-drop precipitation method for synthesis of magnesium hydroxide. • Boron mud which is solid waste from a borax factory is used as the magnesium source. • The magnesium hydroxide nanoflowers are prepared in a short time. • The as-prepared magnesium hydroxide can be used as an effective flame retardant. - Abstract: Using boron mud as the starting material, the flower-like magnesium hydroxide (MH) has been successfully prepared via anti-drop precipitation method. The effect of NH{sub 3}·H{sub 2}O concentration, aging time, and surfactant on the morphology of MH was investigated. The optimum precipitation conditions are dropping MgSO{sub 4} solution in 5% NH{sub 3}·H{sub 2}O solution, with 3% polyethylene glycol as surfactant, aging for 30 min. XRD, SEM, FI-IR, and TG/DTA have been employed to characterize the as-prepared samples. XRD reveals that MH with high purity has the brucite structure. SEM images show that the flower-like MH exists in the form of mono-disperse well uniform spherical aggregation with diameter of 3–5 μm. TG/DTA shows a total percentage of weight loss 33.6% with a well-defined endothermic peak near 381.3 °C corresponding to the decomposition of MH. Furthermore, it reports that the extremely fast primary nucleation is of significance for crystal growth of MH.

  3. Influence of recycled fine aggregates on the resistance of mortars to magnesium sulfate attack.

    Science.gov (United States)

    Lee, Seung-Tae

    2009-08-01

    The influence of recycled fine aggregates, which had been reclaimed from field-demolished concretes, on the resistance of mortar specimens to magnesium sulfate attack was investigated. Mortar specimens were prepared with recycled fine aggregates at different replacement levels (0%, 25%, 50%, 75% and 100% of natural fine aggregate by mass). The mortar specimens were exposed to 4.24% magnesium sulfate solution for about 1 year at ambient temperature, and regularly monitored for visual appearance, compressive strength loss and expansion. Additionally, in order to identify products of magnesium sulfate attack, mortar samples incorporating 0%, 25% and 100% replacement levels of the recycled fine aggregates were examined by X-ray diffraction (XRD) technique. Experimental results confirmed that the use of recycled fine aggregates up to a maximum 50% replacement level is effective under severe magnesium sulfate environment, irrespective of type of recycled fine aggregates. However, the worse performance was observed in mortar specimens incorporating 100% replacement level. It was found that the water absorption of recycled fine aggregates affected deterioration of mortar specimens, especially at a higher replacement level. XRD results indicated that the main cause of deterioration of the mortar specimens was primarily due to the formation of gypsum and thaumasite by magnesium sulfate attack. In addition, it appeared that the conversion of C-S-H into M-S-H by the attack probably influenced mechanical deterioration of mortar specimens with recycled fine aggregates. PMID:19467853

  4. Influence of recycled fine aggregates on the resistance of mortars to magnesium sulfate attack.

    Science.gov (United States)

    Lee, Seung-Tae

    2009-08-01

    The influence of recycled fine aggregates, which had been reclaimed from field-demolished concretes, on the resistance of mortar specimens to magnesium sulfate attack was investigated. Mortar specimens were prepared with recycled fine aggregates at different replacement levels (0%, 25%, 50%, 75% and 100% of natural fine aggregate by mass). The mortar specimens were exposed to 4.24% magnesium sulfate solution for about 1 year at ambient temperature, and regularly monitored for visual appearance, compressive strength loss and expansion. Additionally, in order to identify products of magnesium sulfate attack, mortar samples incorporating 0%, 25% and 100% replacement levels of the recycled fine aggregates were examined by X-ray diffraction (XRD) technique. Experimental results confirmed that the use of recycled fine aggregates up to a maximum 50% replacement level is effective under severe magnesium sulfate environment, irrespective of type of recycled fine aggregates. However, the worse performance was observed in mortar specimens incorporating 100% replacement level. It was found that the water absorption of recycled fine aggregates affected deterioration of mortar specimens, especially at a higher replacement level. XRD results indicated that the main cause of deterioration of the mortar specimens was primarily due to the formation of gypsum and thaumasite by magnesium sulfate attack. In addition, it appeared that the conversion of C-S-H into M-S-H by the attack probably influenced mechanical deterioration of mortar specimens with recycled fine aggregates.

  5. Statistical model for combustion of high-metal magnesium-based hydro-reactive fuel

    Institute of Scientific and Technical Information of China (English)

    Hu Jian-Xin; Han Chao; Xia Zhi-Xun; Huang Li-Ya; Huang Xu

    2012-01-01

    We investigate experimentally and analytically the combustion behavior of a high-metal magnesium-based hydro-reactive fuel under high temperature gaseous atmosphere.The fuel studied in this paper contains 73% magnesium powders.An experimental system is designed and experimeuts are carried out in both argon and water vapor atmospheres.It is found that the burning surface temperature of the fuel is higher in water vapor than that in argon and both of them are higher than the melting point of magnesium,which indicates the molten state of magnesium particles in the burning surface of the fuel.Based on physical considerations and experimental results,a mathematical one-dimensional model is formulated to describe the combustion behavior of the high-metal magnesium-based hydro-reactive fuel.The model enables the evaluation of the burning surface temperature,the burning rate and the flame standoff distance each as a function of chamber pressure and water vapor concentration.The results predicted by the model show that the burning rate and the surface temperature increase when the chamber pressure and the water vapor concentration increase,which are in agreement with the observed experimental trends.

  6. Effect of Mixing on Properties and Microstructure of Magnesium Oxychloride Cement

    Institute of Scientific and Technical Information of China (English)

    HE Zhenhui; YANG Hongjian; SONG Hui; GUO Tao; WU Songyi

    2016-01-01

    This paper investigated the effect of mixing on the properties of magnesium oxychloride cement, such as ap-parent viscosity, setting time, compressive strength, and specific strength as well. The phase composition and crystallo-graphic structure of the cement were determined by X-ray diffraction and scanning electron microscopy. The results in-dicate that the increases of stirring rate and mixing time change apparent viscosity distinctly, shorten setting time and enhance mechanical property. Magnesium oxychloride cement after mixing for 20 min exhibits the optimal mechanical performance. The effect of stirring rate on the phase composition of magnesium oxychloride cement dominates over the effect of mixing time. The increases of stirring rate and mixing time can increase the dispersion state and accelerate the neutralization, thus promoting the strength of magnesium oxychloride cement due to the formation of stable 5·1·8 phase, needle-like crystals and continuous crystalline structure in the whole cement matrix. The properties and microstructure of magnesium oxychloride cement at a stirring rate of 280 rpm are better than those at 140 rpm.

  7. The viability of aluminum Zintl anion moieties within magnesium-aluminum clusters

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haopeng; Jae Ko, Yeon; Zhang, Xinxing; Gantefoer, Gerd; Bowen, Kit H., E-mail: kiran@mcneese.edu, E-mail: akandalam@wcupa.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Schnoeckel, Hansgeorg [Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Eichhorn, Bryan W. [Department of Chemistry, University of Maryland, College Park, Maryland 20742 (United States); Jena, Puru [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Kiran, Boggavarapu, E-mail: kiran@mcneese.edu, E-mail: akandalam@wcupa.edu, E-mail: kbowen@jhu.edu [Department of Chemistry, McNeese State University, Lake Charles, Louisiana 70609 (United States); Kandalam, Anil K., E-mail: kiran@mcneese.edu, E-mail: akandalam@wcupa.edu, E-mail: kbowen@jhu.edu [Department of Physics, West Chester University, West Chester, Pennsylvania 19383 (United States)

    2014-03-28

    Through a synergetic combination of anion photoelectron spectroscopy and density functional theory based calculations, we have investigated the extent to which the aluminum moieties within selected magnesium-aluminum clusters are Zintl anions. Magnesium-aluminum cluster anions were generated in a pulsed arc discharge source. After mass selection, photoelectron spectra of Mg{sub m}Al{sub n}{sup −} (m, n = 1,6; 2,5; 2,12; and 3,11) were measured by a magnetic bottle, electron energy analyzer. Calculations on these four stoichiometries provided geometric structures and full charge analyses for the cluster anions and their neutral cluster counterparts, as well as photodetachment transition energies (stick spectra). Calculations revealed that, unlike the cases of recently reported sodium-aluminum clusters, the formation of aluminum Zintl anion moieties within magnesium-aluminum clusters was limited in most cases by weak charge transfer between the magnesium atoms and their aluminum cluster moieties. Only in cases of high magnesium content, e.g., in Mg{sub 3}Al{sub 11} and Mg{sub 2}Al{sub 12}{sup −}, did the aluminum moieties exhibit Zintl anion-like characteristics.

  8. Magnesium improves hydrogen production by a novel fermentative hydrogen-producing bacterial strain B49

    Institute of Scientific and Technical Information of China (English)

    WANG Xiang-jing; REN Nan-qi; XIANG Wen-sheng

    2005-01-01

    Batch experiments were conducted to investigate the effects of magnesium on glucose metabolism, including growth and hydrogen-producing capacity of fermentative hydrogen-producing bacterial strain B49. These abilities were enhanced with an increase in magnesium concentration. At the end of fermentation from 10 g/L ratio of ethanol amount (mg/L) to acetate amount (mg/L) was 1.1, and the accumulated hydrogen volume hydrogen volume was increased to 2 360. 5 mL H2/L culture, the ratio of ethanol amount (mg/L) to acetate amount (mg/L) was increased to 1.3 and polysaccharide was decreased to 2. 5 mg/L. Moreover, the magnesium solution addition to the medium at different fermentation times affected hydrogen-producing ability. However,the later the addition time was postponed, the less the effect was on hydrogen evolution. Further experiments confirmed the enhancement was dependent on magnesium ions and not on the other inorganic ions such as SO42- or Cl-, which constituted the magnesium salts.

  9. Biological diversity and boreal forest ecosystem stability : an investigation of the predictions of the diversity-stability hypothesis

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, T.; James, P. [Regina Univ., Regina, SK (Canada)

    1999-05-01

    The controversy regarding the role of biological diversity in the stabilization of ecosystems was reviewed. The presentation examined the correctness of the current theory that greater diversity leads to greater ecosystem stability. The relationship was tested by quantifying the resistance and resilience of the boreal forest beetle community assemblages found in two different habitat types (jack pine and mixed-wood). Both habitat types were subjected to large scale disturbances, including fire, clear-cutting, and post-fire harvesting. The study showed that the relative abundances of beetle community assemblages found in jack pines were much more resistant to all disturbances tested than those found in mixed-wood.

  10. Investigations on the relative biologic effectiveness of fast neutrons in barley and maize after dry seed irradiation

    International Nuclear Information System (INIS)

    The spring barley cultivar Elsa and the inbred maize line S-144 were used. Seeds having 12% moisture were irradiated with 4 doses of γ-rays and fast neutrons. The relative biologic effectiveness (RBE) was determined in regard to germination, sterility and chlorophyll mutation frequency. RBE-values for barley varied within the range of 15 to 31 for the individual criteria, while for maize the range was 4 to 14 respectively. It was established that with the rise in fast neutron irradiation doses RBE diminishes. (author)

  11. Small for Gestational Age and Magnesium in Cord Blood Platelets: Intrauterine Magnesium Deficiency May Induce Metabolic Syndrome in Later Life

    Directory of Open Access Journals (Sweden)

    Junji Takaya

    2011-01-01

    Full Text Available Magnesium deficiency in pregnancy frequently occurs because of inadequate or low intake of magnesium. Magnesium deficiency during pregnancy can induce not only maternal and fetal nutritional problems, but also consequences that might last in offspring throughout life. Many epidemiological studies have disclosed that small for gestational age (SGA is associated with an increased risk of insulin resistance in adult life. We reported that intracellular magnesium of cord blood platelets is lower in SGA groups than that in appropriate for gestational age groups, suggesting that intrauterine magnesium deficiency may result in SGA. Taken together, intrauterine magnesium deficiency in the fetus may lead to or at least program insulin resistance after birth. In this review, we propose that intrauterine magnesium deficiency may induce metabolic syndrome in later life. We discuss the potential contribution of aberrant magnesium regulation to SGA and to the pathogenesis of metabolic syndrome.

  12. Magnesium retention in 12 to 48 month-old children

    Science.gov (United States)

    In adults, adaptation to changes in magnesium intake is largely due to changes in fractional magnesium absorption and urinary magnesium excretion. We sought to examine whether these homeostatic mechanisms also occur in young children. Children, 12–48 m old, were studied (n=30). They were adapted to ...

  13. Magnesium Intake and Prevalence of Metabolic Syndrome in Older Adults

    Science.gov (United States)

    Higher dietary intake of magnesium (Mg) may protect against development of type 2 diabetes. The aim of this study was to examine the association between dietary magnesium intake and metabolic syndrome risk factors in elderly men and women. We examined cross-sectional associations between magnesium i...

  14. New development of anodizing process of magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    BAI Li-qun; LI Di

    2004-01-01

    Magnesium alloy, a kind of environment-friendly material with promising and excellent properties, is a good choice for a number of applications. The research and development of anodizing on magnesium alloys and its application situation are reviewed, and the anodizing development trend on magnesium alloys is summarized.

  15. 40 CFR 721.9513 - Modified magnesium silicate polymer (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified magnesium silicate polymer... Specific Chemical Substances § 721.9513 Modified magnesium silicate polymer (generic). (a) Chemical... as modified magnesium silicate polymer (PMN P-98-604) is subject to reporting under this section...

  16. Grain refinement of AZ31 magnesium alloy by electromagnetic stirring under effect of grain-refiner

    Indian Academy of Sciences (India)

    S Y Gao; Q C Le; Z Q Zhang; J Z Cui

    2012-08-01

    The effects of electromagnetic stirring and Al4C3 grain refiner on the grain refinement of semicontinuously cast AZ31 magnesium alloy were discussed in this investigation. The results indicate that electromagnetic stirring has an effective refining effect on the grain size of AZ31 magnesium alloy under the effect of Al4C3 grain refiner. Electromagnetic stirring can `activate’ the Al4C3 particles, resulting in more heterogeneous nucleation sites for the primary -Mg grains. But, longer holding time can `deactivate’ the Al4C3 particles and poison the grain refining effect.

  17. Study on the isothermal forging process of MB26 magnesium alloy adaptor

    Directory of Open Access Journals (Sweden)

    Xu Wenchen

    2015-01-01

    Full Text Available 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 distributed along the contour of the complex-shaped adaptor forging.

  18. Removal of Indigo Carmine Dye from Aqueous Solution Using Magnesium Hydroxide as an Adsorbent

    OpenAIRE

    Thimmasandra Narayan Ramesh; Vani Pavagada Sreenivasa

    2015-01-01

    Magnesium hydroxide is used as an adsorbent for the removal of indigo carmine dye from aqueous solution. We have investigated the effectiveness of removal of indigo carmine dye from aqueous solutions at pH 6-7 and 12-13 using magnesium hydroxide thereby varying the dose of the adsorbent, concentration of the dye, duration, and temperature. Structural transformations of adsorbent during the adsorption process at different pH values are monitored using powder X-ray diffraction and infrared spec...

  19. Review of grain refinement methods for as-cast microstructure of magnesium alloy

    Directory of Open Access Journals (Sweden)

    Song Changjiang

    2009-05-01

    Full Text Available As the lightest structural metal, Mg and Mg-based alloys have great potential applications in the aerospace, automotive and nuclear industries. However, such applications have been limited by low ductility and strength. Theoretically, small grain sized structure can synchronously improve its ductility and strength. Yet, universally reliable grain refi nement techniques for the magnesium alloys are still under investigation and some are in strong debating. This paper presents a brief review of development of grain refi nement methods for magnesium alloys, which would contribute to a better understanding of the factors controlling grain refi nement and provide an outlook of future research in this field.

  20. Application of Severe Plastic Deformation Techniques to Magnesium for Enhanced Hydrogen Sorption Properties

    Directory of Open Access Journals (Sweden)

    Daniel Fruchart

    2012-08-01

    Full Text Available In this paper we review the latest developments in the use of severe plastic deformation (SPD techniques for enhancement of hydrogen sorption properties of magnesium and magnesium alloys. Main focus will be on two techniques: Equal Channel Angular Pressing (ECAP and Cold Rolling (CR. After a brief description of these two techniques we will discuss their effects on the texture and hydrogen sorption properties of magnesium alloys. In particular, the effect of the processing temperature in ECAP on texture will be demonstrated. We also show that ECAP and CR have produced different textures. Despite the scarcity of experimental results, the investigations up to now indicate that SPD techniques produce metal hydrides with enhanced hydrogen storage properties.