Science.gov

Sample records for magnesium 26 reactions

  1. Stretched-state excitations with the (neutron,proton) reaction at 278 MeV on carbon-14, magnesium-26 and silicon-30

    NASA Astrophysics Data System (ADS)

    Hu, Xiao-Dong

    1997-11-01

    The reactions 12C(n,p)12B,/ 14C(n,p)14B,/ 16O(n,p)16N,/ 26Mg(n,p)26Na and 30Si(n,p)30Al were studied at a neutron energy of 278 MeV using the charge-exchange facility at the TRIUMF accelerator laboratory in Vancouver, Canada. Excitation-energy spectra and differential cross sections for the observed excitations in these reactions were extracted over the momentum-transfer range from 1.2 to 2.5 fm-1 (θlab in 19o,/ 23o,/ 27o,/ 31o and 35o). The primary goal of this work was the study of T = 2 'stretched' particle-hole states, more specifically (/nu d5/2,/ /pi p3/2-1)/ 4/sp- states excited in 14B,/ (/nu f7/2,/pi d5/2-1)/ 6/sp- states excited in 26Na, and (/nu f7/2,/ /pi d5/2-1)/ 6/sp- states excited in 30Al. The identification of these states was based on: (1) comparison of the experimental cross section angular distribution with theoretical differential cross sections calculated with the distorted-wave-impulse approximation (DWIA); (2) comparison of the measured excitation energies with excitation energies of analog stretched states; and (3) comparison of the spectroscopic strength for these (n,p) reactions to (p,n) and (e,e') spectroscopic strengths. The T = 1 (/nu d5/2,/ /pi p3/2-1)/ 4/sp- 'stretched' states excited in 12B and 16N were also studied. For the 12C(n,p)12B reaction (on targets of CH2 and graphite), 4/sp- T = 1 strength at Ex = 4.25 MeV was observed and found to be consistent with previous measurements; this state was used for calibrating excitation-energy scales for the other targets and as a consistency check among the different experimental runs for this project.

  2. Magnesium stearine production via direct reaction of palm stearine and magnesium hydroxide

    NASA Astrophysics Data System (ADS)

    Pratiwi, M.; Ylitervo, P.; Pettersson, A.; Prakoso, T.; Soerawidjaja, T. H.

    2017-06-01

    The fossil oil production could not compensate with the increase of its consumption, because of this reason the renewable alternative energy source is needed to meet this requirement of this fuel. One of the methods to produce hydrocarbon is by decarboxylation of fatty acids. Vegetable oil and fats are the greatest source of fatty acids, so these can be used as raw material for biohydrocarbon production. From other researchers on their past researchs, by heating base soap from divalent metal, those metal salts will decarboxylate and produce hydrocarbon. This study investigate the process and characterization of magnesium soaps from palm stearine by Blachford method. The metal soaps are synthesized by direct reaction of palm stearine and magnesium hydroxide to produce magnesium stearine and magnesium stearine base soaps at 140-180°C and 6-10 bar for 3-6 hours. The operation process which succeed to gain metal soaps is 180°C, 10 bar, for 3-6 hours. These metal soaps are then compared with commercial magnesium stearate. Based on Thermogravimetry Analysis (TGA) results, the decomposition temperature of all the metal soaps were 250°C. Scanning Electron Microscope with Energy Dispersive X-ray (SEM-EDX) analysis have shown the traces of sodium sulphate for magnesium stearate commercial and magnesium hydroxide for both type of magnesium stearine soaps. The analysis results from Microwave Plasma-Atomic Emission Spectrometry (MP-AES) have shown that the magnesium content of magnesium stearine approximate with magnesium stearate commercial and lower compare with magnesium stearine base soaps. These experiments suggest that the presented saponification process method could produced metal soaps comparable with the commercial metal soaps.

  3. The magnesium isotope (δ26Mg) signature of dolomites

    NASA Astrophysics Data System (ADS)

    Geske, A.; Goldstein, R. H.; Mavromatis, V.; Richter, D. K.; Buhl, D.; Kluge, T.; John, C. M.; Immenhauser, A.

    2015-01-01

    Dolomite precipitation models and kinetics are debated and complicated due to the complex and temporally fluctuating fluid chemistry and different diagenetic environments. Using well-established isotope systems (δ18O, δ13C, 87Sr/86Sr), fluid inclusions and elemental data, as well as a detailed sedimentological and petrographic data set, we established the precipitation environment and subsequent diagenetic pathways of a series of Proterozoic to Pleistocene syn-depositional marine evaporative (sabkha) dolomites, syn-depositional non-marine evaporative (lacustrine and palustrine) dolomites, altered marine ("mixing zone") dolomites and late diagenetic hydrothermal dolomites. These data form the prerequisite for a systematic investigation of dolomite magnesium isotope ratios (δ26Mgdol). Dolomite δ26Mg ratios documented here range, from -2.49‰ to -0.45‰ (δ26Mgmean = -1.75 ± 1.08‰, n = 42). The isotopically most depleted end member is represented by earliest diagenetic marine evaporative sabkha dolomites (-2.11 ± 0.54‰ 2σ, n = 14). In comparing ancient compositions to modern ones, some of the variation is probably due to alteration. Altered marine (-1.41 ± 0.64‰ 2σ, n = 4), and earliest diagenetic lacustrine and palustrine dolomites (-1.25 ± 0.86‰ 2σ, n = 14) are less negative than sabkha dolomites but not distinct in composition. Various hydrothermal dolomites are characterized by a comparatively wide range of δ26Mg ratios, with values of -1.44 ± 1.33‰ (2σ, n = 10). By using fluid inclusion data and clumped isotope thermometry (Δ47) to represent temperature of precipitation for hydrothermal dolomites, there is no correlation between fluid temperature (∼100 to 180 °C) and dolomite Mg isotope signature (R2 = 0.14); nor is there a correlation between δ26Mgdol and δ18Odol. Magnesium-isotope values of different dolomite types are affected by a complex array of different Mg sources and sinks, dissolution/precipitation and non

  4. Stoichiometry of the Reaction of Magnesium with Hydrochloric Acid

    NASA Astrophysics Data System (ADS)

    Chebolu, Venkat; Storandt, Barbara C.

    2003-03-01

    This experiment determines the stoichiometry of a reaction of magnesium and HCl by measuring the pressure of the hydrogen gas produced using a PASCO Absolute Pressure Sensor and a PASCO Science Workshop 500 computer interface. A constant amount of excess HCl is reacted with varying amounts of magnesium solid. The change in pressure in a constant-volume (500-mL Erlenmeyer flask) system is measured. The relationship between moles of magnesium reacted and moles of hydrogen produced are plotted. The primary advantage of this simple procedure is the opportunity for continuous interaction between the teacher, students, and data as the data are being collected. Additional advantages are that students can run several samples in a relatively short time (at least five in a three-hour period) and can develop a real-time understanding of the relationship between the amount of gas produced by a reaction and the pressure in the reaction container. The experiment incorporates the use of technology, graphing, and spreadsheet data analysis and is appropriate for either a general or introductory chemistry laboratory.

  5. Preparation of functionalized cyclic enol phosphates by halogen-magnesium exchange and directed deprotonation reactions.

    PubMed

    Piller, Fabian M; Bresser, Tomke; Fischer, Markus K R; Knochel, Paul

    2010-07-02

    Cyclic enol phosphates were magnesiated by a halogen/magnesium exchange reaction or deprotonation using TMP-derived magnesium amide bases. The resulting magnesium reagents react readily with a wide range of electrophiles like allyl bromides and acid chlorides or can be used in Pd-catalyzed cross-coupling reactions. Several optically pure enol phosphates were prepared starting from readily available d-(+)-camphor derivatives.

  6. Isotopic mass fractionation laws for magnesium and their effects on 26Al-26Mg systematics in solar system materials

    NASA Astrophysics Data System (ADS)

    Davis, Andrew M.; Richter, Frank M.; Mendybaev, Ruslan A.; Janney, Philip E.; Wadhwa, Meenakshi; McKeegan, Kevin D.

    2015-06-01

    Magnesium isotope ratios are known to vary in solar system objects due to the effects of 26Al decay to 26Mg and mass-dependent fractionation, but anomalies of nucleosynthetic origin must also be considered. In order to infer the amount of enhancement of 26Mg/24Mg due to 26Al decay or to resolve small nucleogenetic anomalies, the exact relationship between 26Mg/24Mg and 25Mg/24Mg ratios due to mass-dependent fractionation, the mass-fractionation "law", must be accurately known so that the 25Mg/24Mg ratio can be used to correct the 26Mg/24Mg ratio for mass fractionation. Mass-dependent fractionation in mass spectrometers is reasonably well characterized, but not necessarily fully understood. It follows a simple power fractionation law, sometimes referred to as the "exponential law". In contrast, mass fractionation in nature, in particular that due to high temperature evaporation that likely caused the relatively large effects observed in calcium-, aluminum-rich inclusions (CAIs), is reasonably well understood, but mass-fractionation laws for magnesium have not been explored in detail. The magnesium isotopic compositions of CAI-like evaporation residues produced in a vacuum furnace indicate that the slope on a log 25Mg/24Mg vs. log 26Mg/24Mg plot is ∼0.5128, and different from those predicted by any of the commonly used mass-fractionation laws. Evaporation experiments on forsterite-rich bulk compositions give exactly the same slope, indicating that the measured mass-fractionation law for evaporation of magnesium is applicable to a wide range of bulk compositions. We discuss mass-fractionation laws and the implications of the measured fractionation behavior of magnesium isotopes for 26Al-26Mg chronology.

  7. Reaction Mechanisms of Magnesium Potassium Phosphate Cement and its Application

    NASA Astrophysics Data System (ADS)

    Qiao, Fei

    Magnesium potassium phosphate cement (MKPC) is a kind of cementitious binder in which the chemical bond is formed via a heterogeneous acid-base reaction between dead burned magnesia powder and potassium phosphate solution at room temperature. Small amount of boron compounds can be incorporated in the cement as a setting retarder. The final reaction product of MgO-KH2PO4-H 2O ternary system is identified as magnesium potassium phosphate hexahydrate, MgKPO4·6H2O. However, the mechanisms and procedures through which this crystalline product is formed and the conditions under which the crystallization process would be influenced are not yet clear. Understanding of the reaction mechanism of the system is helpful for developing new methodologies to control the rapid reaction process and furthermore, to adjust the phase assemblage of the binder, and to enhance the macroscopic properties. This study is mainly focused on the examination of the reaction mechanism of MKPC. In addition, the formulation optimization, microstructure characterization and field application in rapid repair are also systematically studied. The chemical reactions between magnesia and potassium dihydrogen phosphate are essentially an acid-base reaction with strong heat release, the pH and temperature variation throughout the reaction process could provide useful information to disclose the different stages in the reaction. However, it would be very difficult to conduct such tests on the cement paste due to the limited water content and fast setting. In the current research, the reaction mechanism of MKPC is investigated on the diluted MKPC system through monitoring the pH and temperature development, identification of the solid phase formed, and measurement of the ionic concentration of the solution. The reaction process can be explained as follows: when magnesia and potassium phosphate powder are mixed with water, phosphate is readily dissolved, which is instantly followed by the dissociation of

  8. Mechanism of heterogeneous reaction of carbonyl sulfide on magnesium oxide.

    PubMed

    Liu, Yongchun; He, Hong; Xu, Wenqing; Yu, Yunbo

    2007-05-24

    Heterogeneous reaction of carbonyl sulfide (OCS) on magnesium oxide (MgO) under ambient conditions was investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), quadrupole mass spectrometer (QMS), and density functional theory (DFT) calculations. It reveals that OCS can be catalytically hydrolyzed by surface hydroxyl on MgO to produce carbon dioxide (CO2) and hydrogen sulfide (H2S), and then H2S can be further catalytically oxidized by surface oxygen or gaseous oxygen on MgO to form sulfite (SO3(2-)) and sulfate (SO4(2-)). Hydrogen thiocarbonate (HSCO2-) was found to be the crucial intermediate. Surface hydrogen sulfide (HS), sulfur dioxide (SO2), and surface sulfite (SO3(2-)) were also found to be intermediates for the formation of sulfate. Furthermore, the surface hydroxyl contributes not only to the formation of HSCO2- but also to HSCO2- decomposition. On the basis of experimental results, the heterogeneous reaction mechanism of OCS on MgO was discussed.

  9. Impacts of diffusive transport on carbonate mineral formation from magnesium silicate-CO2-water reactions.

    PubMed

    Giammar, Daniel E; Wang, Fei; Guo, Bin; Surface, J Andrew; Peters, Catherine A; Conradi, Mark S; Hayes, Sophia E

    2014-12-16

    Reactions of CO2 with magnesium silicate minerals to precipitate magnesium carbonates can result in stable carbon sequestration. This process can be employed in ex situ reactors or during geologic carbon sequestration in magnesium-rich formations. The reaction of aqueous CO2 with the magnesium silicate mineral forsterite was studied in systems with transport controlled by diffusion. The approach integrated bench-scale experiments, an in situ spectroscopic technique, and reactive transport modeling. Experiments were performed using a tube packed with forsterite and open at one end to a CO2-rich solution. The location and amounts of carbonate minerals that formed were determined by postexperiment characterization of the solids. Complementing this ex situ characterization, (13)C NMR spectroscopy tracked the inorganic carbon transport and speciation in situ. The data were compared with the output of reactive transport simulations that accounted for diffusive transport processes, aqueous speciation, and the forsterite dissolution rate. All three approaches found that the onset of magnesium carbonate precipitation was spatially localized about 1 cm from the opening of the forsterite bed. Magnesite was the dominant reaction product. Geochemical gradients that developed in the diffusion-limited zones led to locally supersaturated conditions at specific locations even while the volume-averaged properties of the system remained undersaturated.

  10. Constraining magnesium cycling in marine sediments using magnesium isotopes

    NASA Astrophysics Data System (ADS)

    Higgins, J. A.; Schrag, D. P.

    2010-09-01

    Magnesium concentrations in deep-sea sediment pore-fluids typically decrease down core due to net precipitation of dolomite or clay minerals in the sediments or underlying crust. To better characterize and differentiate these processes, we have measured magnesium isotopes in pore-fluids and sediment samples from Ocean Drilling Program sites (1082, 1086, 1012, 984, 1219, and 925) that span a range of oceanographic settings. At all sites, magnesium concentrations decrease with depth. At sites where diagenetic reactions are dominated by the respiration of organic carbon, pore-fluid δ 26Mg values increase with depth by as much as 2‰. Because carbonates preferentially incorporate 24Mg (low δ 26Mg), the increase in pore-fluid δ 26Mg values at these sites is consistent with the removal of magnesium in Mg-carbonate (dolomite). In contrast, at sites where the respiration of organic carbon is not important and/or weatherable minerals are abundant, pore-fluid δ 26Mg values decrease with depth by up to 2‰. The decline in pore-fluid δ 26Mg at these sites is consistent with a magnesium sink that is isotopically enriched relative to the pore-fluid. The identity of this enriched magnesium sink is likely clay minerals. Using a simple 1D diffusion-advection-reaction model of pore-fluid magnesium, we estimate rates of net magnesium uptake/removal and associated net magnesium isotope fractionation factors for sources and sinks at all sites. Independent estimates of magnesium isotope fractionation during dolomite precipitation from measured δ 26Mg values of dolomite samples from sites 1082 and 1012 are very similar to modeled net fractionation factors at these sites, suggesting that local exchange of magnesium between sediment and pore-fluid at these sites can be neglected. Our results indicate that the magnesium incorporated in dolomite is 2.0-2.7‰ depleted in δ 26Mg relative to the precipitating fluid. Assuming local exchange of magnesium is minor at the rest of the

  11. Magnesium basics

    PubMed Central

    Ketteler, Markus

    2012-01-01

    As a cofactor in numerous enzymatic reactions, magnesium fulfils various intracellular physiological functions. Thus, imbalance in magnesium status—primarily hypomagnesaemia as it is seen more often than hypermagnesaemia—might result in unwanted neuromuscular, cardiac or nervous disorders. Measuring total serum magnesium is a feasible and affordable way to monitor changes in magnesium status, although it does not necessarily reflect total body magnesium content. The following review focuses on the natural occurrence of magnesium and its physiological function. The absorption and excretion of magnesium as well as hypo- and hypermagnesaemia will be addressed. PMID:26069819

  12. Thermal analysis of magnesium reactions with nitrogen/oxygen gas mixtures.

    PubMed

    Chunmiao, Yuan; Lifu, Yu; Chang, Li; Gang, Li; Shengjun, Zhong

    2013-09-15

    The thermal behavior and kinetic parameters of magnesium powder subjected to a nitrogen-rich atmosphere was investigated in thermogravimetric (TG) and differential scanning calorimeter (DSC) experiments with oxygen/nitrogen mixtures heated at rates of 5, 10, 15, and 20 °C/min. At higher temperature increase rates, the observed oxidation or nitridation steps shifted toward higher temperatures. The comparison of mass gain and heat of reaction in different nitrogen concentrations is helpful in interpreting the inerting effect of nitrogen on magnesium powder explosion in closed vessels. Activation energies for oxidation in air calculated by the Kissinger-Akahira-Sunose (KAS) method are generally consistent with previously published reports, but the method was not successful for the entire nitridation process. The change of activation energy with temperature was related to protective properties of the corresponding coating layer at particle surfaces. Two main coating layer growth processes were found in magnesium oxidation and nitridation using a modified Dreizin method which was also employed to determine activation energy for both magnesium oxidation and nitridation. For magnesium powder oxidation, activation energy calculated by the Dreizin method was close to that by KAS. Variation in activation energies was a function of different mechanisms inherent in the two methods.

  13. The analysis of magnesium oxide hydration in three-phase reaction system

    SciTech Connect

    Tang, Xiaojia; Guo, Lin; Chen, Chen; Liu, Quan; Li, Tie; Zhu, Yimin

    2014-05-01

    In order to investigate the magnesium oxide hydration process in gas–liquid–solid (three-phase) reaction system, magnesium hydroxide was prepared by magnesium oxide hydration in liquid–solid (two-phase) and three-phase reaction systems. A semi-empirical model and the classical shrinking core model were used to fit the experimental data. The fitting result shows that both models describe well the hydration process of three-phase system, while only the semi-empirical model right for the hydration process of two-phase system. The characterization of the hydration product using X-Ray diffraction (XRD) and scanning electron microscope (SEM) was performed. The XRD and SEM show hydration process in the two-phase system follows common dissolution/precipitation mechanism. While in the three-phase system, the hydration process undergo MgO dissolution, Mg(OH){sub 2} precipitation, Mg(OH){sub 2} peeling off from MgO particle and leaving behind fresh MgO surface. - Graphical abstract: There was existence of a peeling-off process in the gas–liquid–solid (three-phase) MgO hydration system. - Highlights: • Magnesium oxide hydration in gas–liquid–solid system was investigated. • The experimental data in three-phase system could be fitted well by two models. • The morphology analysis suggested that there was existence of a peel-off process.

  14. Production of magnesium metal

    DOEpatents

    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.

  15. Interdiffusion and reaction between pure magnesium and aluminum alloy 6061

    DOE PAGES

    Kammerer, C. C.; Fu, Mian; Zhou, Le; ...

    2015-06-01

    Using solid-to-solid couples investigation, this study characterized the reaction products evolved and quantified the diffusion kinetics when pure Mg bonded to AA6061 is subjected to thermal treatment at 300°C for 720 hours, 350°C for 360 hours, and 400°C for 240 hours. Characterization techniques include optical microscopy, scanning electron microscopy with X-ray energy dispersive spectroscopy, and transmission electron microscopy. Parabolic growth constants were determined for γ-Mg17Al12, β-Mg2Al3, and the elusive ε-phase. Similarly, the average effective interdiffusion coefficients of major constituents were calculated for Mg (ss), γ-Mg17Al12, β-Mg2Al3, and AA6061. The activation energies and pre-exponential factors for both parabolic growth constant andmore » average effective interdiffusion coefficients were computed using the Arrhenius relationship. The activation energy for growth of γ-Mg17Al12 was significantly higher than that for β-Mg2Al3 while the activation energy for interdiffusion of γ-Mg17Al12 was only slightly higher than that for β-Mg2Al3. As a result, comparisons are made between the results of this study and those of diffusion studies between pure Mg and pure Al to examine the influence of alloying additions in AA6061.« less

  16. Interdiffusion and reaction between pure magnesium and aluminum alloy 6061

    SciTech Connect

    Kammerer, C. C.; Fu, Mian; Zhou, Le; Keiser, Jr., Dennis D.; Sohn, Yong Ho

    2015-06-01

    Using solid-to-solid couples investigation, this study characterized the reaction products evolved and quantified the diffusion kinetics when pure Mg bonded to AA6061 is subjected to thermal treatment at 300°C for 720 hours, 350°C for 360 hours, and 400°C for 240 hours. Characterization techniques include optical microscopy, scanning electron microscopy with X-ray energy dispersive spectroscopy, and transmission electron microscopy. Parabolic growth constants were determined for γ-Mg17Al12, β-Mg2Al3, and the elusive ε-phase. Similarly, the average effective interdiffusion coefficients of major constituents were calculated for Mg (ss), γ-Mg17Al12, β-Mg2Al3, and AA6061. The activation energies and pre-exponential factors for both parabolic growth constant and average effective interdiffusion coefficients were computed using the Arrhenius relationship. The activation energy for growth of γ-Mg17Al12 was significantly higher than that for β-Mg2Al3 while the activation energy for interdiffusion of γ-Mg17Al12 was only slightly higher than that for β-Mg2Al3. As a result, comparisons are made between the results of this study and those of diffusion studies between pure Mg and pure Al to examine the influence of alloying additions in AA6061.

  17. Reaction pathways for hydrogen desorption from magnesium hydride/hydroxide composites: bulk and interface effects.

    PubMed

    Leardini, F; Ares, J R; Bodega, J; Fernández, J F; Ferrer, I J; Sánchez, C

    2010-01-21

    This manuscript investigates the thermal desorption behaviour of MgH(2)/Mg(OH)(2) composites by means of thermal desorption spectroscopy. Besides the H(2)O and H(2) desorption events due to Mg(OH)(2) dehydration and MgH(2) decomposition reactions, respectively, two additional H(2) desorption peaks arise at lower temperatures. These peaks are related to solid-state reactions between magnesium hydride and magnesium hydroxide through different channels. The low temperature H(2) peak ( approximately 150 degrees C) is related to reaction between a H atom diffusing from MgH(2) and a surface OH group, whereas the intermediate temperature H(2) peak ( approximately 350 degrees C) is due to an interface reaction between the hydride and the hydroxide. The present work supports the theory that the onset of the H(2) desorption coming from MgH(2) decomposition is controlled by an incubation process, consisting in the formation of catalytically active vacancies at the MgO/Mg(OH)(2) surface by dehydration. Possible ways to improve the H(2) desorption kinetics from MgH(2) are discussed in the light of the results obtained.

  18. Calcium-Magnesium-Aluminosilicate (CMAS) Reactions and Degradation Mechanisms of Advanced Environmental Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Ahlborg, Nadia L.; Zhu, Dongming

    2013-01-01

    The thermochemical reactions between calcium-magnesium-aluminosilicate- (CMAS-) based road sand and several advanced turbine engine environmental barrier coating (EBC) materials were studied. The phase stability, reaction kinetics and degradation mechanisms of rare earth (RE)-silicates Yb2SiO5, Y2Si2O7, and RE-oxide doped HfO2 and ZrO2 under the CMAS infiltration condition at 1500 C were investigated, and the microstructure and phase characteristics of CMAS-EBC specimens were examined using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Experimental results showed that the CMAS dissolved RE-silicates to form crystalline, highly non-stoichiometric apatite phases, and in particular attacking the silicate grain boundaries. Cross-section images show that the CMAS reacted with specimens and deeply penetrated into the EBC grain boundaries and formed extensive low-melting eutectic phases, causing grain boundary recession with increasing testing time in the silicate materials. The preliminary results also showed that CMAS reactions also formed low melting grain boundary phases in the higher concentration RE-oxide doped HfO2 systems. The effect of the test temperature on CMAS reactions of the EBC materials will also be discussed. The faster diffusion exhibited by apatite and RE-doped oxide phases and the formation of extensive grain boundary low-melting phases may limit the CMAS resistance of some of the environmental barrier coatings at high temperatures.

  19. Temperature dependence of the heterogeneous reaction of carbonyl sulfide on magnesium oxide.

    PubMed

    Liu, Yongchun; He, Hong; Ma, Qingxin

    2008-04-03

    The experimental determination of rate constants for atmospheric reactions and how these rate constants vary with temperature remain a crucially important part of atmosphere science. In this study, the temperature dependence of the heterogeneous reaction of carbonyl sulfide (COS) on magnesium oxide (MgO) has been investigated using a Knudsen cell reactor and a temperature-programmed reaction apparatus. We found that the adsorption and the heterogeneous reaction are sensitive to temperature. The initial uptake coefficients (gammat(Ini)) of COS on MgO decrease from 1.07 +/- 0.71 x 10-6 to 4.84 +/- 0.60 x 10-7 with the increasing of temperature from 228 to 300 K, and the steady state uptake coefficients (gammat(SS)) increase from 5.31 +/- 0.06 x 10-8 to 1.68 +/- 0.41 x 10-7 with the increasing of temperature from 240 to 300 K. The desorption rate constants (kdes) were also found to increase slightly with the enhancement of temperature. The empirical formula between the uptake coefficients, desorption rate constants and temperature described in the form of Arrhenius expression were obtained. The activation energies for the heterogeneous reaction and desorption of COS on MgO were measured to be 11.02 +/- 0.34 kJ.mol-1 and 6.30 +/- 0.81 kJ.mol-1, respectively. The results demonstrate that the initial uptake of COS on MgO is mainly contributed by an adsorption process and the steady state uptake is due to a catalytic reaction. The environmental implication was also discussed.

  20. Novel palladium complex-catalyzed reaction of magnesium amides with allylic electrophiles

    SciTech Connect

    Dzhemilev, U.M.; Ibragimov, A.G.; Minsker, D.L.; Muslukhov, R.R.

    1987-08-20

    In order to develop an efficient method for the synthesis of higher order unsaturated tertiary amines, and also to explore a new method for the formation of C-N bonds, they have investigated the transition metal complex-catalyzed reaction of magnesium amides with electrophiles; the electrophiles selected for study included allyl ethers and esters, as well as sulfones, sulfides and quaternized allylamines. The effects of the nature and structure of the catalyst components, as well as of the reaction conditions, on product yield were examined in the case of the reaction of diethyl (bromomagnesium)amine with diallyl ether, and revealed that the highest yield of diethylallyl-amine (I) was achieved using Pd(acac)/sub 2/ (3-5 mole %) and Ph/sub 3/P (1:2) as catalyst in THF solution at 50/sup 0/C for 5 h. Other transition metal (Ni, Fe, Zr, Ti, Cu) compounds were also examined as catalysts, but the yield of (I) did not exceed 15% with these compounds. Bimetallic catalysts based on Zr (Cp/sub 2/ZrCl, Py/sub 2/ZrCl/sub 6/, (RO)/sub 4/Zr) and Ni (Ni(acac)/sub 2/ and NiCl/sub 2/) were successful in forming (I) from diethyl (bromomagnesium)amine and diallyl ether in 60% yield.

  1. Measurement of pion double charge exchange on carbon-13, carbon-14, magnesium-26, and iron-56

    SciTech Connect

    Seidl, P.A.

    1985-02-01

    Cross sections for the /sup 13,14/C,/sup 26/Mg,/sup 56/Fe(..pi../sup +/,..pi../sup -/)/sup 13,14/O,/sup 26/Si,/sup 56/Ni reactions were measured with the Energetic Pion Channel and Spectrometer at the Clinton P. Anderson Meson Physics Facility for 120 less than or equal to T/sub ..pi../ less than or equal to 292 MeV and 0 less than or equal to theta less than or equal to 50. The double isobaric analog states (DIAS) are of primary interest. In addition, cross sections for transitions to /sup 14/O(0/sup +/, 5.92 MeV), /sup 14/O(2/sup +/, 7.77 MeV), /sup 56/Ni(gs), /sup 13/O(gs), and /sup 13/O(4.21 MeV) are presented. The /sup 13/O(4.21 MeV) state is postulated to have J/sup ..pi../ = 1/2/sup -/. The data are compared to previously measured double-charge-exchange cross sections on other nuclei, and the systematics of double charge exchange on T greater than or equal to 1 target nuclei leading to the DIAS are studied. Near the ..delta../sub 33/ resonance, cross sections for the DIAS transitions are in disagreement with calculations in which the reaction is treated as sequential charge exchange through the free pion-nucleon amplitude, while for T/sub ..pi../ > 200 MeV the anomalous features of the 164 MeV data are not apparent. This is evidence for significant higher order contributions to the double-charge-exchange amplitude near the reasonable energy. Two theoretical approaches that include two nucleon processes are applied to the DIAS data. 64 references.

  2. Experimental and theoretical study of hydrogen thiocarbonate for heterogeneous reaction of carbonyl sulfide on magnesium oxide.

    PubMed

    Liu, Yongchun; He, Hong

    2009-04-09

    In situ diffuse reflectance infrared Fourier transform spectroscopy combined with derivative spectroscopy analysis, two-dimensional correlation spectroscopy analysis, and quantum chemical calculations were used to investigate the infrared absorbance assignment and the molecular structure of hydrogen thiocarbonate on magnesium oxide. The bands at 1283 and 1257 cm(-1), which had the typical characteristic of intermediate, were observed in experiments for the heterogeneous reaction of COS on MgO. On the basis of two-dimensional correlation spectroscopy analysis and quantum chemical calculations, the band at 1283 cm(-1) was assigned to the v(s) band of bridged thiocarbonate which formed on the two neighboring Mg atoms in the (100) face of MgO crystal, and the band at 1257 cm(-1) was the v(s) band of monodentate thiocarbonate on MgO. The v(as)(OCO) band of thiocarbonates was invisible in the experiment due to their weak absorbance and the interruption of surface carbonate. The formation mechanism of thiocarbonates is proposed, which occurred through a nucleophilic attack of preadsorbed COS by surface -OH groups followed by hydrogen atom transfer from the -OH group to the sulfur atom of preadsorbed COS. The activation energy for the intramolecular proton-transfer reaction of bridged thiocarbonate was calculated to be 18.52 kcal x mol(-1) at the B3LYP/6-31+G(d,p) level of theory.

  3. Method for production of magnesium

    DOEpatents

    Diaz, A.F.; Howard, J.B.; Modestino, A.J.; Peters, W.A.

    1998-07-21

    A continuous process for the production of elemental magnesium is described. Magnesium is made from magnesium oxide and a light hydrocarbon gas. In the process, a feed stream of the magnesium oxide and gas is continuously fed into a reaction zone. There the magnesium oxide and gas are reacted at a temperature of about 1400 C or greater in the reaction zone to provide a continuous product stream of reaction products, which include elemental magnesium. The product stream is continuously quenched after leaving the reaction zone, and the elemental magnesium is separated from other reaction products. 12 figs.

  4. Method for production of magnesium

    DOEpatents

    Diaz, Alexander F.; Howard, Jack B.; Modestino, Anthony J.; Peters, William A.

    1998-01-01

    A continuous process for the production of elemental magnesium is described. Magnesium is made from magnesium oxide and a light hydrocarbon gas. In the process, a feed stream of the magnesium oxide and gas is continuously fed into a reaction zone. There the magnesium oxide and gas are reacted at a temperature of about 1400.degree. C. or greater in the reaction zone to provide a continuous product stream of reaction products, which include elemental magnesium. The product stream is continuously quenched after leaving the reaction zone, and the elemental magnesium is separated from other reaction products.

  5. Study of the 26Alm (d ,p )27Al Reaction and the Influence of the 26 0+ Isomer on the Destruction of 26Al in the Galaxy

    NASA Astrophysics Data System (ADS)

    Almaraz-Calderon, S.; Rehm, K. E.; Gerken, N.; Avila, M. L.; Kay, B. P.; Talwar, R.; Ayangeakaa, A. D.; Bottoni, S.; Chen, A. A.; Deibel, C. M.; Dickerson, C.; Hanselman, K.; Hoffman, C. R.; Jiang, C. L.; Kuvin, S. A.; Nusair, O.; Pardo, R. C.; Santiago-Gonzalez, D.; Sethi, J.; Ugalde, C.

    2017-08-01

    The existence of 26 (t1 /2=7.17 ×105 yr ) in the interstellar medium provides a direct confirmation of ongoing nucleosynthesis in the Galaxy. The presence of a low-lying 0+ isomer (26m ), however, severely complicates the astrophysical calculations. We present for the first time a study of the 26Al m(d ,p ) 27Al reaction using an isomeric 26Al beam. The selectivity of this reaction allowed the study of ℓ=0 transfers to T =1 /2 , and T =3 /2 states in 27Al. Mirror symmetry arguments were then used to constrain the 26Al m(p ,γ ) 27Si reaction rate and provide an experimentally determined upper limit of the rate for the destruction of isomeric 26Al via radiative proton capture reactions, which is expected to dominate the destruction path of 26Alm in asymptotic giant branch stars, classical novae, and core collapse supernovae.

  6. Calcium-aluminum-rich inclusions with fractionation and unidentified nuclear effects (FUN CAIs): II. Heterogeneities of magnesium isotopes and 26Al in the early Solar System inferred from in situ high-precision magnesium-isotope measurements

    NASA Astrophysics Data System (ADS)

    Park, Changkun; Nagashima, Kazuhide; Krot, Alexander N.; Huss, Gary R.; Davis, Andrew M.; Bizzarro, Martin

    2017-03-01

    Calcium-aluminum-rich inclusions with isotopic mass fractionation effects and unidentified nuclear isotopic anomalies (FUN CAIs) have been studied for more than 40 years, but their origins remain enigmatic. Here we report in situ high precision measurements of aluminum-magnesium isotope systematics of FUN CAIs by secondary ion mass spectrometry (SIMS). Individual minerals were analyzed in six FUN CAIs from the oxidized CV3 carbonaceous chondrites Axtell (compact Type A CAI Axtell 2271) and Allende (Type B CAIs C1 and EK1-4-1, and forsterite-bearing Type B CAIs BG82DH8, CG-14, and TE). Most of these CAIs show evidence for excess 26Mg due to the decay of 26Al. The inferred initial 26Al/27Al ratios [(26Al/27Al)0] and the initial magnesium isotopic compositions (δ26Mg0) calculated using an exponential law with an exponent β of 0.5128 are (3.1 ± 1.6) × 10-6 and 0.60 ± 0.10‰ (Axtell 2271), (3.7 ± 1.5) × 10-6 and -0.20 ± 0.05‰ (BG82DH8), (2.2 ± 1.1) × 10-6 and -0.18 ± 0.05‰ (C1), (2.3 ± 2.4) × 10-5 and -2.23 ± 0.37‰ (EK1-4-1), (1.5 ± 1.1) × 10-5 and -0.42 ± 0.08‰ (CG-14), and (5.3 ± 0.9) × 10-5 and -0.05 ± 0.08‰ (TE) with 2σ uncertainties. We infer that FUN CAIs recorded heterogeneities of magnesium isotopes and 26Al in the CAI-forming region(s). Comparison of 26Al-26Mg systematics, stable isotope (oxygen, magnesium, calcium, and titanium) and trace element studies of FUN and non-FUN igneous CAIs indicates that there is a continuum among these CAI types. Based on these observations and evaporation experiments on CAI-like melts, we propose a generic scenario for the origin of igneous (FUN and non-FUN) CAIs: (i) condensation of isotopically normal solids in an 16O-rich gas of approximately solar composition; (ii) formation of CAI precursors by aggregation of these solids together with variable abundances of isotopically anomalous grains-possible carriers of unidentified nuclear (UN) effects; and (iii) melt evaporation of these precursors

  7. Magnesium absorption in human subjects from leafy vegetables, intrinsically labeled with stable 26Mg.

    PubMed

    Schwartz, R; Spencer, H; Welsh, J J

    1984-04-01

    Collards, turnip greens, leaf lettuce, and spinach, grown in nutrient solution so that their Mg content was 80 to 90% 26Mg, were tested in ambulant male volunteers stabilized on a constant metabolic diet. The freeze-dried vegetables were incorporated in bran muffins in which the vegetables replaced part of the bran. Bran muffins without vegetables were consumed for breakfast each day. They were also used as a standard test meal to which the vegetable muffins were compared. All subjects participated in three consecutive isotope absorption tests: one of the standard test meal and two of the vegetables. The standard test was carried out after at least 30 days on the controlled diet. Subsequent tests of vegetables followed at 4-wk intervals. Each test meal contained 30 microCi 28MgCl2 and 50 mg stable 26Mg, the latter either as the intrinsic label of a test vegetable or as 26MgCl2 in solution taken with the standard bran muffins. Net absorption of both isotopes was measured to establish exchangeability and to determine relative Mg absorption from the vegetables. Exchangeability was 90% or higher from all meals tested. Relative Mg absorption was highest from collards and least from the standard test meal. Net absorption values ranged from 40 to 60%.

  8. Magnesium absorption in human subjects from leafy vegetables, intrinsically labeled with stable /sup 26/Mg

    SciTech Connect

    Schwartz, R.; Spencer, H.; Welsh, J.J.

    1984-04-01

    Collards, turnip greens, leaf lettuce, and spinach, grown in nutrient solution so that their Mg content was 80 to 90% /sup 26/Mg, were tested in ambulant male volunteers stabilized on a constant metabolic diet. The freeze-dried vegetables were incorporated in bran muffins in which the vegetables replaced part of the bran. Bran muffins without vegetables were consumed for breakfast each day. They were also used as a standard test meal to which the vegetable muffins were compared. All subjects participated in three consecutive isotope absorption tests: one of the standard test meal and two of the vegetables. The standard test was carried out after at least 30 days on the controlled diet. Subsequent tests of vegetables followed at 4-wk intervals. Each test meal contained 30 microCi /sup 28/MgCl2 and 50 mg stable /sup 26/Mg, the latter either as the intrinsic label of a test vegetable or as /sup 26/MgCl/sub 2/ in solution taken with the standard bran muffins. Net absorption of both isotopes was measured to establish exchangeability and to determine relative Mg absorption from the vegetables. Exchangeability was 90% or higher from all meals tested. Relative Mg absorption was highest from collards and least from the standard test meal. Net absorption values ranged from 40 to 60%.

  9. Kinetics of intercalation of fluorescent probes in magnesium-aluminium layered double hydroxide within a multiscale reaction-diffusion framework

    NASA Astrophysics Data System (ADS)

    Saliba, Daniel; Al-Ghoul, Mazen

    2016-11-01

    We report the synthesis of magnesium-aluminium layered double hydroxide (LDH) using a reaction-diffusion framework (RDF) that exploits the multiscale coupling of molecular diffusion with chemical reactions, nucleation and growth of crystals. In an RDF, the hydroxide anions are allowed to diffuse into an organic gel matrix containing the salt mixture needed for the precipitation of the LDH. The chemical structure and composition of the synthesized magnesium-aluminium LDHs are determined using powder X-ray diffraction (PXRD), thermo-gravimetric analysis, differential scanning calorimetry, solid-state nuclear magnetic resonance (SSNMR), Fourier transform infrared and energy dispersive X-ray spectroscopy. This novel technique also allows the investigation of the mechanism of intercalation of some fluorescent probes, such as the neutral three-dimensional rhodamine B (RhB) and the negatively charged two-dimensional 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS), using in situ steady-state fluorescence spectroscopy. The incorporation of these organic dyes inside the interlayer region of the LDH is confirmed via fluorescence microscopy, solid-state lifetime, SSNMR and PXRD. The activation energies of intercalation of the corresponding molecules (RhB and HPTS) are computed and exhibit dependence on the geometry of the involved probe (two or three dimensions), the charge of the fluorescent molecule (anionic, cationic or neutral) and the cationic ratio of the corresponding LDH. This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.

  10. Diagenesis-inspired reaction of magnesium ions with surface enamel mineral modifies properties of human teeth.

    PubMed

    Abdallah, Mohamed-Nur; Eimar, Hazem; Bassett, David C; Schnabel, Martin; Ciobanu, Ovidiu; Nelea, Valentin; McKee, Marc D; Cerruti, Marta; Tamimi, Faleh

    2016-06-01

    Mineralized tissues such as teeth and bones consist primarily of highly organized apatitic calcium-phosphate crystallites within a complex organic matrix. The dimensions and organization of these apatite crystallites at the nanoscale level determine in part the physical properties of mineralized tissues. After death, geological processes such as diagenesis and dolomitization can alter the crystallographic properties of mineralized tissues through cycles of dissolution and re-precipitation occurring in highly saline environments. Inspired by these natural exchange phenomena, we investigated the effect of hypersalinity on tooth enamel. We discovered that magnesium ions reacted with human tooth enamel through a process of dissolution and re-precipitation, reducing enamel crystal size at the surface of the tooth. This change in crystallographic structure made the teeth harder and whiter. Salt-water rinses have been used for centuries to ameliorate oral infections; however, our discovery suggests that this ancient practice could have additional unexpected benefits. Here we describe an approach inspired by natural geological processes to modify the properties of a biomineral - human tooth enamel. In this study we showed that treatment of human tooth enamel with solutions saturated with magnesium induced changes in the nanocrystals at the outer surface of the protective enamel layer. As a consequence, the physical properties of the tooth were modified; tooth microhardness increased and the color shade became whiter, thus suggesting that this method could be used as a clinical treatment to improve dental mechanical properties and esthetics. Such an approach is simple and straightforward, and could also be used to develop new strategies to synthesize and modify biominerals for biomedical and industrial applications. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  11. The 28Si(p,t)26Si*(p) reaction and implications for the astrophysical 25Al(p,gamma)26Si reaction rate

    SciTech Connect

    Chipps, K.; Bardayan, Daniel W; Chae, K. Y.; Cizewski, J. A.; Kozub, R. L.; Liang, J Felix; Matei, Catalin; Moazen, Brian; Nesaraja, Caroline D; O'Malley, Patrick; Pain, S. D.; Peters, W. A.; Pittman, S. T.; Schmitt, Kyle; Smith, Michael Scott

    2010-10-01

    Several resonances in 25Al(p, )26Si have been studied via the 28Si(p,t)26Si reaction. Triton energies and angular distributions were measured using a segmented annular detector array. An additional silicon detector array was used to simultaneously detect the coincident protons emitted from the decay of states in 26Si above the proton threshold, in order to determine branching ratios. A resonance at 5927 4 keV has been experimentally confirmed as the first = 0 state above the proton threshold, with a proton branching ratio consistent with one.

  12. REACTION MECHANISMS OF MAGNESIUM SILICATES WITH CARBON DIOXIDE IN MICROWAVE FIELDS

    SciTech Connect

    William B. White; Michael R. Silsbee; B. Joe Kearns

    2004-02-18

    The objective of the investigation was to determine whether microwave fields would enhance the reactions of CO{sub 2} with silicates that are relevant to the sequestration of carbon dioxide. Three sets of experiments were conducted. (1) Serpentine and CO{sub 2} were reacted directly at one atmosphere pressure in a microwave furnace. Little reaction was observed. (2) Serpentine was dehydroxylated in a microwave furnace. The reaction was rapid, reaching completion in less than 30 minutes. A detailed investigation of this reaction produced an S-shaped kinetics curve, similar to the kinetics from dehydroxylating serpentine in a resistance furnace, but offset to 100 C lower temperature. This set of experiments clearly demonstrates the effect of microwaves for enhancing reaction kinetics. (3) Reactions of serpentine with alkaline carbonates and in acid solution were carried out in a microwave hydrothermal apparatus. There was a greatly enhanced decomposition of the serpentine in acid solution but, at the temperature and pressure of the reaction chamber (15 bars; 200 C) the carbonates did not react. Overall, microwave fields, as expected, enhance silicate reaction kinetics, but higher CO{sub 2} pressures are needed to accomplish the desired sequestration reactions.

  13. Comment on ``Properties of 26Mg and 26Si in the sd shell model and the determination of the 25Al(p,γ)26Si reaction rate''

    NASA Astrophysics Data System (ADS)

    Chipps, K. A.; Bardayan, D. W.; Chae, K. Y.; Cizewski, J. A.; Kozub, R. L.; Liang, J. F.; Matei, C.; O'Malley, P. D.; Pain, S. D.; Peters, W. A.; Pittman, S. T.; Smith, M. S.

    2011-11-01

    A recent discussion of theoretical work on the 25Al(p,γ)26Si astrophysical reaction rate [W.A. Richter, B. Alex Brown, A. Signoracci and M. Wiescher, Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.83.065803 83, 065803 (2011)] omits some current and relevant experimental information in forming its scientific conclusions. Accounting for this new information has the potential to significantly alter the reaction rate derived in the paper.

  14. High-precision (p,t) reaction to determine {sup 25}Al(p,{gamma}){sup 26}Si reaction rates

    SciTech Connect

    Matic, A.; Berg, A. M. van den; Harakeh, M. N.; Woertche, H. J.; Berg, G. P. A.; Couder, M.; Goerres, J.; LeBlanc, P.; O'Brien, S.; Wiescher, M.; Fujita, K.; Hatanaka, K.; Sakemi, Y.; Shimizu, Y.; Tameshige, Y.; Tamii, A.; Yosoi, M.; Adachi, T.; Fujita, Y.; Shimbara, Y.

    2010-08-15

    Since the identification of ongoing {sup 26}Al production in the universe, the reaction sequence {sup 24}Mg(p,{gamma}){sup 25}Al({beta}{sup +{nu}}){sup 25}Mg(p,{gamma}){sup 26}Al has been studied intensively. At temperatures where the radiative capture on {sup 25}Al (t{sub 1/2}=7.2 s) becomes faster than the {beta}{sup +} decay, the production of {sup 26}Al can be reduced due to the depletion of {sup 25}Al. To determine the resonances relevant for the {sup 25}Al(p,{gamma}){sup 26}Si bypass reaction, we measured the {sup 28}Si(p,t){sup 26}Si reaction with high-energy precision using the Grand Raiden spectrometer at the Research Center for Nuclear Physics, Osaka. Several new energy levels were found above the p threshold and for known states excitation energies were determined with smaller uncertainties. The calculated stellar rates of the bypass reaction agree well with previous results, suggesting that these rates are well established.

  15. Elastic scattering and neutron transfer of the 26Mg + 13C reaction

    NASA Astrophysics Data System (ADS)

    McCleskey, Matthew; Alharby, A.; Banu, A.; Goldberg, V. Z.; McCleskey, E.; Roeder, B. T.; Spiridon, A.; Trache, L.; Tribble, R. E.

    2013-10-01

    Direct proton capture on 26Si is of interest for its role in the destruction of 26Si that would otherwise be available to β+ decay into 26mAl. This is part of the network of reactions that influence the production and destruction of the important astrophysical observable 26Al. The 13C(26Mg,27Mg)12C reaction at 12 MeV/nucleon has been measured at Texas A &M University Cyclotron Institute with the aim to determine ANC for 27P <--> p + 26Si via mirror symmetry. Details of the experiment as well as preliminary results will be presented. Present address: Faculty of Sciences, Physics Department, Princess Nora University Riyadh, Saudi Arabia.

  16. In vivo assessment of the host reactions to the biodegradation of the two novel magnesium alloys ZEK100 and AX30 in an animal model

    PubMed Central

    2012-01-01

    Background Most studies on biodegradable magnesium implants published recently use magnesium-calcium-alloys or magnesium-aluminum-rare earth-alloys. However, since rare earths are a mixture of elements and their toxicity is unclear, a reduced content of rare earths is favorable. The present study assesses the in vivo biocompatibility of two new magnesium alloys which have a reduced content (ZEK100) or contain no rare earths at all (AX30). Methods 24 rabbits were randomized into 4 groups (AX30 or ZEK100, 3 or 6 months, respectively) and cylindrical pins were inserted in their tibiae. To assess the biodegradation μCT scans and histological examinations were performed. Results The μCT scans showed that until month three ZEK100 degrades faster than AX30, but this difference is leveled out after 6 months. Histology revealed that both materials induce adverse host reactions and high numbers of osteoclasts in the recipient bone. The mineral apposition rates of both materials groups were high. Conclusions Both alloys display favorable degradation characteristics, but they induce adverse host reactions, namely an osteoclast-driven resorption of bone and a subsequent periosteal formation of new bone. Therefore, the biocompatibility of ZEK100 and AX30 is questionable and further studies, which should focus on the interactions on cellular level, are needed. PMID:22429539

  17. Experimental study of the astrophysically important 23Na(α ,p )26Mg and 23Na(α ,n )26Al reactions

    NASA Astrophysics Data System (ADS)

    Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.; Ayangeakaa, A. D.; Dickerson, C.; Hoffman, C. R.; Jiang, C. L.; Kay, B. P.; Lai, J.; Nusair, O.; Pardo, R. C.; Santiago-Gonzalez, D.; Talwar, R.; Ugalde, C.

    2016-12-01

    The 23Na(α ,p )26Mg and 23Na(α ,n )26Al reactions are important for our understanding of the 26Al abundance in massive stars. The aim of this work is to report on a direct and simultaneous measurement of these astrophysically important reactions using an active target system. The reactions were investigated in inverse kinematics using 4He as the active target gas in the detector. We measured the excitation functions in the energy range of about 2 to 6 MeV in the center of mass. We have found that the cross sections of the 23Na(α ,p )26Mg and the 23Na(α ,n )26Al reactions are in good agreement with previous experiments and with statistical-model calculations. The astrophysical reaction rate of the 23Na(α ,n )26Al reaction has been reevaluated and it was found to be larger than the recommended rate.

  18. ortho-Lithium/magnesium carboxylate-driven aromatic nucleophilic substitution reactions on unprotected naphthoic acids.

    PubMed

    Aissaoui, Regadia; Nourry, Arnaud; Coquel, Ariane; Dao, Thi Thanh Hà; Derdour, Aicha; Helesbeux, Jean-Jacques; Duval, Olivier; Castanet, Anne-Sophie; Mortier, Jacques

    2012-01-06

    Substitution of an ortho-fluoro or methoxy group in 1- and 2-naphthoic acids furnishing substituted naphthoic acids occurs in good to excellent yields upon reaction with alkyl/vinyl/aryl organolithium and Grignard reagents, in the absence of a metal catalyst without the need to protect the carboxyl (CO(2)H) group. This novel nucleophilic aromatic substitution is presumed to proceed via a precoordination of the organometallic with the substrate, followed by an addition/elimination.

  19. Mechanical properties of thermoelectric n-type magnesium silicide synthesized employing in situ spark plasma reaction sintering

    NASA Astrophysics Data System (ADS)

    Muthiah, Saravanan; Singh, R. C.; Pathak, B. D.; Dhar, Ajay

    2017-07-01

    Thermoelectric devices employing magnesium silicide (Mg2Si) offer an inexpensive and non-toxic solution for green energy generation compared to other existing conventional thermoelectric materials in the mid-temperature range. However, apart from the thermoelectric performance, their mechanical properties are equally important in order to avoid the catastrophic failure of their modules during actual operation. In the present study, we report the synthesis of Mg2Si co-doped with Bi and Sb employing in situ spark plasma reaction sintering and investigate its broad range of mechanical properties. The mechanical properties of the sintered co-doped Mg2Si suggest a significantly enhanced value of hardness ~5.4  ±  0.2 GPa and an elastic modulus ~142.5  ±  6 GPa with a fracture toughness of ~1.71  ±  0.1 MPa  √m. The thermal shock resistance, which is one of the most vital parameter for designing thermoelectric devices, was found to be ~300 W m-1, which is higher than most of the other existing state-of-the-art mid-temperature thermoelectric materials. The friction and wear characteristics of sintered co-doped Mg2Si have been reported for the first time, in order to realize the sustainability of their thermoelectric modules under actual hostile environmental conditions.

  20. Nickel-catalyzed cross-coupling reaction of aryl fluorides and chlorides with grignard reagents under nickel/magnesium bimetallic cooperation.

    PubMed

    Yoshikai, Naohiko; Mashima, Hiroko; Nakamura, Eiichi

    2005-12-28

    Nickel-catalyzed cross-coupling of Grignard reagents with aryl (poly)fluorides or (poly)chlorides can be achieved efficiently in the presence of a new triarylphosphine ligand bearing a nearby hydroxy group. The high reactivity and the unique chemoselectivity (ArF > ArOTf > ArSR) of the catalysis have been attributed to synergy of nickel and magnesium atoms preorganized on the ligand, as has been surmised on the basis of theoretical modeling of the reaction mechanism.

  1. 23Na (α,p )26Mg Reaction Rate at Astrophysically Relevant Energies

    NASA Astrophysics Data System (ADS)

    Howard, A. M.; Munch, M.; Fynbo, H. O. U.; Kirsebom, O. S.; Laursen, K. L.; Diget, C. Aa.; Hubbard, N. J.

    2015-07-01

    The production of 26Al in massive stars is sensitive to the 23Na (α,p )26Mg cross section. Recent experimental data suggest the currently recommended cross sections are underestimated by a factor of ˜40 . We present here differential cross sections for the 23Na (α,p )26Mg reaction measured in the energy range Ec .m .=1.7 - 2.5 MeV . Concurrent measurements of Rutherford scattering provide absolute normalizations that are independent of variations in target properties. Angular distributions are measured for both p0 and p1 permitting the determination of total cross sections. The results show no significant deviation from the statistical model calculations upon which the recommended rates are based. We therefore retain the previous recommendation without the increase in cross section and resulting stellar reaction rates by a factor of 40, impacting the 26Al yield from massive stars by more than a factor of 3.

  2. Quantitative study of solid-state acid-base reactions between polymorphs of flufenamic acid and magnesium oxide using X-ray powder diffraction.

    PubMed

    Chen, Xiaoming; Stowell, Joseph G; Morris, Kenneth R; Byrn, Stephen R

    2010-03-11

    The purpose of this study is to investigate solid-state acid-base reactions between polymorphs of flufenamic acid (FFA) and magnesium oxide (MgO) using X-ray powder diffraction (XRPD). Polymorphs of FFA were blended with MgO and stored under conditions of 96.5% RH and 89% RH at 40 degrees C. The disappearance of FFA and production of magnesium flufenamate were monitored by XRPD. It was observed that the reactions between FFA and MgO proceeded following the Jander equation. Form I of FFA is more reactive with MgO than Form III. Differential accessibility of reactive groups is hypothesized as one of the reasons that Form I is more reactive than Form III. It was noted that the reaction between FFA and MgO could be mitigated by adding another acidic excipient such as polyacrylic acid to prevent the acid-base reaction with FFA. The effectiveness of polyacrylic acid was impacted by the mixing order of the tertiary mixture. Mixing polyacrylic acid and MgO first provided the most significant protection. In conclusion, solid-state acid-base reactions could be investigated using XRPD. Different forms may have distinct reactivity. Acid-base reactions in the solid state could be mitigated through the addition of another "shielding" excipient. Copyright 2009 Elsevier B.V. All rights reserved.

  3. Ultrasound-assisted activation of zero-valent magnesium for nitrate denitrification: identification of reaction by-products and pathways.

    PubMed

    Ileri, Burcu; Ayyildiz, Onder; Apaydin, Omer

    2015-07-15

    Zero-valent magnesium (Mg(0)) was activated by ultrasound (US) in an aim to promote its potential use in water treatment without pH control. In this context, nitrate reduction was studied at batch conditions using various doses of magnesium powder and ultrasound power. While neither ultrasound nor zero-valent magnesium alone was effective for reducing nitrate in water, their combination removed up to 90% of 50 mg/L NO3-N within 60 min. The rate of nitrate reduction by US/Mg(0) enhanced with increasing ultrasonic power and magnesium dose. Nitrogen gas (N2) and nitrite (NO2(-)) were detected as the major reduction by-products, while magnesium hydroxide Mg(OH)2 and hydroxide ions (OH(-)) were identified as the main oxidation products. The results from SEM-EDS measurements revealed that the surface oxide level decreased significantly when the samples of Mg(0) particles were exposed to ultrasonic treatment. The surface passivation of magnesium particles was successfully minimized by mechanical forces of ultrasound, which in turn paved the way to sustain the catalyst activity toward nitrate reduction.

  4. Magnesium hydrides and the dearomatisation of pyridine and quinoline derivatives.

    PubMed

    Hill, Michael S; Kociok-Köhn, Gabriele; MacDougall, Dugald J; Mahon, Mary F; Weetman, Catherine

    2011-12-14

    Reactions of the β-diketiminato n-butyl magnesium complex, [HC{(Me)CN(2,6-(i)Pr(2)C(6)H(3))}(2)Mg(n)Bu], with a range of substituted pyridines and fused-ring quinolines in the presence of PhSiH(3) has been found to result in dearomatisation of the N-heterocyclic compounds. This reaction is proposed to occur through the formation of an unobserved N-heterocycle-coordinated magnesium hydride and subsequent hydride transfer via the C2-position of the heterocycle prior to hydride transfer to the C4-position and formation of thermodynamically-favoured magnesium 1,4-dihydropyridides. This reaction is kinetically suppressed for 2,6-dimethylpyridine while the kinetic product, the 1,2-dihydropyridide derivative, was isolated through reaction with 4-methylpyridine (4-methylpyridine), in which case the formation of the 1,4-dihyropyridide is prevented by the presence of the 4-methyl substituent. X-ray structures of the products of these reactions with 4-methylpyridine, 3,5-dimethylpyridine and iso-quinoline comprise a pseudo-tetrahedral magnesium centre while the regiochemistry of the particular dearomatisation reaction is determined by the substitution pattern of the N-heterocycle under observation. The compounds are all air-sensitive and exposure of the magnesium derivatives of dearomatised pyridine and 4-dimethylaminopyridine (DMAP) to air resulted in ligand rearomatisation and the formation of dimeric μ(2)-η(2)-η(2)-peroxomagnesium compounds which have also been subject to analysis by single crystal X-ray diffraction analysis. An unsuccessful extension of this chemistry to N-heterocycle hydrosilylation is suggested to be a consequence of the low basicity of the silane reagent in comparison to the pyridine substrates which effectively impedes any further interaction with the magnesium centres.

  5. Density functional investigations of electronic structure and dehydrogenation reactions of Al- and Si-substituted magnesium hydride.

    PubMed

    Kelkar, Tuhina; Pal, Sourav; Kanhere, Dilip G

    2008-04-21

    The effect on the hydrogen storage attributes of magnesium hydride (MgH(2)) of the substitution of Mg by varying fractions of Al and Si is investigated by an ab initio plane-wave pseuodopotential method based on density functional theory. Three supercells, namely, 2 x 2 x 2, 3 x 1 x 1 and 5 x 1 x 1 are used for generating configurations with varying amounts (fractions x=0.0625, 0.1, and 0.167) of impurities. The analyses of band structure and density of states (DOS) show that, when a Mg atom is replaced by Al, the band gap vanishes as the extra electron occupies the conduction band minimum. In the case of Si-substitution, additional states are generated within the band gap of pure MgH(2)-significantly reducing the gap in the process. The reduced band gaps cause the Mg--H bond to become more susceptible to dissociation. For all the fractions, the calculated reaction energies for the stepwise removal of H(2) molecules from Al- and Si-substituted MgH(2) are much lower than for H(2) removal from pure MgH(2). The reduced stability is also reflected in the comparatively smaller heats of formation (DeltaH(f)) of the substituted MgH(2) systems. Si causes greater destabilization of MgH(2) than Al for each x. For fractions x=0.167 of Al, x=0.1, 0.167 of Si (FCC) and x=0.0625, 0.1 of Si (diamond), DeltaH(f) is much less than that of MgH(2) substituted by a fraction x=0.2 of Ti (Y. Song, Z. X. Guo, R. Yang, Mat. Sc. & Eng. A 2004, 365, 73). Hence, we suggest the use of Al or Si instead of Ti as an agent for decreasing the dehydrogenation reaction and energy, consequently, the dehydrogenation temperature of MgH(2), thereby improving its potential as a hydrogen storage material.

  6. Expanding Mg-Zn hybrid chemistry: inorganic salt effects in addition reactions of organozinc reagents to trifluoroacetophenone and the implications for a synergistic lithium-magnesium-zinc activation.

    PubMed

    Armstrong, David R; Clegg, William; García-Álvarez, Pablo; Kennedy, Alan R; McCall, Matthew D; Russo, Luca; Hevia, Eva

    2011-07-18

    Numerous organic transformations rely on organozinc compounds made through salt-metathesis (exchange) reactions from organolithium or Grignard reagents with a suitable zinc precursor. By combining X-ray crystallography, NMR spectroscopy and DFT calculations, this study sheds new light on the constitution of the organometallic species involved in this important synthetic tool. Investigations into the metathesis reactions of equimolar amounts of Grignard reagents (RMgX) and ZnCl(2) in THF led to the isolation of novel magnesium-zinc hybrids, [{(thf)(2)Mg(μ-Cl)(3)ZnR}(2)] (R=Et, tBu, nBu or o-OMe-C(6)H(4)), which exhibit an unprecedented structural motif in mixed magnesium-zinc chemistry. Furthermore, theoretical modelling of the reaction of EtMgCl with ZnCl(2) reveals that formation of the mixed-metal compound is thermodynamically preferred to that of the expected homometallic products, RZnCl and MgCl(2). This study also assesses the alkylating ability of hybrid 3 towards the sensitive ketone trifluoroacetophenone, revealing a dramatic increase in the chemoselectivity of the reaction when LiCl is introduced as an additive. This observation, combined with recent related breakthroughs in synthesis, points towards the existence of a trilateral Li/Mg/Zn synergistic effect.

  7. Magnesium and magnesium alloys

    SciTech Connect

    Avedesian, M.; Baker, H.

    1998-12-31

    This new handbook is the most comprehensive publication of engineering information on commercial magnesium alloys under one cover in the last sixty years. Prepared with the cooperation of the International Magnesium Association, it presents the industrial practices currently used throughout the world, as well as the properties of the products critical to their proper application. Contents include: general characteristics; physical metallurgy; melting, refining, alloying, recycling, and powder production; casting; heat treatment; forging, rolling, and extrusion; semisolid processing; forming; joining; cleaning and finishing; selection, application, and properties of grades and alloys; design considerations; mechanical behavior and wear resistance; fatigue and fracture-mechanics; high-temperature strength and creep; corrosion and stress-corrosion cracking; specification.

  8. Experimental study of the astrophysically important Na23(α,p)Mg26 and Na23(α,n)Al26 reactions

    DOE PAGES

    Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.; ...

    2016-12-19

    The 23Na(α,p) 26Mg and 23Na(α,n) 26Al reactions are important for our understanding of the 26Al abundance in massive stars. The aim of this work is to report on a direct and simultaneous measurement of these astrophysically important reactions using an active target system. The reactions were investigated in inverse kinematics using 4He as the active target gas in the detector. We measured the excitation functions in the energy range of about 2 to 6 MeV in the center of mass. We have found that the cross sections of the 23Na(α,p) 26Mg and the 23Na(α,n) 26Al reactions are in good agreementmore » with previous experiments and with statistical-model calculations. As a result, the astrophysical reaction rate of the 23Na(α,n) 26Al reaction has been reevaluated and it was found to be larger than the recommended rate.« less

  9. Analysis of longitudinal momentum distribution data of 26-29P isotopes in stripping reactions

    NASA Astrophysics Data System (ADS)

    Kumar, Ravinder; Singh, Pardeep; Kumar, Rajiv

    2017-02-01

    The orbital occupancy of the stripped proton in the phosphors isotopes with mass number 26-29 have been determined through the analysis of longitudinal momentum distributions (LMDs) of 25-28Si core fragments coming from 9Be(26-28P,25-27Si)X and 12C(29P,28Si)Y stripping reactions at high energies. It has been found that the probability of occupying d-orbital by the stripped proton is 40-60%, 30-50%, 30-50% and 0-20% in 26-29P isotopes, respectively. The effects of Coulomb barrier for the possibility of halo structure in proton-rich nuclei has also been examined and found that it decreases the chance of possessing halo structure in proton-rich nuclei.

  10. Experimental Plan of the 25Mg(p, γ)26Al Resonance Capture Reaction at Jinping Underground Laboratory

    NASA Astrophysics Data System (ADS)

    Li, Z. H.; Su, J.; Li, Y. J.; Guo, B.; Yan, S. Q.; Wang, Y. B.; Lian, G.; Zeng, S.; Zhang, Q. W.; He, G. Z.; Gan, L.; Zhou, C.; Liu, W. P.; Li, K. A.; Yu, X. Q.; Tang, X. D.; He, J. J.; Qian, Y. Z.

    The observation of 26Al is an useful tool for γ-ray astronomy and in studies of galactic chemical evolution. The most likely mechanism for 26A1 nucleosynthesis is in the hydrogen burning MgAl cycle, and the 26A1 production from the 25Mg(p, γ)26Al reaction at the important temperature range below T = 0.2 is still not well known. We present a proposal to measure the resonance strength of 58 keV resonance level of the 25Mg(p, γ)26Al reaction, and the effective counting rate is estimated for the direct measurement at Jinping underground laboratory.

  11. Magnesium in Prevention and Therapy.

    PubMed

    Gröber, Uwe; Schmidt, Joachim; Kisters, Klaus

    2015-09-23

    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).

  12. Neutron induced reactions on aluminum-26, chloride-36 and calcium-41 and their astrophysical implications

    NASA Astrophysics Data System (ADS)

    de Smet, Liesbeth Paula

    In this work (n,p) and (n,a) reactions on 26 A1, 36 Cl and 41 Ca are studied as a function of the neutron energy. The measurements were performed at the high resolution GELINA time-of-flight facility of the IRMM in Geel, Belgium. Besides the nuclear physics information obtained from the resonance analysis of the reaction cross sections, these reactions are of importance in the understanding of the observed 36 S and 26 Al solar abundances. In the case of 26 Al, the 26 A1(n,a) 23 Na cross section up to 45 keV has been determined. Six resonances are observed. For three of them, the total level width and the spin could be calculated. For most of the resonances the obtained resonance parameters are in agreement with previous data. The calculated Maxwellian Averaged Cross Section values (MACS) used in stellar model calculations confirm that 26 Al is indeed severely depleted by neutron captures in AGB stars. In the (n,p) and (n,a) measurements on 36 Cl, eighteen resonances are observed in the energy region up to 250 keV, whereas eight were identified before. Only the lowest energy resonance shows a significant (n,(x)-contribution of (76±7)%, which is in perfect agreement with the value reported before. Furthermore, for four resonances, the resonance strength, spin, total and partial width G p could be determined. They are in good agreement with previous data, but the achieved accuracy is better. The calculated MACS values are used in stellar model calculations to trace the origin of 36 S and reveal that the weak component of the s-process occurring in massive stars accounts for almost the entire production of solar 36 S. The 41 Ca(n,a) 3 8Ar measurement is the first ever reported in the resonance region and affects the 36 S abundance through 41 Ca(n,a) 38 Ar(n,g) 39 Ar(n,a) 36 S. Twelve resonances are observed in the energy region up to 45 keV. For most of them the area, the total width, the spin and a value for G n /G p could be determined. After extension of the energy

  13. /sup 26/Al(n,p)/sup 26/Mg reaction: Comparison between the Hauser-Feshbach formula and the exact random-matrix result for the cross section

    SciTech Connect

    Thomas, J.; Zirnbauer, M.R.; Langanke, K.

    1986-06-01

    We have calculated the /sup 26/Al(n,p)/sup 26/Mg reaction rate using an exact expression for the compound-nucleus cross section derived recently by Verbaarschot et al. This reaction is astrophysically important, and it happens to fall in a kinematic regime where the exact expression is expected to yield large deviations from the standard Hauser-Feshbach formula. We find that the exact statistical cross section is 20% lower at energies greater than 300 keV, and drops to 40% lower at 0 energy but still does not describe the available data. These deviations are quite similar to those predicted by the formula of Tepel et al.

  14. Magnesium and chromium isotope evidence for initial melting by radioactive decay of 26Al and late stage impact-melting of the ureilite parent body

    NASA Astrophysics Data System (ADS)

    van Kooten, Elishevah M. M. E.; Schiller, Martin; Bizzarro, Martin

    2017-07-01

    Polymict ureilites are meteoritic breccias that provide insights into the differentiation history of the ureilite parent body. We have sampled a total of 24 clasts from the polymict ureilite Dar al Gani 319, representing a variety of lithologies such as mantle residues, cumulates and crustal fragments that are genetically related to monomict ureilites. In addition, we sampled four non-indigenous dark clasts and two chondrule-containing clasts from the same meteorite. We report on the petrology and the bulk mass-dependent and mass-independent magnesium and chromium isotope systematics of these clasts. The DaG 319 polymict ureilite consists predominantly of clasts related to Main Group ureilite residues (MG clasts) with varying Mg#s (0.74-0.91), as well as a significant fraction of olivine-orthopyroxene clasts related to Hughes Type ureilites (HT clasts) with consistently high Mg#s (∼0.89). In addition, DaG 319 contains less abundant feldspathic clasts that are thought to represent melts derived from the ureilite mantle. A significant mass-dependent Mg-isotope fractionation totaling Δμ25 Mg = ∼450 ppm was found between isotopically light feldspathic clasts (μ25 Mg = -305 ± 25 to 15 ± 12 ppm), MG clasts (μ25 Mg = -23 ± 51 ppm) and HT clasts (μ25 Mg = 157 ± 21 ppm). We suggest that this isotopic offset is the result of equilibrium isotope fractionation during melting in the presence of an isotopically light magnesite component. We propose Mg-carbonates to be stable in the upper ureilite mantle, and pure carbon phases such as graphite to be stable at higher pressures. This is consistent with HT clasts lacking carbon-related phases, whereas MG clasts contain abundant carbon. The timing of differentiation events for the ureilitic clasts are constrained by high precision 53Mn-53Cr systematics and 26Al-26Mg model ages. We show that a dichotomy of ages exist between the differentiation of main group ureilite residues and HT cumulates rapidly after CAI formation

  15. Effect of magnesium on gastrointestinal transit time in normal and diabetic rats: possible mechanism of action.

    PubMed

    Adewoye, E O; Ige, A O

    2012-12-01

    Many gastrointestinal complications in diabetes are connected to neurohumoral dysfunction resulting in abnormalities of intestinal motility, secretion and absorption. Minerals have been reported as essential cofactors for basic cellular reactions but there is dearth of information on effect of Magnesium on gastrointestinal transit time (GITT) and the mechanism of action. Sixty male albino Wistar rats (180 - 200g) were grouped into twelve of five animals each. Group 1 (control) received 0.2ml saline. Groups 2-6 were normal rats treated with magnesium sulphate (as magnesium) (500mg/kg), adrenaline (0.5mg/kg), magnesium (500mg/kg) and adrenaline (0.5mg/kg), prazosin (1mg/kg) and both magnesium (500mg/kg) and prazosin (1mg/kg) respectively. Groups 7 - 12 were diabetic rats treated as in groups 1- 6. Diabetes was induced intraperitoneally with alloxan (120mg/kg bwt). There was significant (p<0.05) reduction in GITT index in normal rats treated with magnesium, prazosin and combination of magnesium and prazosin compared with control. Treatment with adrenaline alone produced significant increase in GITT. However treatment with both magnesium and adrenaline produced significant reduction compared with control. This reduction in GITT was similar to that obtained in magnesium only and prazosin only treated groups. Diabetic groups showed significant reduction in GITT in all treated groups except the adrenaline only treated group which produced significant increase in GITT. The significant reduction in GITT produced by magnesium in both normal and diabetic animals was comparable to that produced by prazosin (an á-adrenoceptor antagonist) indicating that magnesium may be inhibiting gastrointestinal smooth muscle contraction through á-adrenoceptor antagonist pathway.

  16. The 26gAl(p,g)27Si reaction in Novae

    NASA Astrophysics Data System (ADS)

    Ruiz, Chris; Parikh, A.; José, J.; Buchmann, L.; Caggiano, J. A.; Chen, A. A.; Clark, J. A.; Crawford, H.; Davids, B.; D'Auria, J. M.; Davis, C.; Deibel, C.; Erikson, L.; Fogarty, L.; Frekers, D.; Greife, U.; Hussein, A.; Hutcheon, D. A.; Huyse, M.; Jewett, C.; Laird, A. M.; Lewis, R.; Mumby-Croft, P.; Olin, A.; Ottewell, D. F.; Ouellet, C. V.; Parker, P.; Pearson, J.; Ruprecht, G.; Trinczek, M.; Vockenhuber, C.; Wrede, C.

    The 26gAl(p,γ)27Si Reaction in Novae PoS(NIC-IX)004 1 TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada 2 Wright Nuclear Structure Laboratory, Yale University, New Haven, Conneticut 06520-8124, USA 3 Dept. de Física í Enginyeria Nuclear, Universitat Politécnica de Catalunya, Barcelona, Spain 4 Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona, Spain 5 McMaster University, Hamilton, ON L8S 481, Canada 6 Simon Fraser University, Burnaby, BC V5A 1S6, Canada 7 Department of Physics, Colorado School of Mines, Golden, Colorado 80401, USA 8 National University of Ireland, Maynooth, Co. Kildare, Ireland 9 Institut für Kernphysik, Westfälische Willhelms-Universität Münster, 48149 Münster, Germany 10 University of Northern British Columbia, Prince George, BC V2N 4Z9, Canada 11 Katholieke Universiteit Leuven, 3000 Leuven, Belgium 12 Department of Physics, University of York, York YO10 5DD, United Kingdom The 184 keV resonance strength in the 26gAl(p,γ)27Si reaction was measured in inverse kinematics using the DRAGON facility at TRIUMF-ISAC. We obtain a value of ωγ=35±7 μeV for the strength and ER=184±1 keV for the resonance energy. These values are consistent with p-wave capture into the 7652(3) keV state in 27Si. We discuss the implications of these results for 26gAl nucleosynthesis in a typical O-Ne white dwarf nova.

  17. A study of the single neutron knockout reaction from silicon-26 and sulfur-30

    NASA Astrophysics Data System (ADS)

    Reynolds, Robert R., Jr.

    The use of single nucleon and two-like nucleon knockout reactions of medium to heavy mass exotic beams on light targets has proven an invaluable tool in exploring nuclear properties away from the valley of beta-stability up to the proton and neutron drip-lines. The nuclear shell model has had a great amount of success in describing structural properties of nucleons populating states from the 1s1p-shells up to the 2p1f-shells, of particular interest is the success of the USD shell model used in the truncated 2s1d-shell space. The USD Hamiltonian was updated in 2005 to include the effects of exotic nuclei. Using relativistic beam velocities greater then 30% of the speed of light allows for the direct exploration of underlying single particle valence state structure. Comparisons between current shell models and experimental results are showing discrepancies between measured and theoretical cross sections. The focus of the present work is on the single neutron knockout reactions 9Be(26Si,25Si+gamma) and 9 Be(30S,29S+gamma). Relativistic beams containing 26Si and 30S were created at the National Superconducting Cyclotron Laboratory's Coupled-Cyclotron Facility using the A1900 fragment separator. The secondary 376 mg/cm2 thick 9Be target was located at the pivot point of the S800, a large-acceptance, high-resolution spectrometer with a specialized detector system that allowed for accurate event-by-event particle identification of the incident and residual particles based on their mass and charge, as well as providing accurate longitudinal momentum distribution measurements of the post-target beam. The secondary target was also surrounded by SeGA, a gamma-ray detector array specifically designed for accurate Doppler reconstruction of observable gamma-rays into the emitting particles rest frame. Measurements were made of the direct inclusive and individual state population cross sections in the residual states, as well as the first measurements of electromagnetic

  18. Study of the Alm26(d,p)Al27 Reaction and the Influence of the Al26 0+ Isomer on the Destruction of Al26 in the Galaxy

    DOE PAGES

    Almaraz-Calderon, S.; Rehm, K. E.; Gerken, N.; ...

    2017-08-17

    The existence of 26Al (t1/2 = 7.17 × 105 yr) in the interstellar medium provides a direct confirmation of ongoing nucleosynthesis in the Galaxy. The presence of a low-lying 0+ isomer (26Alm), however, severely complicates the astrophysical calculations. Here we present for the first time a study of the 26Alm (d, p)27 Al reaction using an isomeric 26Al beam. The selectivity of this reaction allowed the study of ℓ = 0 transfers to T = 1/2, and T = 3/2 states in 27Al . Mirror symmetry arguments were then used to constrain the 26Al m (p,γ) 27Si reaction rate andmore » provide an experimentally determined upper limit of the rate for the destruction of isomeric 26Al via radiative proton capture reactions, which is expected to dominate the destruction path of 26Alm in asymptotic giant branch stars, classical novae, and core collapse supernovae.« less

  19. Study of the {sup 26}Al{sup/ital m}(d,p){sup 27}Al Reaction and the Influence of the {sup 26}Al 0{sup +) Isomer on the Destruction of {sup 26}Al in the Galaxy

    DOE PAGES

    Almaraz-Calderon, S.; Rehm, K. E.; Gerken, N.; ...

    2017-08-17

    The existence of Al-26 (t(1/2) = 7.17 x 10 (5) yr ) in the interstellar medium provides a direct confirmation of ongoing nucleosynthesis in the Galaxy. The presence of a low-lying 0(+) isomer (Al-26(m) ), however, severely complicates the astrophysical calculations. We present for the first time a study of the Al-26(m) (d , p )(27) Al reaction using an isomeric Al-26 beam. The selectivity of this reaction allowed the study of l = 0 transfers to T = (1/2) , and T = (3/2) states in Al-27 . Mirror symmetry arguments were then used to constrain the Al-26(m) (pmore » , gamma )(27) Si reaction rate and provide an experimentally determined upper limit of the rate for the destruction of isomeric Al-26 via radiative proton capture reactions, which is expected to dominate the destruction path of Al-26(m) in asymptotic giant branch stars, classical novae, and core collapse supernovae« less

  20. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2011-01-01

    Seawater and natural brines accounted for about 54 percent of U.S. magnesium compounds production in 2010. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash-Wendover 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 in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its operation mentioned above.

  1. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2010-01-01

    Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, 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 in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

  2. Magnesium substitution in brushite cements.

    PubMed

    Alkhraisat, Mohammad Hamdan; Cabrejos-Azama, Jatsue; Rodríguez, Carmen Rueda; Jerez, Luis Blanco; Cabarcos, Enrique López

    2013-01-01

    The use of magnesium-doped ceramics has been described to modify brushite cements and improve their biological behavior. However, few studies have analyzed the efficiency of this approach to induce magnesium substitution in brushite crystals. Mg-doped ceramics composed of Mg-substituted β-TCP, stanfieldite and/or farringtonite were reacted with primary monocalcium phosphate (MCP) in the presence of water. The cement setting reaction has resulted in the formation of brushite and newberyite within the cement matrix. Interestingly, the combination of SAED and EDX analyses of single crystal has indicated the occurrence of magnesium substitution within brushite crystals. Moreover, the effect of magnesium ions on the structure, and mechanical and setting properties of the new cements was characterized as well as the release of Ca(2+) and Mg(2+) ions. Further research would enhance the efficiency of the system to incorporate larger amounts of magnesium ions within brushite crystals.

  3. Magnesium in Prevention and Therapy

    PubMed Central

    Gröber, Uwe; Schmidt, Joachim; Kisters, Klaus

    2015-01-01

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

  4. Role of magnesium ions in the reaction mechanism at the interface between Tm1631 protein and its DNA ligand.

    PubMed

    Ogrizek, Mitja; Konc, Janez; Bren, Urban; Hodošček, Milan; Janežič, Dušanka

    2016-01-01

    A protein, Tm1631 from the hyperthermophilic organism Thermotoga maritima belongs to a domain of unknown function protein family. It was predicted that Tm1631 binds with the DNA and that the Tm1631-DNA complex is an endonuclease repair system with a DNA repair function (Konc et al. PLoS Comput Biol 9(11): e1003341, 2013). We observed that the severely bent, strained DNA binds to the protein for the entire 90 ns of classical molecular dynamics (MD) performed; we could observe no significant changes in the most distorted region of the DNA, where the cleavage of phosphodiester bond occurs. In this article, we modeled the reaction mechanism at the interface between Tm1631 and its proposed ligand, the DNA molecule, focusing on cleavage of the phosphodiester bond. After addition of two Mg(2+) ions to the reaction center and extension of classical MD by 50 ns (totaling 140 ns), the DNA ligand stayed bolted to the protein. Results from density functional theory quantum mechanics/molecular mechanics (QM/MM) calculations suggest that the reaction is analogous to known endonuclease mechanisms: an enzyme reaction mechanism with two Mg(2+) ions in the reaction center and a pentacovalent intermediate. The minimum energy pathway profile shows that the phosphodiester bond cleavage step of the reaction is kinetically controlled and not thermodynamically because of a lack of any energy barrier above the accuracy of the energy profile calculation. The role of ions is shown by comparing the results with the reaction mechanisms in the absence of the Mg(2+) ions where there is a significantly higher reaction barrier than in the presence of the Mg(2+) ions.Graphical abstractA protein, Tm1631 from the hyperthermophilic organism Thermotoga maritima belongs to a domain of unknown function protein family. We modeled the reaction mechanism at the interface between Tm1631 and its proposed ligand, the DNA molecule, focusing on cleavage of the phosphodiester bond.

  5. Investigation on the thermo-chemical reaction mechanism between yttria-stabilized zirconia (YSZ) and calcium-magnesium-alumino-silicate (CMAS)

    NASA Astrophysics Data System (ADS)

    Zhang, Dong-Bo; Wang, Bin-Yi; Cao, Jian; Song, Guan-Yu; Liu, Juan-Bo

    2015-03-01

    Thermal barrier coatings (TBCs) with Y2O3-stabilized ZrO2 (YSZ) top coat play a very important role in advanced turbine blades by considerably increasing the engine efficiency and improving the performance of highly loaded blades. However, at high temperatures, environment factors result in the failure of TBCs. The influence of calcium-magnesium-alumino-silicate (CMAS) is one of environment factors. Although thermo-physical effect is being paid attention to, the thermo-chemical reaction becomes the hot-spot in the research area of TBCs affected by CMAS. In this paper, traditional twolayered structured TBCs were prepared by electron beam physical vapor deposition (EBPVD) as the object of study. TBCs coated with CMAS were heated at 1240°C for 3 h. Additionally, 15 wt.% simulated molten CMAS powder and YSZ powder were mixed and heated at 1240°C or 1350°C for 48 h. SEM and EDS were adopted to detect morphology and elements distribution. According to XRD and TEM results, it was revealed that CMAS react with YSZ at high temperature and form ZrSiO4, Ca0.2Zr0.8O1.8 and Ca0.15Zr0.85O1.85 after reaction, as a result, leading to the failure of TBCs and decreasing the TBC lifetime.

  6. Magnesium Test

    MedlinePlus

    ... Mag Formal name: Magnesium Related tests: Calcium , Potassium , Phosphorus , PTH , Vitamin D At a Glance Test Sample ... checked to help diagnose problems with calcium, potassium, phosphorus , and/or parathyroid hormone – another component of calcium ...

  7. Magnesium fluoride recovery method

    SciTech Connect

    Gay, R.L.; McKenzie, D.E.

    1989-10-17

    This patent describes a method of obtaining magnesium fluoride substantially free from radioactive uranium from a slag formed in the production of metallic uranium by the reduction of depleted uranium tetrafluoride with metallic magnesium in a retort wherein the slag contains the free metals magnesium and uranium and also oxides and fluorides of the metals, the slag having a radioactivity level of at least about 7,000 pCi/gm. The method comprises: grinding the slag to a median particle size of about 200 microns; contacting the ground slag in a reaction zone with an acid having a strength of from about 0.5 to 1.5 N for a time of from about 4 to about 20 hours in the presence of a catalytic amount of iron, the reaction zone being maintained at a temperature within the range of from about 60{degrees} to 90{degrees} C. and the weight of ratio of slag to acid being within the range of from about 1:2 to 1:6 to produce a liquid product and a particulate solid product; removing the liquid product; treating the particulate solid product; and repeating steps at least one more time 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.

  8. Structural and magnetic properties of magnesium ferrite nanoparticles prepared via EDTA-based sol-gel reaction

    NASA Astrophysics Data System (ADS)

    Hussein, Shaban I.; Elkady, Ashraf S.; Rashad, M. M.; Mostafa, A. G.; Megahid, R. M.

    2015-04-01

    Magnesium ferrite (MgFe2O4) nanoparticles have been prepared, for the first time, by ethylene diamine tetraacetic acid (EDTA)-based sol-gel combustion method. The prepared ferrite system is calcined at 400, 500 and 600 °C. Thermo-gravimetric and differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometry (VSM) were applied for elucidating the structural and magnetic properties of the prepared system. XRD patterns revealed that the prepared system have two spinel MgFe2O4 structures, namely cubic and tetragonal phases that are dependent on calcination temperature (Tc). The crystallite sizes varied from 8.933 to 41.583 nm, and from 1.379 to 292.565 nm for the cubic and tetragonal phases respectively depending on Tc. The deduced lattice parameters for the cubic and (tetragonal) systems are a=8.368, 8.365 and 8.377 and (a=7.011, 5.922, 5.908 and c=6.622, 8.456, 8.364) Å at Tc=400, 500 and 600 °C respectively. While the cation distribution of the cubic phase is found to be mixed spinel and Tc-dependent, it is an inverse spinel in the tetragonal phase where the Fe3+ ions occupy both the tetrahedral A- and octahedral B-sites in almost equal amount; the Mg2+ ions are found to occupy only the B-sites. The HRTEM and selected-area electron diffraction (SAED) revealed the detailed morphology of the nanoparticles, and confirmed their crystalline spinel structure. VSM indicated the existence of an appreciable fraction of superparamagnetic particles at room temperature, with pure superparamagnetic behavior observed for samples calcined at 400 °C. Besides, the magnetic properties are found to change by thermal treatment as a result of the varied phase concentration, cation distribution and lattice parameters. Thus, the new synthesis route used in this study by applying EDTA as an organic precursor for preparing MgFe2O4 nanoparticles at

  9. Carbothermal Production of Magnesium in Vacuum

    NASA Astrophysics Data System (ADS)

    Qu, Tao; Yang, Bin; Tian, Yang; Dai, Yongnian

    Carbothermal production has been recognized as conceptually the cleanest and energy-efficient route to magnesium metal, but has suffered from technical challenges of development and scale-up. Work by National Engineering Laboratory for Vacuum Metallurgy of China has overcome some barriers of carbothermal production. By changing the condition of condensation, the magnesium vapor is condensed into bulk, so that the risk of magnesium powder explosion can be avoided, and it can reduce the oxygen content, enhance the recovered of magnesium. The mechanism of the carbothermic reduction process has be investigated, the reversion reactions are favored below 1373K at 30 100Pa, and reversion below 9% at bulk in condensation. Purification of magnesium by distillation is known technology, but difficulties with continuous operation are also known. In terms of process control, distillation temperature and pressure are controlled, the magnesium vapor is condensed into liquid, and then solidified into a solid, the solid magnesium is purified (>99.9%).

  10. High-precision {sup 28}Si(p,t){sup 26}Si reaction to determine {sup 22}Mg({alpha},p){sup 25}Al reaction rates

    SciTech Connect

    Matic, A.; Berg, A. M. van den; Harakeh, M. N.; Woertche, H. J.; Beard, M.; Berg, G. P. A.; Goerres, J.; LeBlanc, P.; O'Brien, S.; Wiescher, M.; Fujita, K.; Hatanaka, K.; Sakemi, Y.; Shimizu, Y.; Tameshige, Y.; Tamii, A.; Yosoi, M.; Adachi, T.; Fujita, Y.; Shimbara, Y.

    2011-08-15

    The rise time of stellar x-ray bursts is a signature of thermonuclear runaway processes in the atmosphere of neutron stars and is highly sensitive to a series of ({alpha},p) reactions via high-lying resonances in sd-shell nuclei. Lacking data for the relevant resonance levels, the stellar reaction rates have been calculated using statistical, Hauser-Feshbach models, assuming a high-level density. This assumption may not be correct in view of the selectivity of the ({alpha},p) reaction to natural parity states. We measured the {sup 28}Si(p,t){sup 26}Si reaction with a high-resolution spectrometer to identify resonance levels in {sup 26}Si above the {alpha}-emission threshold at 9.164 MeV excitation energy. These resonance levels are used to calculate the stellar reaction rate of the {sup 22}Mg({alpha},p){sup 25}Al reaction and to test the validity of the statistical assumption.

  11. Production of magnesium metal

    DOEpatents

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

    2012-04-10

    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 also relates to the magnesium metal produced by the processes described herein.

  12. Magnesium compounds

    USGS Publications Warehouse

    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.

  13. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2002-01-01

    Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  14. Magnesium fluoride recovery method

    SciTech Connect

    Gay, R.L.; McKenzie, D.E.

    1989-10-17

    A method of obtaining magnesium fluoride substantially free from radioactive uranium from a slag formed in the production of metallic uranium by the reduction of depleted uranium tetrafluoride with metallic magnesium in a retort wherein the slag contains the free metals magnesium and uranium and also oxides and fluorides of the metals. The slag having a radioactivity level of at least about 7,000 rhoCi/gm. The method comprises the steps of: grinding the slag to a median particle size of about 200 microns; contacting the ground slag in a reaction zone with an acid having a strength of from about 0.5 to 1.5 N for a time of from about 4 to about 20 hours in the presence of a catalytic amount of iron; removing the liquid product; treating the particulate solid product; repeating the last two steps at least one more time 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 rhoCi/gm.

  15. Solvent Influences on the Molecular Aggregation of Magnesium Aryloxides

    SciTech Connect

    ZECHMANN,CECILIA A.; BOYLE,TIMOTHY J.; RODRIGUEZ,MARK A.; KEMP,RICHARD A.

    2000-07-14

    Magnesium aryloxides were prepared in a variety of solvents through the reaction of dibutyl magnesium with sterically varied aryl alcohols: 2,6-dimethylphenol (H-DMP), 2,6-diisopropylphenol (H-DIP), and 2,4,6-trichlorophenol (H-TCP). Upon using a sufficiently strong Lewis-basic solvent, the monomeric species Mg(DMP){sub 2}(py){sub 3} (1, py = pyridine), Mg(DIP){sub 2}(THF){sub 3}, (2a, THF = tetrahydrofuran) Mg(TCP){sub 2}(THF){sub 3} (3) were isolated. Each of these complexes possesses a five-coordinate magnesium that adopts a trigonal bipyramidal geometry. In the absence of a Lewis base, the reaction with H-DIP yields a soluble trinuclear complex, [Mg(DIP){sub 2}]{sub 3} (2b). The Mg metal centers in 2b adopt a linear arrangement with a four-coordinate central metal while the outer metal centers are reduced to just three-coordinate. Solution spectroscopic methods suggest that while 2b remains intact, the monomeric species (1, 2a, and 3) are involved in equilibria, which facilitate intermolecular ligand transfer.

  16. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

  17. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2004-01-01

    Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida; from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties, and Rohm & Haas; and from magnesite in Nevada by Premier Chemicals. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  18. Reactions Involving Calcium and Magnesium Sulfates as Potential Sources of Sulfur Dioxide During MSL SAM Evolved Gas Analyses

    NASA Technical Reports Server (NTRS)

    McAdam, A. C.; Knudson, C. A.; Sutter, B.; Franz, H. B.; Archer, P. D., Jr.; Eigenbrode, J. L.; Ming, D. W.; Morris, R. V.; Hurowitz, J. A.; Mahaffy, P. R.; hide

    2016-01-01

    The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) have analyzed several subsamples of <150 micron fines from ten sites at Gale Crater. Three were in Yellowknife Bay: the Rocknest aeolian bedform (RN) and drilled Sheepbed mudstone from sites John Klein (JK) and Cumberland (CB). One was drilled from the Windjana (WJ) site on a sandstone of the Kimberly formation. Four were drilled from sites Confidence Hills (CH), Mojave (MJ), Telegraph Peak (TP) and Buckskin (BK) of the Murray Formation at the base of Mt. Sharp. Two were drilled from sandstones of the Stimson formation targeting relatively unaltered (Big Sky, BY) and then altered (Greenhorn, GH) material associated with a light colored fracture zone. CheMin analyses provided quantitative sample mineralogy. SAM's evolved gas analysis mass spectrometry (EGA-MS) detected H2O, CO2, O2, H2, SO2, H2S, HCl, NO, and other trace gases. This contribution will focus on evolved SO2. All samples evolved SO2 above 500 C. The shapes of the SO2 evolution traces with temperature vary between samples but most have at least two "peaks' within the wide high temperature evolution, from approx. 500-700 and approx. 700-860 C (Fig. 1). In many cases, the only sulfur minerals detected with CheMin were Ca sulfates (e.g., RN and GH), which should thermally decompose at temperatures above those obtainable by SAM (>860 C). Sulfides or Fe sulfates were detected by CheMin (e.g., CB, MJ, BK) and could contribute to the high temperature SO2 evolution, but in most cases they are not present in enough abundance to account for all of the SO2. This additional SO2 could be largely associated with x-ray amorphous material, which comprises a significant portion of all samples. It can also be attributed to trace S phases present below the CheMin detection limit, or to reactions which lower the temperatures of SO2 evolution from sulfates that are typically expected to thermally decompose

  19. Porous magnesium carboxylate framework: synthesis, X-ray crystal structure, gas adsorption property and heterogeneous catalytic aldol condensation reaction.

    PubMed

    Saha, Debraj; Sen, Rupam; Maity, Tanmoy; Koner, Subratanath

    2012-06-28

    A new three-dimensional alkaline-earth metal-organic framework (MOF) compound, [Mg(Pdc)(H(2)O)](n) (1) (H(2)Pdc = pyridine-2,5-dicarboxylic acid), has been synthesized and structurally characterized by single crystal X-ray diffraction analysis. Compound 1 features a 3D porous framework afforded by the Mg(2)-diad centers through formation of interconnected chair like structural motifs. A nitrogen adsorption study confirms the microporosity of compound 1 with a BET surface area of 211 ± 12 m(2) g(-1). Upon dehydration, the BET surface area of 1 is enhanced to a value of 463 ± 36 m(2) g(-1) due to removal of coordinated water molecule. After rehydration, the compound reverts to its original form as evidenced by powder X-ray diffraction and IR spectroscopic analysis and N(2) sorption measurement. Compound 1 retains its pore structure with a variable BET surface area in several cycles of dehydration and rehydration processes indicating robustness of the framework in [Mg(Pdc)(H(2)O)](n) (1). Compound 1 catalyzes the aldol condensation reactions of various aromatic aldehydes with acetone and cyclohexanone in heterogeneous conditions. Notably, the catalytic activity of the compound is enhanced upon dehydration. The catalyst can be recycled and reused several times without significant loss of activity.

  20. Heterogeneous-phase reactions of nitrogen dioxide with vermiculite-supported magnesium oxide (as applied to the control of jet engine test cell emissions). Doctoral thesis

    SciTech Connect

    Kimm, L.T.

    1995-11-01

    Controlling nitrogen oxides (NOx) from a non-steady-state stationary source like a jet engine test cell (JETC) requires a method that is effective over a wide range of conditions. A heterogeneous, porous, high surface area sorbent material comprised of magnesium oxide powder attached to a vermiculite substrate has been commercially developed for this purpose. Data from extensive laboratory testing of this material in a packed-bed flow system are presented. NO2 removal efficiencies, kinetics, and proposed NO2 removal mechanisms over a range of representative JETC exhaust gas characteristics are described. Exhaust gas variables evaluated included: NO2 concentration, temperature, flow rate (retention time), oxygen content, and moisture content. Availability of water and oxygen were found to be important variables. It is probable that water is necessary for the conversion of MgO to Mg(OH)2, which is a more reactive compound having thermal stability over the range of temperatures evaluated. Gaseous oxygen serves to oxidize NO to NO2, the latter being more readily removed from the gas stream. The presence of oxygen also serves to offset thermal decomposition of NO2 or surface nitrite/nitrate. Effective `lifetime` and regenerability of the exposed sorbent material were also evaluated. NO2 removal efficiencies were found to greatly exceed those for NO, with a maximum value greater than 90 percent. The effective conversion of NO to NO2 is a crucial requirement for removal of the former. The reaction between NO2 and MgO-vermiculite is first-order with respect to NO2.

  1. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2003-01-01

    Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

  2. Magnesium compounds

    USGS Publications Warehouse

    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.

  3. Low magnesium level

    MedlinePlus

    Low magnesium level is a condition in which the amount of magnesium in the blood is lower than normal. The medical ... that convert or use energy ( metabolism ). When the level of magnesium in the body drops below normal, ...

  4. Cement from magnesium substituted hydroxyapatite.

    PubMed

    Lilley, K J; Gbureck, U; Knowles, J C; Farrar, D F; Barralet, J E

    2005-05-01

    Brushite cement may be used as a bone graft material and is more soluble than apatite in physiological conditions. Consequently it is considerably more resorbable in vivo than apatite forming cements. Brushite cement formation has previously been reported by our group following the mixture of nanocrystalline hydroxyapatite and phosphoric acid. In this study, brushite cement was formed from the reaction of nanocrystalline magnesium-substituted hydroxyapatite with phosphoric acid in an attempt to produce a magnesium substituted brushite cement. The presence of magnesium was shown to have a strong effect on cement composition and strength. Additionally the presence of magnesium in brushite cement was found to reduce the extent of brushite hydrolysis resulting in the formation of HA. By incorporating magnesium ions in the apatite reactant structure the concentration of magnesium ions in the liquid phase of the cement was controlled by the dissolution rate of the apatite. This approach may be used to supply other ions to cement systems during setting as a means to manipulate the clinical performance and characteristics of brushite cements.

  5. Laser-induced magnesium production from magnesium oxide using reducing agents

    NASA Astrophysics Data System (ADS)

    Mohamed, M. S.; Yabe, T.; Baasandash, C.; Sato, Y.; Mori, Y.; Shi-Hua, Liao; Sato, H.; Uchida, S.

    2008-12-01

    Experiments for laser induced production of magnesium (Mg) from magnesium oxide (MgO) using reducing agents (R) were conducted. In these experiments, continuous wave CO2 focused laser is focused on a mixture of magnesium oxide and reducing agent. High power density of focused laser leads to high temperature and the reduction reaction resulting in Mg production. The resultant vapor is collected on a copper plate and analyzed in terms of magnesium deposition efficiency. Deposition efficiencies with various reducing agents such as Zr, C, and Si have been measured to be 60, 9.2, and 12.1 mg/kJ respectively. An excess addition of reducing agent over their corresponding reaction stoichiometric amounts is found to be optimum condition for the most of performed laser induced reactions. In addition, utilizing solar-pumped laser in Mg production with reducing agent will reduce CO2 emission and produce magnesium with high-energy efficiency and large throughput.

  6. Kinetic studies of Micrococcus luteus B-P 26 undecaprenyl diphosphate synthase reaction using 3-desmethyl allylic substrate analogs.

    PubMed

    Fujikura, Keitaro; Maki, Yuji; Ohya, Norimasa; Satoh, Mikiya; Koyama, Tanetoshi

    2008-03-01

    In order to investigate the substrate binding feature of undecaprenyl diphosphate synthase from Micrococcus luteus B-P 26 with respect to farnesyl diphosphate and a reaction intermediate, (Z,E,E)-geranylgeranyl diphosphate, we examined the reactivity of artificial substrate analogs, 3-desmethyl farnesyl diphosphate and 3-desmethyl Z-geranylgeranyl diphosphate, which lack the methyl group at the 3-position of farnesyl diphosphate and Z-geranylgeranyl diphosphate, respectively. Undecaprenyl diphosphate synthase did not accept either of the 3-desmethyl analogs as the allylic substrate, indicating that the methyl group at the 3-position of the allylic substrate is important in the undecaprenyl diphosphate synthase reaction. These analogs showed different inhibition patterns in the cis-prenyl chain elongation reaction with respect to the reactions of farnesyl diphosphate and Z-geranylgeranyl diphosphate as allylic substrate. These results suggest that the binding site for the natural substrate farnesyl diphosphate and those for the intermediate allylic diphosphate, which contains the cis-prenyl unit, are different during the cis-prenyl chain elongation reaction.

  7. Formation, solvolysis, and transcarbamoylation reactions of bis(S-glutathionyl) adducts of 2,4- and 2,6-diisocyanatotoluene.

    PubMed

    Day, B W; Jin, R; Basalyga, D M; Kramarik, J A; Karol, M H

    1997-04-01

    During our ongoing studies of the reactions of toluene diisocyanate (2,4- and 2,6-diisocyanatotoluene, TDI) in vivo, it became apparent that reactive form(s) of these diisocyanates reach(es) the circulatory system after passage through the respiratory system. Based on recent work by others regarding the transcarbamoylation reactions of monoisocyanates, we hypothesized that the reactive form could be masked as an S-thiocarbamoylglutathione adduct of one or more of the isocyanato moieties. In this study, the glutathione adducts of 2,4- and 2,6-diisocyanatotoluene were synthesized under physiological conditions. Bis adducts were the major products when near-equimolar amounts of glutathione and the individual diisocyanato compounds were mixed at physiological pH, and were formed in high yield. Little to no mono adducts formed under these reaction conditions. The masses of the bis adducts were confirmed by electrospray mass spectrometry (MS), and 1H NMR analysis strongly suggested that the thiol of the cysteine residue of glutathione was the nucleophile in each case. The rates of solvolysis of the two bis adducts in aqueous buffer under conditions of physiological temperature and pH were determined, and electrospray MS analysis showed that the corresponding mono(glutathionyl)-TDIs were formed in these reactions. Incubation in vitro of each of the bis(glutathionyl)-TDI adducts with a 12 amino acid peptide (Thr-Cys-Val-Glu-Trp-Leu-Arg-Arg-Tyr-Leu-Lys-Asn) at pH 7.5 resulted in transfer of one mono(glutathionyl)-toluylisocyanato moiety to the peptide as detected by HPLC and on-line electrospray MS analyses. In both the solvolysis and transfer experiments, the 2,4-TDI-derived bis(glutathionyl) adduct reacted most quickly, while both the bis(glutathionyl)-2,6-TDI adduct and its transfer product with the peptide were more stable than their 2,4-TDI-derived counterparts. The results indicate high stoichiometry in formation and ready transfer to nucleophilic sites of protein

  8. Angle-integrated measurements of the 26Al (d, n)27Si reaction cross section: a probe of spectroscopic factors and astrophysical resonance strengths

    NASA Astrophysics Data System (ADS)

    Kankainen, A.; Woods, P. J.; Nunes, F.; Langer, C.; Schatz, H.; Bader, V.; Baugher, T.; Bazin, D.; Brown, B. A.; Browne, J.; Doherty, D. T.; Estrade, A.; Gade, A.; Kontos, A.; Lotay, G.; Meisel, Z.; Montes, F.; Noji, S.; Perdikakis, G.; Pereira, J.; Recchia, F.; Redpath, T.; Stroberg, R.; Scott, M.; Seweryniak, D.; Stevens, J.; Weisshaar, D.; Wimmer, K.; Zegers, R.

    2016-01-01

    Measurements of angle-integrated cross sections to discrete states in 27Si have been performed studying the 26Al ( d, n) reaction in inverse kinematics by tagging states by their characteristic γ -decays using the GRETINA array. Transfer reaction theory has been applied to derive spectroscopic factors for strong single-particle states below the proton threshold, and astrophysical resonances in the 26Al ( p, γ) 27Si reaction. Comparisons are made between predictions of the shell model and known characteristics of the resonances. Overall very good agreement is obtained, indicating this method can be used to make estimates of resonance strengths for key reactions currently largely unconstrained by experiment.

  9. IWTS metal-water reaction rate evaluation (Fauske and Associates report 99-26)

    SciTech Connect

    DUNCAN, D.R.

    1999-07-29

    The report presents a thermal stability analysis of partially metallic particulate in two IWTS components, the knock out pot and settlers. Particulate in the knock out pot is thermally stable for combinations of average particle size and metal mass fraction which appear realistic. Particulate in the settlers is thermally stable when a realistic account of particle reactions over time, metal fraction, and size distribution is considered.

  10. Magnesium doping of boron nitride nanotubes

    DOEpatents

    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.

  11. Structure of Resonances in the Gamow Burning Window for the {sup 25}Al({rho},{gamma}){sup 26}Si Reaction in Novae

    SciTech Connect

    Doherty, D. T.; Woods, P. J.; Seweryniak, D.; Albers, M.; Ayangeakaa, A. D.; Carpenter, M. P.; Chiara, C. J.; David, H. M.; Harker, J. L.; Janssens, R. V. F.; Kankainen, A.; Lederer, C.; Zhu, S.

    2015-09-17

    A -ray spectroscopy study of excited states in 26Si has been performed using the 24Mg(3He,n) reaction at a beam energy of 10 MeV. In particular, states have been studied above the proton threshold relevant for burning in the 25Al(p, )26Si reaction in novae. This reaction in uences the amount of 26Al injected into the interstellar medium by novae, which contributes to the overall ux of cosmic gamma-ray emission from 26Al observed in satellite missions. The present results point strongly to the existence of a 0+ state at an excitation energy of 5890 keV lying within the Gamow burning window, which raises questions about the existence and properties of another, higher-lying state/resonance reported in previous experimental work. The existence of two such states within this excitation energy region cannot be understood in the framework of sd shell-model calculations.

  12. Absolute Determination for the Sodium-22(p,gamma)Magnesium-23 Reaction Rate: Consequences for Nucleosynthesis of Sodium-22 in Novae

    NASA Astrophysics Data System (ADS)

    Sallaska, Anne L.

    2010-11-01

    Hydrodynamic simulations of classical novae on ONe white dwarfs predict substantial production of 22Na. Observation of 22Na decay should be correlated with the corresponding nova because the half life of 22Na is only 2.6 years. The 1275-keV gamma ray from the beta decay of 22Na is, therefore, an excellent diagnostic for the nova phenomenon and a long-sought target of gamma-ray telescopes. Nova simulations determine the maximum 22Na-detection distance to be < 1 kpc for the INTEGRAL spectrometer SPI, consistent with its non-observation to date. However, model estimates are strongly dependent on the thermonuclear rate of the 22Na(p, gamma)23Mg reaction, which is the main destruction mechanism of 22Na in novae. The 22Na(p,gamma)23Mg rate is expected to be dominated by narrow, isolated resonances with Ep < 300 key. The currently employed rate is based on a single set of absolute resonance-strength measurements with Ep ≥ 290 keV, and one relative measurement of resonances with Ep ≥ 214 keV. Recently, a new level has been found in 23Mg which would correspond to a resonance at Ep = 198 keV that might dominate the reaction rate at nova temperatures. We have measured the 22Na(p, gamma) 23Mg resonance strengths directly and absolutely, in addition to resonance energies and branches. Proton beams were produced at the University of Washington and delivered to a specially designed beam line that included rastering and cold vacuum protection of the 22Na-implanted targets (fabricated at TRIUMF-ISAC). Two high-purity germanium detectors were employed and surrounded by anticoincidence shields to reduce cosmic backgrounds. Measurements were made on known 22Na+p resonances, which we observed at laboratory energies Ep = 213, 288, 454, 610 keV and on proposed resonances at Ep = 198, 209, and 232 key. The proposed resonances were not observed, and the upper limit placed on the 198-keV resonance strength indicates that the resonance at Ep = 213 keV still dominates the reaction rate

  13. Early irradiation of matter in the solar system - Magnesium /proton, neutron/ scheme

    NASA Technical Reports Server (NTRS)

    Heymann, D.; Dziczkaniec, M.

    1976-01-01

    The occurrence of positive and negative Mg-26 anomalies in inclusions of the Allende meteorite is explained in terms of proton bombardment of a gas of solar composition. A significant fraction of Mg-26 in the irradiated gas is stored temporarily in the form of radioactive Al-26 by the reaction Mg-26(p, n)Al-26. Proton fluxes of 10 to the 17th power to 10 to the 19th power protons per square centimeter per year at 1 million electron volts are inferred. Aluminum-rich materials condensing from the gas phase have positive Mg-26 anomalies, whereas magnesium-rich materials have negative Mg-26 anomalies. The proton flux required to account for the observed magnesium anomalies is used to investigate possible isotopic anomalies in the elements from oxygen to argon. Detectable isotopic anomalies are predicted only for neon. The anomalous neon is virtually pure Ne-22 from Na-22 decay. The predicted amount of anomalous Ne-22 is about 10 to the -8th power cubic centimeter (at standard temperature and pressure) per milligram of sodium.

  14. Choline Magnesium Trisalicylate

    MedlinePlus

    Choline magnesium trisalicylate is used to relieve the pain, tenderness, inflammation (swelling), and stiffness caused by arthritis ... painful shoulder. It is also used to relieve pain and lower fever. Choline magnesium trisalicylate is in ...

  15. Measurement of serum ionized magnesium in CAPD patients.

    PubMed

    Saha, H H; Harmoinen, A P; Pasternack, A I

    1997-01-01

    To evaluate the magnesium status of continuous ambulatory peritoneal dialysis (CAPD) patients using a new method for assessing the level of the ionized fraction of serum magnesium. Serum ionized magnesium was measured in CAPD patients using the ion-selective electrode for Mg2+. The Dialysis Unit of Tampere University Hospital. Twenty-six patients on CAPD (age: 21-81 years, mean 54 +/- 16 years; duration of CAPD: 3-52 months, mean 13 months), and 26 sex- and age-matched healthy controls. Both serum ionized magnesium (0.73 +/- 0.11 mmol/L vs 0.56 +/- 0.07 mmol/L, p < 0.001) and total magnesium (1.11 +/- 0.22 vs 0.81 +/- 0.08 mmol/L, p < 0.01) were higher in CAPD patients than in sex- and age-matched controls. The ionized magnesium fraction of total magnesium was slightly lower in dialysis patients in spite of the fact that 16/26 patients had serum albumin less than 36 g/L. Hypermagnesemia (mean serum ionized magnesium 0.78 +/- 0.10 mmol/L) was observed in the 13 of 26 patients with 0.75 mmol/L Mg2+ dialysate; those with lower magnesium dialysate (Mg2+ 0.50 mmol/L in 10/26 and Mg2+ 0.25 mmol/L in 3/26) had mean serum ionized magnesium at the upper normal margin (0.69 +/- 0.10 mmol/L). In CAPD patients with Mg2+ 0.5-0.75 mmol/L in their dialysis fluid, both serum ionized and total magnesium concentrations were higher but the ionized/total magnesium ratio was lower than in healthy control subjects. Use of ion-selective electrodes to measure ionized magnesium may be a more useful methodology than measuring total magnesium in the evaluation of magnesium status of CAPD patients, because it is not influenced by hypoalbuminemia or increased complexed fraction of magnesium often present in dialysis patients.

  16. Multi-elements (aluminium, copper, magnesium, manganese, selenium and zinc) determination in serum by dynamic reaction cell-inductively coupled plasma-mass spectrometry.

    PubMed

    Wah Fong, Bonnie Mei; Siu, Tak Shing; Kit Lee, Joseph Sai; Tam, Sidney

    2009-01-01

    Trace element determination in laboratory medicine is widely carried out by atomic absorption or emission spectroscopy. In the last decade, there has been a rapid growth in the use of inductively coupled plasma-mass spectrometry because of its strong detection power, and the possibility of multi-elements analysis in a single run. Having the advantages of smaller sample volume and better detection limit, we developed a method for the simultaneous determinations of six trace elements by using 100 microL serum, and the assay can be accomplished within 3 min. The method developed gave recovery of the six elements ranging from 97% to 117%. The method covered a wide dynamic range with manganese in the range of nmol/L, while magnesium was in the range of mmol/L. The detection limits were 0.001 mmol/L, 0.05 micromol/L, 2.0 nmol/L, 0.2 micromol/L, 0.05 micromol/L, and 0.01 micromol/L for magnesium, aluminium, manganese, copper, zinc, and selenium, respectively. All the six elements had intra-assay imprecision of less than 5%, and inter-assay imprecision of less than 8%. This fast and robust method is suitable for use in the clinical laboratory where short turnaround time is needed for managing patients with trace element deficiency or toxicity.

  17. Magnesium and Space Flight.

    PubMed

    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.

  18. Magnesium and Space Flight

    PubMed Central

    Smith, Scott M.; Zwart, Sara R.

    2015-01-01

    Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in 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. PMID:26670248

  19. B-side electron transfer promoted by absorbance of multiple photons in Rhodobacter sphaeroides R-26 reaction centers

    SciTech Connect

    Lin, S.; Jackson, J.A.; Taguchi, A.K.W.; Woodbury, N.W.

    1999-06-03

    Femtosecond transient absorbance spectra of quinone-depleted Rhodobacter sphaeroides R-26 reaction centers in the Q{sub X} transition region have been measured at 15 K under various excitation conditions. This study focuses on the excitation wavelength dependence and excitation intensity dependence of the formation of charge-separated states on the A- and B-side of the reaction center, judging from the bleaching of the 533 nm (B-side) and 544 nm (A-side) ground-state transitions of the reaction center bacteriopheophytins (H{sub A} and H{sub B}). Upon low-intensity selective excitation directly into the bacteriopheophytin Q{sub Y} transitions (near 760 nm), bleaching of both ground-state bacteriopheophytin Q{sub X} transitions appeared immediately, showing that initially either the A- or B-side bacteriopheophytin could be excited. However, both excited states ultimately resulted in P{sup +}H{sub A}{sup {minus}} formation under these conditions. Low-intensity excitation at any of the various wavelengths showed no difference in the kinetics of the A-side charge separation forming P{sup +}H{sub A}{sup {minus}} and no substantial formation of the B-side charge-separated state, P{sup +}H{sub B}{sup {minus}}. In contrast, high-intensity 595 nm excitation resulted in substantial long-lived bleaching of the B-side bacteriopheophytin ground-state transition at 533 nm. This 533 nm bleaching was formed with essentially the same time constant as the bleaching at 544 nm due to A-side charge separation. Both bleaching bands persisted at the longest times measured in quinone-removed reaction centers. The long-lived bleaching at 533 nm using high-intensity excitation most likely represents the formation of P{sup +}H{sub B}{sup {minus}} with a relative yield of nearly 40%. One possible mechanism for B-side electron transfer is that two-photon excitation of the reaction center resulting in the state P{sup *}B{sub B}{sup *} makes P{sup +}B{sub B}{sup {minus}} thermodynamically

  20. Monitoring Biodegradation of Magnesium Implants with Sensors

    NASA Astrophysics Data System (ADS)

    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.

  1. Reaction of bone nanostructure to a biodegrading Magnesium WZ21 implant - A scanning small-angle X-ray scattering time study.

    PubMed

    Grünewald, T A; Ogier, A; Akbarzadeh, J; Meischel, M; Peterlik, H; Stanzl-Tschegg, S; Löffler, J F; Weinberg, A M; Lichtenegger, H C

    2016-02-01

    Understanding the implant-bone interaction is of prime interest for the development of novel biodegrading implants. Magnesium is a very promising material in the class of biodegrading metallic implants, owing to its mechanical properties and excellent immunologic response during healing. However, the influence of degrading Mg implants on the bone nanostructure is still an open question of crucial importance for the design of novel Mg implant alloys. This study investigates the changes in the nanostructure of bone following the application of a degrading WZ21 Mg implant (2wt% Y, 1wt% Zn, 0.25wt% Ca and 0.15wt% Mn) in a murine model system over the course of 15months by small angle X-ray scattering. Our investigations showed a direct response of the bone nanostructure after as little as 1month with a realignment of nano-sized bone mineral platelets along the bone-implant interface. The growth of new bone tissue after implant resorption is characterized by zones of lower mineral platelet thickness and slightly decreased order in the stacking of the platelets. The preferential orientation of the mineral platelets strongly deviates from the normal orientation along the shaft and still roughly follows the implant direction after 15months. We explain our findings by considering geometrical, mechanical and chemical factors during the process of implant resorption. The advancement of surgical techniques and the increased life expectancy have caused a growing demand for improved bone implants. Ideally, they should be bio-resorbable, support bone as long as necessary and then be replaced by healthy bone tissue. Magnesium is a promising candidate for this purpose. Various studies have demonstrated its excellent mechanical performance, degradation behaviour and immunologic properties. The structural response of bone, however, is not well known. On the nanometer scale, the arrangement of collagen fibers and calcium mineral platelets is an important indicator of structural

  2. Biodegradable magnesium-based screw clinically equivalent to titanium screw in hallux valgus surgery: short term results of the first prospective, randomized, controlled clinical pilot study

    PubMed Central

    2013-01-01

    Purpose Nondegradable steel-and titanium-based implants are commonly used in orthopedic surgery. Although they provide maximal stability, they are also associated with interference on imaging modalities, may induce stress shielding, and additional explantation procedures may be necessary. Alternatively, degradable polymer implants are mechanically weaker and induce foreign body reactions. Degradable magnesium-based stents are currently being investigated in clinical trials for use in cardiovascular medicine. The magnesium alloy MgYREZr demonstrates good biocompatibility and osteoconductive properties. The aim of this prospective, randomized, clinical pilot trial was to determine if magnesium-based MgYREZr screws are equivalent to standard titanium screws for fixation during chevron osteotomy in patients with a mild hallux valgus. Methods Patients (n=26) were randomly assigned to undergo osteosynthesis using either titanium or degradable magnesium-based implants of the same design. The 6 month follow-up period included clinical, laboratory, and radiographic assessments. Results No significant differences were found in terms of the American Orthopaedic Foot and Ankle Society (AOFAS) score for hallux, visual analog scale for pain assessment, or range of motion (ROM) of the first metatarsophalangeal joint (MTPJ). No foreign body reactions, osteolysis, or systemic inflammatory reactions were detected. The groups were not significantly different in terms of radiographic or laboratory results. Conclusion The radiographic and clinical results of this prospective controlled study demonstrate that degradable magnesium-based screws are equivalent to titanium screws for the treatment of mild hallux valgus deformities. PMID:23819489

  3. Magnesium industry overview

    SciTech Connect

    Clow, B.B.

    1996-10-01

    Magnesium products provide an excellent strength-to-weight ratio, good fatigue strength, high impact strength, good corrosion resistance, high-speed machinability, and good thermal and electrical conductivities. As a result, applications are expanding in almost every industry. Dozens of automotive components are now made of magnesium, including steering wheels, valve covers, and seat frames. Magnesium alloys are also used in computer housings, in-line roller skates, golf clubs, tennis racquets, and baseball bats. Good strength and stiffness at both room and elevated temperatures make magnesium alloys especially valuable for aerospace applications. This article presents an overview of magnesium technology, world production, increasing demand, and recycling.

  4. Magnesium Sulfate: Another Cause of a Solute Diuresis.

    PubMed

    Brown, Robert S

    2017-04-01

    In pregnant women, magnesium sulfate infusions are a treatment commonly used for preeclampsia and as a tocolytic agent. In this case report, a 33-year-old woman at 26 weeks of gestation received intravenous magnesium sulfate in Ringer's lactate solution and corticosteroids for preterm uterine contractions without preeclampsia. She developed polyuria of more than 18L in 48 hours, with urine chemistries documenting that magnesium sulfate contributed 30% of the solute in this massive isosthenuric diuresis. Therefore, magnesium sulfate should be added to the common solutes, glucose, sodium chloride, urea, and mannitol, as a cause of solute diureses. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  5. The efficacy of nebulized salbutamol, magnesium sulfate, and salbutamol/magnesium sulfate combination in moderate bronchiolitis.

    PubMed

    Kose, Mehmet; Ozturk, Mehmet Adnan; Poyrazoğlu, Hakan; Elmas, Tuba; Ekinci, Duygu; Tubas, Filiz; Kurt, Tuba; Goktas, Mehmet Akif

    2014-09-01

    The aim of this paper is to compare the effect of nebulized magnesium sulfate to nebulized salbutamol and salbutamol/magnesium sulfate on successful discharge from the emergency department. A total of 56 infants were included in this double-blinded, prospective study. Infants were grouped according to the nebulized treatment they received: group 1-salbutamol/normal saline, group 2-magnesium sulfate and normal saline, and group 3-salbutamol plus magnesium sulfate. Heart beat, bronchiolitis, clinical severity scores (CSS), and oxygen saturation of the patients were determined before and after nebulization (0, 1, 4 h). The patients were monitored for adverse reactions. Post-treatment mean CSS results were significantly lower than pre-treatment scores in all groups at 4 h with no significant difference within groups. CSS scores were lower in the salbutamol/magnesium sulfate group when compared with the magnesium sulfate and salbutamol groups (3.4 (2.4-4.3), 4.7 (3.8-5.7), 4.0 (3.2-4.3)). CSS were significantly lower than those from the magnesium sulfate group. Nebulized magnesium sulfate plus salbutamol may have additive effects for improving the short-term CSS.

  6. Measurement of double differential charged-particle emission cross sections for reactions induced by 26 MeV protons and FKK model analysis

    SciTech Connect

    Watanabe, Y.; Aoto, A.; Kashimoto, H.

    1994-06-01

    Double differential charged-particle emission cross sections of proton-induced reactions have been measured for {sup nat}C, {sup 27}Al, {sup nat}Si, {sup 98}Mo, {sup 106}Pd, {sup 159}Tb and {sup 181}Ta at energies around 26 MeV. Several (p,p{prime}) and (p,n) data for {sup 98}Mo and {sup 106}Pd in the incident energy range from 12 to 26 MeV are analysed in terms of the Feshbach-Kerman-Koonin model, in order to study preequilibrium nucleon emission from nucleon-induced reactions.

  7. Temperature dependent phase transformation in nano sized magnesium ferrite

    NASA Astrophysics Data System (ADS)

    Sumangala T., P.; Mahender, C.; Venkataramani, N.; Prasad, Shiva

    2015-06-01

    The phase transformation in nanosized stoichiometric magnesium ferrite is being discussed. It was shown by TGA/DSC that there exist two reactions (shown by exothermic peaks) in nano sized magnesium ferrite when synthesized by sol gel combustion synthesis. First one of these reactions resulted in the precipitation of α-Fe2O3 and a resultant spinel. The second reaction resulted in stoichiometric spinel from this two phase system.

  8. Enhanced Bacterial α(2,6)-Sialyltransferase Reaction through an Inhibition of Its Inherent Sialidase Activity by Dephosphorylation of Cytidine-5'-Monophosphate

    PubMed Central

    Kang, Ji-Yeon; Lim, Se-Jong; Kwon, Ohsuk; Lee, Seung-Goo; Kim, Ha Hyung; Oh, Doo-Byoung

    2015-01-01

    Bacterial α(2,6)-sialyltransferases (STs) from Photobacterium damsela, Photobacterium sp. JT-ISH-224, and P. leiognathi JT-SHIZ-145 were recombinantly expressed in Escherichia coli and their ST activities were compared directly using a galactosylated bi-antennary N-glycan as an acceptor substrate. In all ST reactions, there was an increase of sialylated glycans at shorter reaction times and later a decrease in prolonged reactions, which is related with the inherent sialidase activities of bacterial STs. These sialidase activities are greatly increased by free cytidine monophosphate (CMP) generated from a donor substrate CMP-N-acetylneuraminic acid (CMP-Neu5Ac) during the ST reactions. The decrease of sialylated glycans in prolonged ST reaction was prevented through an inhibition of sialidase activity by simple treatment of alkaline phosphatase (AP), which dephosphorylates CMP to cytidine. Through supplemental additions of AP and CMP-Neu5Ac to the reaction using the recombinant α(2,6)-ST from P. leiognathi JT-SHIZ-145 (P145-ST), the content of bi-sialylated N-glycan increased up to ~98% without any decrease in prolonged reactions. This optimized P145-ST reaction was applied successfully for α(2,6)-sialylation of asialofetuin, and this resulted in a large increase in the populations of multi-sialylated N-glycans compared with the reaction without addition of AP and CMP-Neu5Ac. These results suggest that the optimized reaction using the recombinant P145-ST readily expressed from E. coli has a promise for economic glycan synthesis and glyco-conjugate remodeling. PMID:26231036

  9. Enhanced Bacterial α(2,6)-Sialyltransferase Reaction through an Inhibition of Its Inherent Sialidase Activity by Dephosphorylation of Cytidine-5'-Monophosphate.

    PubMed

    Kang, Ji-Yeon; Lim, Se-Jong; Kwon, Ohsuk; Lee, Seung-Goo; Kim, Ha Hyung; Oh, Doo-Byoung

    2015-01-01

    Bacterial α(2,6)-sialyltransferases (STs) from Photobacterium damsela, Photobacterium sp. JT-ISH-224, and P. leiognathi JT-SHIZ-145 were recombinantly expressed in Escherichia coli and their ST activities were compared directly using a galactosylated bi-antennary N-glycan as an acceptor substrate. In all ST reactions, there was an increase of sialylated glycans at shorter reaction times and later a decrease in prolonged reactions, which is related with the inherent sialidase activities of bacterial STs. These sialidase activities are greatly increased by free cytidine monophosphate (CMP) generated from a donor substrate CMP-N-acetylneuraminic acid (CMP-Neu5Ac) during the ST reactions. The decrease of sialylated glycans in prolonged ST reaction was prevented through an inhibition of sialidase activity by simple treatment of alkaline phosphatase (AP), which dephosphorylates CMP to cytidine. Through supplemental additions of AP and CMP-Neu5Ac to the reaction using the recombinant α(2,6)-ST from P. leiognathi JT-SHIZ-145 (P145-ST), the content of bi-sialylated N-glycan increased up to ~98% without any decrease in prolonged reactions. This optimized P145-ST reaction was applied successfully for α(2,6)-sialylation of asialofetuin, and this resulted in a large increase in the populations of multi-sialylated N-glycans compared with the reaction without addition of AP and CMP-Neu5Ac. These results suggest that the optimized reaction using the recombinant P145-ST readily expressed from E. coli has a promise for economic glycan synthesis and glyco-conjugate remodeling.

  10. Magnesium in disease

    PubMed Central

    Wanner, Christoph

    2012-01-01

    Although the following text will focus on magnesium in disease, its role in healthy subjects during physical exercise when used as a supplement to enhance performance is also noteworthy. Low serum magnesium levels are associated with metabolic syndrome, Type 2 diabetes mellitus (T2DM) and hypertension; consequently, some individuals benefit from magnesium supplementation: increasing magnesium consumption appears to prevent high blood pressure, and higher serum magnesium levels are associated with a lower risk of developing a metabolic syndrome. There are, however, conflicting study results regarding magnesium administration with myocardial infarction with and without reperfusion therapy. There was a long controversy as to whether or not magnesium should be given as a first-line medication. As the most recent trials have not shown any difference in outcome, intravenous magnesium cannot be recommended in patients with myocardial infarction today. However, magnesium has its indication in patients with torsade de pointes and has been given successfully to patients with digoxin-induced arrhythmia or life-threatening ventricular arrhythmias. Magnesium sulphate as an intravenous infusion also has an important established therapeutic role in pregnant women with pre-eclampsia as it decreases the risk of eclamptic seizures by half compared with placebo. PMID:26069818

  11. Oxalate metabolism in magnesium-deficient rats.

    PubMed

    Rattan, V; Thind, S K; Jethi, R K; Sidhu, H; Nath, R

    1993-06-01

    Male weanling rats were maintained on magnesium-deficient diet for 30 d and compared with pair-fed control rats fed magnesium-supplemented diet. Magnesium deficiency led to slow growth and finally to a significant decrease in body weight (P < 0.001) accompanied by a significant hypomagnesaemia, hypomagnesuria and hyperoxaluria (P < 0.001 in each case) in experimental rats as compared to the control rats. Magnesium deficiency altered the glyoxylate metabolism in the liver and kidney mitochondria by significantly decreasing glyoxylate oxidation (by 26 per cent in liver and 17 per cent in kidney) and activity of alpha-ketoglutarate:glyoxylate carboligase enzyme (by 35 per cent in liver and 27 per cent in kidney) in the experimental animals. A significant increase in the specific activities of glycolic acid oxidase (P < 0.001) and glycolic acid dehydrogenase (P < 0.01) and a significant decrease in alanine transaminase (P < 0.01) was also observed in magnesium-deficient rats. No change in liver and kidney lactate dehydrogenase was observed. Thus magnesium deficiency in rats leads to accumulation of glyoxylate in the tissues, a part of which is converted into oxalate, thereby promoting hyperoxaluria.

  12. Magnesium degradation products: effects on tissue and human metabolism.

    PubMed

    Seitz, J-M; Eifler, R; Bach, Fr-W; Maier, H J

    2014-10-01

    Owing to their mechanical properties, metallic materials present a promising solution in the field of resorbable implants. The magnesium metabolism in humans differs depending on its introduction. The natural, oral administration of magnesium via, for example, food, essentially leads to an intracellular enrichment of Mg(2+) . In contrast, introducing magnesium-rich substances or implants into the tissue results in a different decomposition behavior. Here, exposing magnesium to artificial body electrolytes resulted in the formation of the following products: magnesium hydroxide, magnesium oxide, and magnesium chloride, as well as calcium and magnesium apatites. Moreover, it can be assumed that Mg(2+) , OH(-) ions, and gaseous hydrogen are also present and result from the reaction for magnesium in an aqueous environment. With the aid of physiological metabolic processes, the organism succeeds in either excreting the above mentioned products or integrating them into the natural metabolic process. Only a burst release of these products is to be considered a problem. A multitude of general tissue effects and responses from the Mg's degradation products is considered within this review, which is not targeting specific implant classes. Furthermore, common alloying elements of magnesium and their hazardous potential in vivo are taken into account.

  13. Regioselective synthesis of isotopically labeled Δ9-tetrahydrocannabinolic acid A (THCA-A-D3) by reaction of Δ9-tetrahydrocannabinol-D3 with magnesium methyl carbonate.

    PubMed

    Roth, Nadine; Wohlfarth, Ariane; Müller, Michael; Auwärter, Volker

    2012-10-10

    For the reliable quantification of Δ9-tetrahydrocannabinolic acid A (THCA-A), the biogenetic precursor of Δ9-tetrahydrocannabinol (THC), in biological matrices by LC-MS/MS and GC-MS(/MS), an isotopically labeled internal standard was synthesized starting from Δ9-tetrahydrocannabinol-D(3) (THC-D(3)). Synthesis strategy was based on a method reported by Mechoulam et al. in 1969 using magnesium methyl carbonate (MMC) as carboxylation reagent for the synthesis of cannabinoid acids. Preliminary experiments with THC to optimize yield of the product (THCA-A) resulted in the synthesis of the positional isomer tetrahydrocannabinolic acid B (THCA-B) as a byproduct. Using the optimized conditions for the desired isomer, THCA-A-D(3) was prepared and isolated with a yield of approx. 10% after two synthesis cycles. Isotope purity was estimated to be >99% by relative abundance of the molecular ions. The synthesized compound proved to be suitable as an internal standard for quantification of THCA-A in serum and hair samples of cannabis consumers.

  14. Superplasticity in Thermomechanically Processed High Magnesium Aluminum-Magnesium Alloys.

    DTIC Science & Technology

    1984-03-01

    California DTIC EECTE JL I 1984 THESIS SUPERPLASTICITY IN THERMOMECHANICALLY PROCESSED HIGH MAGNESIUM ALUMINUM-MAGNESIUM ALLOYS C:L by CD) John J. Becker...High Magnesium Aluminum- March 1984 Magnesium Alloys S. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(@) S. CONTRACT OR GRANT NUMBER(&) John J. Becker 9...magnesium, aluminum-magnesium alloys were investigated. The thermomechanical processing itself included warm rolling at 300°C to 94% reduction

  15. Study of the 27Al(n,2n)26Al reaction and its potential for ion-temperature measurements (abstract)

    NASA Astrophysics Data System (ADS)

    Wallner, A.; Chuvaev, S. V.; Filatenkov, A. A.; Ikeda, Y.; Kutschera, W.; Vonach, H.

    2001-01-01

    A detailed measurement of the 27Al(n,2n)26Al reaction cross sections was performed in the near-threshold region (Eth=13.54 MeV), and its possible applicability for ion temperature measurements was investigated. The production of the long-lived radionuclide 26Al (t1/2=7.2×105 a) is of considerable interest to the fusion reactor program. Particularly long-lived radionuclides may lead to a significant long-term waste-disposal. Al-containing materials and Si carbide are candidate materials for fusion-reactor systems. The Al(n,2n) reaction and the two step process 28Si(n,np+d)27Al(n,2n) are the dominating processes for the formation of 26Al in a fusion reactor.1 The 27Al(n,2n)26Al reaction is expected to vary strongly with neutron energy above threshold. An accurate description of the excitation function is necessary to estimate the production of 26Al in a typical D-T fusion environment. From the existing data on cross sections it was not possible to produce an unambiguous excitation function. We started therefore a project to determine this excitation function more accurately. It has been pointed out by Smither and Greenwood2 that the 27Al(n,2n)26Al reaction can be used as a monitor to determine the ion temperature in a D-T fusion plasma. This method makes use of the neutron energy distribution as a sensitive function of the plasma ion temperature. The temperature sensitivity is most pronounced if the excitation function is strongly nonlinear and if the threshold falls within the energy region of the emitted neutrons: For the 27Al(n,2n)26Al reaction the threshold lies at 13.54 MeV and the (n,2n) reaction is expected to a strongly varying function of the neutron energy near threshold. Al samples were irradiated with 14 MeV neutrons generated via the T(d,n)4He reaction at three different laboratories under different conditions. The produced 26Al was measured using the extremely sensitive method of accelerator mass spectrometry (AMS). 26Al/27Al isotope ratios as low as

  16. Magnesium in pregnancy.

    PubMed

    Dalton, Lynne M; Ní Fhloinn, Deirdre M; Gaydadzhieva, Gergana T; Mazurkiewicz, Ola M; Leeson, Heather; Wright, Ciara P

    2016-09-01

    Magnesium deficiency is prevalent in women of childbearing age in both developing and developed countries. The need for magnesium increases during pregnancy, and the majority of pregnant women likely do not meet this increased need. Magnesium deficiency or insufficiency during pregnancy may pose a health risk for both the mother and the newborn, with implications that may extend into adulthood of the offspring. The measurement of serum magnesium is the most widely used method for determining magnesium levels, but it has significant limitations that have both hindered the assessment of deficiency and affected the reliability of studies in pregnant women. Thus far, limited studies have suggested links between magnesium inadequacy and certain conditions in pregnancy associated with high mortality and morbidity, such as gestational diabetes, preterm labor, preeclampsia, and small for gestational age or intrauterine growth restriction. This review provides recommendations for further study and improved testing using measurement of red cell magnesium. Pregnant women should be counseled to increase their intake of magnesium-rich foods such as nuts, seeds, beans, and leafy greens and/or to supplement with magnesium at a safe level. © The Author(s) 2016. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  17. IMPACT OF A REVISED {sup 25}Mg(p, {gamma}){sup 26}Al REACTION RATE ON THE OPERATION OF THE Mg-Al CYCLE

    SciTech Connect

    Straniero, O.; Cristallo, S.; Imbriani, G.; DiLeva, A.; Limata, B.; Strieder, F.; Bemmerer, D.; Broggini, C.; Caciolli, A.; Corvisiero, P.; Costantini, H.; Lemut, A.; Formicola, A.; Gustavino, C.; Junker, M.; Elekes, Z.; Fueloep, Zs.; Gyuerky, Gy.; Gervino, G.; Guglielmetti, A.; and others

    2013-02-15

    Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H-burning regions. In particular, low-energy nuclear resonances in the {sup 25}Mg(p, {gamma}){sup 26}Al reaction affect the production of radioactive {sup 26}Al{sup gs} as well as the resulting Mg/Al abundance ratio. Reliable estimations of these quantities require precise measurements of the strengths of low-energy resonances. Based on a new experimental study performed at the Laboratory for Underground Nuclear Astrophysics, we provide revised rates of the {sup 25}Mg(p, {gamma}){sup 26}Al{sup gs} and the {sup 25}Mg(p, {gamma}){sup 26}Al {sup m} reactions with corresponding uncertainties. In the temperature range 50-150 MK, the new recommended rate of {sup 26}Al {sup m} production is up to five times higher than previously assumed. In addition, at T = 100 MK, the revised total reaction rate is a factor of two higher. Note that this is the range of temperature at which the Mg-Al cycle operates in a H-burning zone. The effects of this revision are discussed. Due to the significantly larger {sup 25}Mg(p, {gamma}){sup 26}Al {sup m} rate, the estimated production of {sup 26}Al{sup gs} in H-burning regions is less efficient than previously obtained. As a result, the new rates should imply a smaller contribution from Wolf-Rayet stars to the galactic {sup 26}Al budget. Similarly, we show that the asymptotic giant branch (AGB) extra-mixing scenario does not appear able to explain the most extreme values of {sup 26}Al/{sup 27}Al, i.e., >10{sup -2}, found in some O-rich presolar grains. Finally, the substantial increase of the total reaction rate makes the hypothesis of self-pollution by massive AGBs a more robust explanation for the Mg-Al anticorrelation observed in globular-cluster stars.

  18. Kinetic studies of the reverse reaction catalysed by adenosine triphosphate–creatine phosphotransferase. The inhibition by magnesium ions and adenosine diphosphate

    PubMed Central

    Morrison, J. F.; O'Sullivan, W. J.

    1965-01-01

    1. Kinetic investigations of the reaction catalysed by ATP–creatine phosphotransferase have been carried out. 2. No firm conclusions could be reached about the reaction of Mg2+ at the nucleotide-binding site of the enzyme. The value of the kinetic constant for this reaction depends on the value used for the apparent stability constant of the metal ion–nucleotide complex and, to a smaller extent, on the method of plotting the results. 3. At higher concentrations Mg2+ is a non-competitive inhibitor of the enzyme with respect to both MgADP− and phosphocreatine. 4. ADP3− is a competitive inhibitor of the enzyme with respect to MgADP− and a non-competitive inhibitor with respect to phosphocreatine. 5. The concentration of phosphocreatine has little, if any, effect on the kinetic constants for the nucleotide reactants. PMID:14342234

  19. Magnesium Ethylenediamine Borohydride as Solid-State Electrolyte for Magnesium Batteries.

    PubMed

    Roedern, Elsa; Kühnel, Ruben-Simon; Remhof, Arndt; Battaglia, Corsin

    2017-04-07

    Solid-state magnesium ion conductors with exceptionally high ionic conductivity at low temperatures, 5 × 10(-8) Scm(-1) at 30 °C and 6 × 10(-5) Scm(-1) at 70 °C, are prepared by mechanochemical reaction of magnesium borohydride and ethylenediamine. The coordination complexes are crystalline, support cycling in a potential window of 1.2 V, and allow magnesium plating/stripping. While the electrochemical stability, limited by the ethylenediamine ligand, must be improved to reach competitive energy densities, our results demonstrate that partially chelated Mg(2+) complexes represent a promising platform for the development of an all-solid-state magnesium battery.

  20. Magnesium Ethylenediamine Borohydride as Solid-State Electrolyte for Magnesium Batteries

    NASA Astrophysics Data System (ADS)

    Roedern, Elsa; Kühnel, Ruben-Simon; Remhof, Arndt; Battaglia, Corsin

    2017-04-01

    Solid-state magnesium ion conductors with exceptionally high ionic conductivity at low temperatures, 5 × 10-8 Scm-1 at 30 °C and 6 × 10-5 Scm-1 at 70 °C, are prepared by mechanochemical reaction of magnesium borohydride and ethylenediamine. The coordination complexes are crystalline, support cycling in a potential window of 1.2 V, and allow magnesium plating/stripping. While the electrochemical stability, limited by the ethylenediamine ligand, must be improved to reach competitive energy densities, our results demonstrate that partially chelated Mg2+ complexes represent a promising platform for the development of an all-solid-state magnesium battery.

  1. Magnesium Ethylenediamine Borohydride as Solid-State Electrolyte for Magnesium Batteries

    PubMed Central

    Roedern, Elsa; Kühnel, Ruben-Simon; Remhof, Arndt; Battaglia, Corsin

    2017-01-01

    Solid-state magnesium ion conductors with exceptionally high ionic conductivity at low temperatures, 5 × 10−8 Scm−1 at 30 °C and 6 × 10−5 Scm−1 at 70 °C, are prepared by mechanochemical reaction of magnesium borohydride and ethylenediamine. The coordination complexes are crystalline, support cycling in a potential window of 1.2 V, and allow magnesium plating/stripping. While the electrochemical stability, limited by the ethylenediamine ligand, must be improved to reach competitive energy densities, our results demonstrate that partially chelated Mg2+ complexes represent a promising platform for the development of an all-solid-state magnesium battery. PMID:28387305

  2. Magnesium in obstetrics.

    PubMed

    James, M F M

    2010-06-01

    Magnesium is a critical physiological ion, and magnesium deficiency might contribute to the development of pre-eclampsia, to impaired neonatal development and to metabolic problems extending into adult life. Pharmacologically, magnesium is a calcium antagonist with substantial vasodilator properties but without myocardial depression. Cardiac output usually increases following magnesium administration, compensating for the vasodilatation and minimising hypotension. Neurologically, the inhibition of calcium channels and antagonism of the N-methyl-d-aspartic acid (NMDA) receptor raises the possibility of neuronal protection, and magnesium administration to women with premature labour may decrease the incidence of cerebral palsy. It is the first-line anticonvulsant for the management of pre-eclampsia and eclampsia, and it should be administered to all patients with severe pre-eclampsia or eclampsia. Magnesium is a moderate tocolytic but the evidence for its effectiveness remains disputed. The side effects of magnesium therapy are generally mild but the major hazard of magnesium therapy is neuromuscular weakness. 2009 Elsevier Ltd. All rights reserved.

  3. Laser-induced Magnesium Production from Magnesium Oxide for Renewable Magnesium Energy Cycle.

    NASA Astrophysics Data System (ADS)

    Liao, Shi-Hua; Yabe, Takashi; Baasandash, Choijil; Sato, Yuji; Ichikawa, Masashi; Nakatsuka, Masashi; Fukushima, Chika; Uchida, Shigeaki; Ohkubo, Tomomasa

    2010-10-01

    We succeeded in reducing magnesium [Mg] from magnesium oxide [MgO] by laser irradiation. The laser-induced vapor temperature was measured to be approximately 5000 K on the irradiating spot, where MgO separated into Mg and oxygen [O] atoms through thermal dissociation. The Mg vapor was intercepted a cooper plate, forming solid deposits on it. However, the presence of oxygen, resulting from MgO dissociation, leads to Mg oxidization in the course of vapor cooling. The deoxidization process results in lower Mg fraction in the deposits and degrades energy recovery efficiency from laser irradiation. To quench this recombination, we also employed silicon as reducing agents to capture oxygen in favor of Mg extraction. In these experiments, the molar ratio effect (MgO:Si = 1:0-1) on the magnesium fractions and energy efficiencies were measured by means of a chemical reaction. The maximal energy efficiency, %, was obtained at the ratio of MgO:Si = 1:0.5. This ratio is lower than that of the Pidgeon process with Mg:Si = 1:1 resulting in a lower energy efficiency of %. This implies laser-induced Mg production is a economical process of using reducing agents with large throughput. The usage of laser radiation generated from solar energy for Mg metallurgy will significantly reduce CO2 emission.

  4. Parenteral magnesium tolerance testing in the evaluation of magnesium deficiency.

    PubMed

    Ryzen, E; Elbaum, N; Singer, F R; Rude, R K

    1985-01-01

    Magnesium deficiency is a common clinical condition, frequently present even with normal serum magnesium (S-Mg) concentrations. We have studied retention of a low-dose (0.2 mEq/kg lean body weight), intravenously administered magnesium load in 6 hypomagnesemic patients and 18 normomagnesemic alcoholics as compared with 16 normal subjects. Both normomagnesemic and hypomagnesemic subjects retained significantly greater amounts of the administered magnesium than did the normal subjects. In patients who were restudied following parenteral magnesium repletion, retention of the magnesium load normalized. We conclude that increased retention of a magnesium load is a more sensitive index of magnesium deficiency than is the S-Mg concentration, and suggest that low-dose magnesium tolerance testing be used more frequently as a clinical tool in the evaluation of states of normomagnesemic magnesium deficiency.

  5. Chiral 2,6-bis(oxazolinyl)pyridine-rare earth metal complexes as catalysts for highly enantioselective 1,3-dipolar cycloaddition reactions of 2-benzopyrylium-4-olates.

    PubMed

    Suga, Hiroyuki; Inoue, Kei; Inoue, Shuichi; Kakehi, Akikazu; Shiro, Motoo

    2005-01-07

    Significant levels of enantioselectivity were obtained in 1,3-dipolar cycloadditions of 2-benzopyrylium-4-olate generated from the Rh(2)(OAc)(4)-catalyzed decomposition of o-methoxycarbonyl-alpha-diazoacetophenone. This reaction utilized chiral 2,6-bis(oxazolinyl)pyridine (Pybox)--rare earth metal triflate complexes as chiral Lewis acid catalysts. The reactions with several benzyloxyacetaldehyde derivatives catalyzed by a Sc(III)--Pybox-i-Pr complex (10 mol %) proceeded smoothly to yield endo-adducts selectively with high enantioselectivity (up to 93% ee). For the reaction with benzyl pyruvate, the Sc(III)-Pybox-i-Pr complex (10 mol %) catalyzed the reaction effectively in the presence of trifluoroacetic acid (10 mol %) to yield an exo-adduct with both high diastereo- and enantioselectivity (94% ee). This catalytic system was efficiently applied to the reactions with several other alpha-keto esters with high exo- and enantioselectivities (up to 95% ee). In contrast to the reaction with carbonyl compounds, Yb(III)--Pybox-Ph complex (10 mol %) was found to be effective to obtain high enantioselectivity (96% ee) of diastereoselectively produced exo-cycloadduct in the reaction with 3-acryloyl-2-oxazolidinone.

  6. Superior catalytic activity derived from a two-dimensional Ti3C2 precursor towards the hydrogen storage reaction of magnesium hydride.

    PubMed

    Liu, Yongfeng; Du, Hufei; Zhang, Xin; Yang, Yaxiong; Gao, Mingxia; Pan, Hongge

    2016-01-14

    The superior catalytic effects derived from a 2D Ti3C2 (MXene), synthesized by the exfoliation of Ti3AlC2 powders, towards the hydrogen storage reaction of MgH2 were demonstrated. The 5 wt% Ti3C2-containing MgH2 releases 6.2 wt% H2 within 1 min at 300 °C and absorbs 6.1 wt% H2 within 30 s at 150 °C, exhibiting excellent dehydrogenation/hydrogenation kinetics.

  7. Direct total cross section measurement of the 16O(α,γ)20Ne reaction at Ec.m.=2.26 MeV

    NASA Astrophysics Data System (ADS)

    Hager, U.; Brown, J. R.; Buchmann, L.; Carmona-Gallardo, M.; Erikson, L.; Fallis, J.; Greife, U.; Hutcheon, D.; Ottewell, D.; Ruiz, C.; Sjue, S.; Vockenhuber, C.

    2011-08-01

    In stellar helium burning, 16O represents the endpoint of the helium-burning sequence due to the low rate of 16O(α,γ)20Ne. We present a new direct measurement of the total capture reaction rate of 16O(α,γ)20Ne at Ec.m.=2.26MeV employing the DRAGON recoil separator. For the first time, the total S factor and its contributing direct capture transitions could be determined in one experiment.

  8. Computing the cross sections of nuclear reactions with nuclear clusters emission for proton energies between 30 MeV and 2.6 GeV

    SciTech Connect

    Korovin, Yu. A.; Maksimushkina, A. V. Frolova, T. A.

    2016-12-15

    The cross sections of nuclear reactions involving emission of clusters of light nuclei in proton collisions with a heavy-metal target are computed for incident-proton energies between 30 MeV and 2.6 GeV. The calculation relies on the ALICE/ASH and CASCADE/INPE computer codes. The parameters determining the pre-equilibrium cluster emission are varied in the computation.

  9. Magnesium and depression.

    PubMed

    Serefko, Anna; Szopa, Aleksandra; Poleszak, Ewa

    2016-03-01

    Magnesium is one of the most important elements in the human body and is involved in a number of biochemical processes crucial for the proper functioning of the cardiovascular, alimentary, endocrine, and osteoarticular systems. It also plays a vital modulatory role in brain biochemistry, influencing several neurotransmission pathways associated with the development of depression. Personality changes, including apathy, depression, agitation, confusion, anxiety, and delirium are observed when there is a deficiency of this element. Rodents receiving a diet deficient in magnesium displayed depressive behaviour that was reversed by antidepressant drugs. Poor nutrition, gastrointestinal and renal diseases, insulin resistance and/or type 2 diabetes, alcoholism, stress, and certain medications may lead to magnesium deficiency. Since the extracellular concentration of magnesium ions may not reflect their intracellular level, none of the current methods of evaluating magnesium status is regarded as satisfactory. The mood-improving potential of magnesium compounds have been confirmed by the results of numerous pre-clinical and clinical studies. It seems that magnesium supplementation is well-tolerated and enhances the efficacy of conventional antidepressant treatments, and as such could be a valuable addition to the standard treatments for depression, although differences in bioavailability between inorganic and organic compounds should be taken into consideration.

  10. Blood compatibility of magnesium and its alloys.

    PubMed

    Feyerabend, Frank; Wendel, Hans-Peter; Mihailova, Boriana; Heidrich, Stefanie; Agha, Nezha Ahmad; Bismayer, Ulrich; Willumeit-Römer, Regine

    2015-10-01

    Blood compatibility analysis in the field of biomaterials is a highly controversial topic. Especially for degradable materials like magnesium and its alloys no established test methods are available. The purpose of this study was to apply advanced test methodology for the analysis of degrading materials to get a mechanistic insight into the corrosion process in contact with human blood and plasma. Pure magnesium and two magnesium alloys were analysed in a modified Chandler-Loop setup. Standard clinical parameters were determined, and a thorough analysis of the resulting implant surface chemistry was performed. The contact of the materials to blood evoked an accelerated inflammatory and cell-induced osteoconductive reaction. Corrosion products formed indicate a more realistic, in vivo like situation. The active regulation of corrosion mechanisms of magnesium alloys by different cell types should be more in the focus of research to bridge the gap between in vitro and in vivo observations and to understand the mechanism of action. This in turn could lead to a better acceptance of these materials for implant applications. The presented study deals with the first mechanistic insights during whole human blood contact and its influence on a degrading magnesium-based biomaterial. The combination of clinical parameters and corrosion layer analysis has been performed for the first time. It could be of interest due to the intended use of magnesium-based stents and for orthopaedic applications for clinical applications. An interest for the readers of Acta Biomaterialia may be given, as one of the first clinically approved magnesium-based devices is a wound-closure device, which is in direct contact with blood. Moreover, for orthopaedic applications also blood contact is of high interest. Although this is not the focus of the manuscript, it could help to rise awareness for potential future applications. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All

  11. Magnesium(I) Dimers Bearing Tripodal Diimine-Enolate Ligands: Proficient Reagents for the Controlled Reductive Activation of CO2 and SO2.

    PubMed

    Boutland, Aaron J; Pernik, Indrek; Stasch, Andreas; Jones, Cameron

    2015-10-26

    The first examples of magnesium(I) dimers bearing tripodal ligands, [(Mg{κ(3) -N,N',O-(ArNCMe)2 (OCCPh2 )CH})2 ] [Ar=2,6-iPr2 C6 H3 (Dip) 7, 2,6-Et2 C6 H3 (Dep) 8, or mesityl (Mes) 9] have been prepared by post-synthetic modification of the β-diketiminato ligands of previously reported magnesium(I) systems, using diphenylketene, OCCPh2 . In contrast, related reactions between β-diketiminato magnesium(I) dimers and the isoelectronic ketenimine, MesNCCPh2 , resulted in reductive insertion of the substrate into the MgMg bond of the magnesium(I) reactant, and formation of [{(Nacnac)Mg}2 {μ-κ(2) -N,C-(Mes)NCCPh2 }] (Nacnac=[(ArNCMe)2 CH](-) ; Ar=Dep 10 or Mes 11). Reactions of the four-coordinate magnesium(I) dimer 8 with excess CO2 are readily controlled, and cleanly give carbonate [(LMg)2 (μ-κ(2) :κ(2) -CO3 )] 12 (L=[κ(3) -N,N',O-(DepNCMe)2 (OCCPh2 )CH](-) ; thermodynamic product), or oxalate [(LMg)2 (μ-κ(2) :κ(2) -C2 O4 )] 13 (kinetic product), depending on the reaction temperature. Compound 12 and CO are formed by reductive disproportionation of CO2 , whereas 13 results from reductive coupling of two molecules of the gas. Treatment of 8 with an excess of N2 O cleanly gives the μ-oxo complex [(LMg)2 (μ-O)] 14, which reacts facilely with CO2 to give 12. This result presents the possibility that 14 is an intermediate in the formation of 12 from the reaction of 8 and CO2 . In contrast to its reactions with CO2 , 8 reacts with SO2 over a wide temperature range to give only one product; the first example of a magnesium dithionite complex, [(LMg)2 (μ-κ(2) :κ(2) -S2 O4 )] 16, which is formed by reductive coupling of two molecules of SO2 , and is closely related to f-block metal dithionite complexes derived from similar SO2 reductive coupling processes. On the whole, this study strengthens previously proposed analogies between the reactivities of magnesium(I) systems and low-valent f-block metal complexes, especially with respect to small

  12. High power rechargeable magnesium/iodine battery chemistry

    PubMed Central

    Tian, Huajun; Gao, Tao; Li, Xiaogang; Wang, Xiwen; Luo, Chao; Fan, Xiulin; Yang, Chongyin; Suo, Liumin; Ma, Zhaohui; Han, Weiqiang; Wang, Chunsheng

    2017-01-01

    Rechargeable magnesium batteries have attracted considerable attention because of their potential high energy density and low cost. However, their development has been severely hindered because of the lack of appropriate cathode materials. Here we report a rechargeable magnesium/iodine battery, in which the soluble iodine reacts with Mg2+ to form a soluble intermediate and then an insoluble final product magnesium iodide. The liquid–solid two-phase reaction pathway circumvents solid-state Mg2+ diffusion and ensures a large interfacial reaction area, leading to fast reaction kinetics and high reaction reversibility. As a result, the rechargeable magnesium/iodine battery shows a better rate capability (180 mAh g−1 at 0.5 C and 140 mAh g−1 at 1 C) and a higher energy density (∼400 Wh kg−1) than all other reported rechargeable magnesium batteries using intercalation cathodes. This study demonstrates that the liquid–solid two-phase reaction mechanism is promising in addressing the kinetic limitation of rechargeable magnesium batteries. PMID:28071666

  13. High power rechargeable magnesium/iodine battery chemistry

    NASA Astrophysics Data System (ADS)

    Tian, Huajun; Gao, Tao; Li, Xiaogang; Wang, Xiwen; Luo, Chao; Fan, Xiulin; Yang, Chongyin; Suo, Liumin; Ma, Zhaohui; Han, Weiqiang; Wang, Chunsheng

    2017-01-01

    Rechargeable magnesium batteries have attracted considerable attention because of their potential high energy density and low cost. However, their development has been severely hindered because of the lack of appropriate cathode materials. Here we report a rechargeable magnesium/iodine battery, in which the soluble iodine reacts with Mg2+ to form a soluble intermediate and then an insoluble final product magnesium iodide. The liquid-solid two-phase reaction pathway circumvents solid-state Mg2+ diffusion and ensures a large interfacial reaction area, leading to fast reaction kinetics and high reaction reversibility. As a result, the rechargeable magnesium/iodine battery shows a better rate capability (180 mAh g-1 at 0.5 C and 140 mAh g-1 at 1 C) and a higher energy density (~400 Wh kg-1) than all other reported rechargeable magnesium batteries using intercalation cathodes. This study demonstrates that the liquid-solid two-phase reaction mechanism is promising in addressing the kinetic limitation of rechargeable magnesium batteries.

  14. High power rechargeable magnesium/iodine battery chemistry

    DOE PAGES

    Tian, Huajun; Gao, Tao; Li, Xiaogang; ...

    2017-01-10

    Rechargeable magnesium batteries have attracted considerable attention because of their potential high energy density and low cost. However, their development has been severely hindered because of the lack of appropriate cathode materials. Here we report a rechargeable magnesium/iodine battery, in which the soluble iodine reacts with Mg2+ to form a soluble intermediate and then an insoluble final product magnesium iodide. The liquid–solid two-phase reaction pathway circumvents solid-state Mg2+ diffusion and ensures a large interfacial reaction area, leading to fast reaction kinetics and high reaction reversibility. As a result, the rechargeable magnesium/iodine battery shows a better rate capability (180 mAh g–1more » at 0.5 C and 140 mAh g–1 at 1 C) and a higher energy density (~400 Wh kg–1) than all other reported rechargeable magnesium batteries using intercalation cathodes. As a result, this study demonstrates that the liquid–solid two-phase reaction mechanism is promising in addressing the kinetic limitation of rechargeable magnesium batteries.« less

  15. Magnesium battery disposal characteristics

    NASA Astrophysics Data System (ADS)

    Soffer, Louis; Atwater, Terrill

    1994-12-01

    This study assesses the disposal characteristics of U.S. Army procured military magnesium batteries under current Resource Conservation and Recovery Act (RCRA) hazardous waste identification regulations administered by the U.S. Environmental Protection Agency. Magnesium batteries were tested at 100, 50, 10 and 0 percent remaining state of charge. Present findings indicate that magnesium batteries with less than 50 percent remaining charge do not exceed the federal regulatory limit of 5.0 mg/L for chromium. All other RCRA contaminates were below regulatory limits at all levels of remaining charge. Assay methods, findings, disposal requirements and design implications are discussed.

  16. Castability of Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Bowles, A. L.; Han, Q.; Horton, J. A.

    There is intense research effort into the development of high pressure die cast-able creep resistant magnesium alloys. One of the difficulties encountered in magnesium alloy development for creep resistance is that many additions made to improve the creep properties have reportedly resulted in alloys that are difficult to cast. It is therefore important to have an understanding of the effect of alloying elements on the castability. This paper gives a review of the state of the knowledge of the castability of magnesium alloys.

  17. Magnesium toxicosis in two horses.

    PubMed

    Henninger, R W; Horst, J

    1997-07-01

    Magnesium sulfate, a saline laxative, is often used for treatment of intestinal impactions in horses. Clinical signs of hypermagnesemia are an uncommon complication following oral administration of magnesium sulfate. Overdose of magnesium sulfate in combination with renal insufficiency, hypocalcemia, or compromise of intestinal integrity may predispose horses to magnesium toxicosis. Establishment of diuresis with fluids and IV administration of calcium may provide successful treatment of magnesium toxicosis in horses.

  18. Magnesium inhibition of calcite dissolution kinetics

    SciTech Connect

    Arvidson, Rolf S.; Collier, Martin; Davis, Kevin J.; Vinson, Michael D.; Amonette, James E.; Luttge, Andreas

    2006-02-01

    We present evidence of inhibition of calcite dissolution by dissolved magnesium through direct observations of the (104) surface using atomic force microscopy (AFM) and vertical scanning interferometry (VSI). Far from equilibrium, the pattern of magnesium inhibition is dependent on solution composition and specific to surface step geometry. In CO2-free solutions (pH 8.8), dissolved magnesium brings about little inhibition even at concentrations of 0.8 x 10-3 molal. At the same pH, magnesium concentrations of less than 0.05 x 10-3 molal in carbonate-buffered solutions generate significant inhibition, although no changes in surface and etch pit morphology are observed. As concentrations exceed magnesite saturation, the dissolution rate shows little additional decrease; however, selective pinning of step edges results in unique etch-pit profiles, seen in both AFM and VSI datasets. Despite the decreases in step velocity, magnesium addition in carbonated solutions also appears to activate the surface by increasing the nucleation rate of new defects. These relationships suggest that the modest depression of the bulk rate measured by VSI reflects a balance between competing reaction mechanisms that simultaneously depress the rate through selective inhibition of step movement, but also enhance reactivity on terraces by lowering the energy barrier to new etch-pit formation.

  19. Recent data on the evaluation of magnesium bioavailability in humans.

    PubMed

    Benech, H; Grognet, J M

    1995-09-01

    Assessment of the bioavailability of exogenous ions present in a large amounts in the body, such as magnesium, cannot be performed by the conventional measurement of plasma levels after intravenous and/or oral administration. In the case of magnesium, this is emphasized by the fact that plasma levels are quickly regulated, mainly by the kidney and in storage compartments such as bone, after exogenous administration. Magnesium bioavailability and absorption are studied by indirect methods or by using radioactive or stable isotopes as tracers. Indirect methods are the metabolic balance method and comparison of urinary excretion between a treatment and a placebo period, often after magnesium load. However, the former only measures magnesium absorption and the latter is subject to the fragile balance of magnesium urinary excretion. Isotope studies, in particular with stable isotope probes, have benefited from the developments in mass spectrometry, such as inductively coupled plasma mass spectrometry (ICP-MS). It is possible to follow exogenous magnesium in plasma after oral and intravenous administrations using 25Mg and 26Mg as tracers, and to calculate the absolute bioavailability of magnesium.

  20. Thermal Stability of Magnesium Silicide/Nickel Contacts

    NASA Astrophysics Data System (ADS)

    de Boor, J.; Droste, D.; Schneider, C.; Janek, J.; Mueller, E.

    2016-10-01

    Magnesium silicide-based materials are a very promising class of thermoelectric materials with excellent potential for thermoelectric waste heat recovery. For the successful application of magnesium silicide-based thermoelectric generators, the development of long-term stable contacts with low contact resistance is as important as material optimization. We have therefore studied the suitability of Ni as a contact material for magnesium silicide. Co-sintering of magnesium silicide and Ni leads to the formation of a stable reaction layer with low electrical resistance. In this paper we show that the contacts retain their low electrical contact resistance after annealing at temperatures up to 823 K for up to 168 h. By employing scanning electron microscope analysis and time-of-flight (ToF)-secondary ion mass spectrometry, we can further show that elemental diffusion is occurring to a very limited extent. This indicates long-term stability under practical operation conditions for magnesium silicide/nickel contacts.

  1. Magnesium for automotive applications

    SciTech Connect

    VanFleteren, R.

    1996-05-01

    Die cast magnesium parts are rapidly replacing steel and aluminum structural components in automotive applications, as design engineers seek to reduce assembly costs, raise fuel efficiency, and improve safety. Dozens of automotive components are now die cast from magnesium alloys, including seat stanchions, valve covers, steering wheels, and a variety of steering column components. Because of their excellent castability, complex magnesium die castings can sometimes consolidate several components and eliminate assembly steps. Highly ductile magnesium alloys such as AM60B (6% aluminum) and AM50A (5% aluminum) are important in helping to meet automotive industry crash-energy requirements for car seating and steering components. AZ91D (9% aluminum, 1% zinc) alloys are making removable rear seats in new minivans much easier to handle.

  2. Magnesium blood test

    MedlinePlus

    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 ...

  3. Preparation and hydriding behavior of magnesium metal clusters formed in low-temperature cocondensation: application of magnesium for hydrogen storage

    SciTech Connect

    Imamura, H.; Nobunaga, T.; Kawahigashi, M.; Tsuchiya, S.

    1984-08-01

    Magnesium metal clusters formed in low-temperature matrices were investigated with a view to forming the metal hydride. In practice, magnesium readily absorbed large amounts of hydrogen under more moderate conditions (P/sub H/sub 2// = 460 torr, T = 200-250/sup 0/C) when it had been transformed into tetrahydrofuran- (THF-) solvated small particles formed by the cocondensation reaction of magnesium atoms with THF molecules at -196/sup 0/C. To elucidate the characteristics of hydrogen sorption of Mg-THF, a comparative study with pure magnesium powder was carried out. It is believed from the H/sub 2/-D/sub 2/ isotope scrambling measurements that the high activity of the present Mg-THF system for hydrogen absorption is due to a rapid surface process in comparison with the case of the pure magnesium. This identification is reinforced by the employment of surface modification. 19 references, 2 figures, 1 table.

  4. Rechargeable Magnesium Power Cells

    NASA Technical Reports Server (NTRS)

    Koch, Victor R.; Nanjundiah, Chenniah; Orsini, Michael

    1995-01-01

    Rechargeable power cells based on magnesium anodes developed as safer alternatives to high-energy-density cells like those based on lithium and sodium anodes. At cost of some reduction in energy density, magnesium-based cells safer because less susceptible to catastrophic meltdown followed by flames and venting of toxic fumes. Other advantages include ease of handling, machining, and disposal, and relatively low cost.

  5. Interstellar magnesium abundances

    NASA Technical Reports Server (NTRS)

    Murray, M. J.; Dufton, P. L.; Hibbert, A.; York, D. G.

    1984-01-01

    An improved evaluation of the Mg II 1240 A doublet oscillator strength is used in conjunction with recently published Copernicus observations to derive accurate Mg II column densities toward 74 stars. These imply an average of 40 percent of interstellar magnesium is in the gaseous phase. Magnesium depletion is examined as a function of various interstellar extinction and density parameters, and the results are briefly discussed in terms of current depletion theories.

  6. Magnesium and cardiovascular system.

    PubMed

    Shechter, Michael

    2010-06-01

    Hypomagnesemia is common in hospitalized patients, especially in the elderly with coronary artery disease (CAD) and/or those with chronic heart failure. Hypomagnesemia is associated with an increased incidence of diabetes mellitus, metabolic syndrome, mortality rate from CAD and all causes. Magnesium supplementation improves myocardial metabolism, inhibits calcium accumulation and myocardial cell death; it improves vascular tone, peripheral vascular resistance, afterload and cardiac output, reduces cardiac arrhythmias and improves lipid metabolism. Magnesium also reduces vulnerability to oxygen-derived free radicals, improves human endothelial function and inhibits platelet function, including platelet aggregation and adhesion, which potentially gives magnesium physiologic and natural effects similar to adenosine-diphosphate inhibitors such as clopidogrel. The data regarding its use in patients with acute myocardial infarction (AMI) is conflicting. Although some previous, relatively small randomized clinical trials demonstrated a remarkable reduction in mortality when administered to relatively high risk AMI patients, two recently published large-scale randomized clinical trials (the Fourth International Study of Infarct Survival and Magnesium in Coronaries) failed to show any advantage of intravenous magnesium over placebo. Nevertheless, there are theoretical potential benefits of magnesium supplementation as a cardioprotective agent in CAD patients, as well as promising results from previous work in animal and humans. These studies are cost effective, easy to handle and are relatively free of adverse effects, which gives magnesium a role in treating CAD patients, especially high-risk groups such as CAD patients with heart failure, the elderly and hospitalized patients with hypomagnesemia. Furthermore, magnesium therapy is indicated in life-threatening ventricular arrhythmias such as Torsades de Pointes and intractable ventricular tachycardia.

  7. Synthesis and characterization of magnesium oxide supported catalysts with a meso-macropore structure.

    PubMed

    Kim, Sang Woo; Kim, Inho; Moon, Dong Ju

    2013-08-01

    Nanostructured magnesium oxide catalyst support materials with controlled morphology and size were synthesized from a supercritical carbon dioxide/ethanol solution via chemical reaction of soluble precursors and subsequent thermal decomposition. Leaf-like magnesium hydroxide precursors with high specific surface area were formed by a low-temperature chemical reaction at below 140 degrees C, while magnesium carbonate cubes with a very low surface area less than 3.3 m2/g were formed by temperature-induced phase transition from a loose to a dense structure during carbonation reaction at above 150 degrees C. The specific surface area has significantly increased higher than 90 m2/g due to the creation of highly porous MgO cubes with mesopore structure formed after thermal decomposition of the magnesium carbonate precursors. Ni-magnesium oxide catalysts with bimodal pore structure were finally formed by the consequence of packing heterogeneity of the porous magnesium oxides with different morphologies and sizes.

  8. Magnesium for Future Autos

    SciTech Connect

    Nyberg, Eric A.; Luo, Alan A.; Sadayappan, Kumar; Shi, Wenfang

    2008-10-01

    In the quest for better fuel economy and improved environmental performance, magnesium may well become a metal of choice for constructing lighter, more efficient vehicles. Magnesium is the lightest structural metal, yet it has a high strength-to-weight ratio makes it comparable to steel in many applications. The world’s automakers already use magnesium for individual components. But new alloys and processing methods are needed before the metal can become economically and technologically feasible as a major automotive structural material. This article will explore the formation, challenges and initial results of an international collaboration—the Magnesium Front End Research and Development (MFERD) project—that is leveraging the expertise and resources of Canada, China and the United States to advance the creation of magnesium-intensive vehicles. The MFERD project aims to develop the enabling technologies and knowledge base that will lead to a vehicles that are 50-60 percent lighter, equally affordable, more recyclable and of equal or better quality when compared to today’s vehicles. Databases of information also will be captured in models to enable further alloy and manufacturing process optimization. Finally, a life-cycle analysis of the magnesium used will be conducted.

  9. Electrodeposition of magnesium and magnesium/aluminum alloys

    DOEpatents

    Mayer, A.

    1988-01-21

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

  10. Electrodeposition of magnesium and magnesium/aluminum alloys

    DOEpatents

    Mayer, Anton

    1988-01-01

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

  11. Luminescence properties of cerium-doped di-strontium magnesium di-silicate phosphor by the solid-state reaction method

    NASA Astrophysics Data System (ADS)

    Prasad Sahu, Ishwar

    2016-05-01

    A series of Sr2MgSi2O7:xCe3+ (x = 1.0%, 2.0%, 3.0%, 4.0% and 5.0%) phosphors were synthesized by the solid-state reaction method. The phosphor with optimum thermoluminescence, photoluminescence and mechanoluminescence (ML) intensity was characterized by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier transform infrared techniques. The trapping parameters (i.e. activation energy, frequency factor and order of the kinetics) of each synthesized phosphor have been calculated using the peak shape method and the results have been discussed. Under ultraviolet excitation (325 nm), Sr2MgSi2O7:xCe3+ phosphors were composed of a broad band peaking at 385 nm, belonging to the broad emission band which emits violet-blue color. Commission International de I'Eclairage coordinates have been calculated for each sample and their overall emission is near violet-blue light. In order to investigate the suitability of the samples for industrial uses, color purity and color rendering index were calculated. An ML intensity of optimum [Sr2MgSi2O7:Ce3+ (3.0%)] phosphor increases linearly with increasing impact velocity of the moving piston which suggests that these phosphors can be used as fracto-ML-based devices. The time of the peak ML intensity and the decay rate did not change significantly with respect to increasing impact velocity of the moving piston.

  12. Magnesium and metabolic syndrome: The role of magnesium in health and disease

    USDA-ARS?s Scientific Manuscript database

    Metabolic syndrome is a constellation of conditions associated with elevated risk of diabetes and cardiovascular disease. Magnesium, the fourth most abundant cation in the human body and required in over 300 enzymatic reactions, has been shown in experimental, observational, and clinical studies to ...

  13. Double-oxygen-atom transfer in reactions of Ce(m)O(2m)(+) (m=2-6) with C2H2.

    PubMed

    Ding, Xun-Lei; Wu, Xiao-Nan; Zhao, Yan-Xia; Ma, Jia-Bi; He, Sheng-Gui

    2011-08-01

    Cerium oxide cluster cations (Ce(m)O(n)(+), m=2-16; n=2m, 2m ± 1 and 2m ± 2) are prepared by laser ablation and reacted with acetylene (C(2)H(2)) in a fast-flow reactor. A time-of-flight mass spectrometer is used to detect the cluster distribution before and after the reactions. Reactions of stoichiometric Ce(m)O(2m)(+) (m=2-6) with C(2)H(2) produce Ce(m)O(2m-2)(+) clusters, which indicates a "double-oxygen-atom transfer" reaction Ce(m)O(2m)(+) + C(2)H(2) → Ce(m)O(2m-2)(+) + (CHO)(2) (ethanedial). A single-oxygen-atom transfer reaction channel is also identified as Ce(m)O(2m)(+) + C(2)H(2) → Ce(m)O(2m-1)(+) + C(2)H(2)O (at least for m=2 and 3). Density functional theory calculations are performed to study reaction mechanisms of Ce(2)O(4)(+) + C(2)H(2), and the calculated results confirm that both the single- and double-oxygen-atom transfer channels are thermodynamically and kinetically favourable. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2010 CFR

    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 (MgHPO4·3H2O...

  15. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic (MgHPO4·3H2O, CAS Reg. No. 7782-0975...

  16. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic...

  17. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic...

  18. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic...

  19. PIGE analysis of magnesium and beryllium

    NASA Astrophysics Data System (ADS)

    Fonseca, M.; Jesus, A. P.; Luís, H.; Mateus, R.; Cruz, J.; Gasques, L.; Galaviz, D.; Ribeiro, J. P.

    2010-06-01

    In this work, we present an alternative method for PIGE analysis of magnesium and beryllium in thick samples. This method is based on the ERYA - Emitted Radiation Yield Analysis - code, which integrates the nuclear reaction excitation function along the depth of the sample. For this purpose, the excitations functions of the 25Mg(p,p'γ) 25Mg ( Eγ = 585 keV) and 9Be(p,γ) 10B ( Eγ = 718 keV) reactions were employed. Calculated gamma-ray yields were compared, at several proton energy values, with experimental yields for thick samples made of inorganic compounds containing magnesium or beryllium. The agreement is better than 5%. Taking into consideration the experimental uncertainty of the measured yields and the errors related to the stopping power values, this agreement shows that effects as the beam energy straggling, ignored in the calculation, seem to play a minor role.

  20. Oxygenation Chemistry of Magnesium Alkyls Incorporating β-Diketiminate Ligands Revisited.

    PubMed

    Pietrzak, Tomasz; Kubisiak, Marcin; Justyniak, Iwona; Zelga, Karolina; Bojarski, Emil; Tratkiewicz, Ewa; Ochal, Zbigniew; Lewiński, Janusz

    2016-12-05

    Despite the fact that extensive research has been carried out, the oxygenation of alkyl magnesium species still remains a highly unexplored research area and significant uncertainties concerning the mechanism of these reactions and the composition of the resulting products persist. This case study compares the viability of the controlled oxygenation of alkylmagnesium complexes supported by β-diketiminates. The structural tracking of the reactivity of (N,N)MgR-type complexes towards O2 at low temperature showed that their oxygenation led exclusively to the formation of magnesium alkylperoxides (N,N)MgOOR. The results also highlight significant differences in the stability of the resulting alkylperoxides in solution and demonstrate that [(BDI)Mg(μ-η(2) :η(1) -OOBn)]2 (in which BDI=[(ArNCMe)2 CH](-) and Ar=C6 H3 iPr2 -2,6) can be easily transformed to the corresponding magnesium alkoxide [(BDI)MgOBn]2 at ambient temperature, whilst [((F3) BDI)Mg(μ-OOtBu)]2 (in which (F3) BDI=[(ArNCMe)2 CH](-) and Ar=C6 H2 F3 -2,4,6) is stable under similar conditions. The observed selective oxygenation of (N,N)MgR-type complexes to the corresponding (N,N)MgOOR alkylperoxides strongly contradicts the widely accepted radical-chain mechanism for the oxygenation of the main-group-metal alkyls. Furthermore, either the observed transformation of the alkylperoxide [(BDI)MgOOBn]2 to the alkoxide [(BDI)MgOBn]2 as well as the formation of an intractable mixture of products in the control reaction between the alkylperoxide [((F3) BDI)MgOOtBu]2 and the parent alkylmagnesium [((F3) BDI)MgtBu] complex are not in line with the common wisdom that magnesium alkoxide complexes' formation results from the metathesis reaction between MgOOR and Mg-R species. In addition, a high catalytic activity of well-defined magnesium alkylperoxides, in combination with tert-butyl hydroperoxide (TBHP) as an oxygen source, in the epoxidation of trans-chalcone is presented.

  1. Magnesium hydroxide extracted from a magnesium-rich mineral for CO{sub 2} sequestration in a gas-solid system

    SciTech Connect

    Pao-Chung Lin; Cheng-Wei Huang; Ching-Ta Hsiao; Hsisheng Teng

    2008-04-15

    Magnesium hydroxide extracted from magnesium-bearing minerals is considered a promising agent for binding CO{sub 2} as a carbonate mineral in a gas-solid reaction. An efficient extraction route consisting of hydrothermal treatment on serpentine in HCl followed by NaOH titration for Mg(OH){sub 2} precipitation was demonstrated. The extracted Mg(OH){sub 2} powder had a mean crystal domain size as small as 12 nm and an apparent surface area of 54 m{sup 2}/g. Under one atmosphere of 10 vol% CO{sub 2}/N{sub 2}, carbonation of the serpentine-derived Mg(OH){sub 2} to 26% of the stoichiometric limit was achieved at 325{sup o}C in 2 h; while carbonation of a commercially available Mg(OH){sub 2}, with a mean crystal domain size of 33 nm and an apparent surface area of 3.5 m{sup 2}/g, reached only 9% of the stoichiometric limit. The amount of CO{sub 2} fixation was found to be inversely proportional to the crystal domain size of the Mg(OH){sub 2} specimens. The experimental data strongly suggested that only a monolayer of carbonates was formed on the crystal domain boundary in the gas-solid reaction, with little penetration of the carbonates into the crystal domain. 24 refs., 6 figs., 2 tabs.

  2. Corrosion in Magnesium and a Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Akavipat, Sanay

    Magnesium and a magnesium alloy (AZ91C) have been ion implanted over a range of ions energies (50 to 150 keV) and doses (1 x 10('16) to 2 x 10('17) ions/cm('2)) to modify the corrosion properties of the metals. The corrosion tests were done by anodic polarization in chloride -free and chloride-containing aqueous solutions of a borated -boric acid with a pH of 9.3. Anodic polarization measurements showed that some implantations could greatly reduce the corrosion current densities at all impressed voltages and also increased slightly the pitting potential, which indicated the onset of the chloride attack. These improvements in corrosion resistance were caused by boron implantations into both types of samples. However, iron implantations were found to improve only the magnesium alloy. To study the corrosion in more detail, Scanning Auger Microprobe Spectrometer (SAM), Scanning Electron Microscope (SEM) with an X-ray Energy Spectrometry (XES) attachment, and Transmission Electron Microscope (TEM) measurements were used to analyze samples before, after, and at various corrosion stages. In both the unimplanted pure magnesium and AZ91C samples, anodic polarization results revealed that there were three active corrosion stages (Stages A, C, and E) and two passivating stages (Stages B and D). Examination of Stages A and B in both types of samples showed that only a mild, generalized corrosion had occurred. In Stage C of the TD samples, a pitting breakdown in the initial oxide film was observed. In Stage C of the AZ91C samples, galvanic and intergranular attack around the Mg(,17)Al(,12) intermetallic islands and along the matrix grain boundaries was observed. Stage D of both samples showed the formation of a thick, passivating oxygen containing, probably Mg(OH)(,2) film. In Stage E, this film was broken down by pits, which formed due to the presence of the chloride ions in both types of samples. Stages A through D of the unimplanted samples were not seen in the boron or iron

  3. A Quick Reference on Magnesium.

    PubMed

    Bateman, Shane W

    2017-03-01

    This article serves as a quick reference on the distribution, handling, and supplementation of magnesium. It also lists the manifestations and causes of magnesium deficit and provides criteria for the diagnosis of a magnesium deficit. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Magnesium Metabolism and its Disorders

    PubMed Central

    Swaminathan, R

    2003-01-01

    Magnesium is the fourth most abundant cation in the body and plays an important physiological role in many of its functions. Magnesium balance is maintained by renal regulation of magnesium reabsorption. The exact mechanism of the renal regulation is not fully understood. Magnesium deficiency is a common problem in hospital patients, with a prevalence of about 10%. There are no readily available and easy methods to assess magnesium status. Serum magnesium and the magnesium tolerance test are the most widely used. Measurement of ionised magnesium may become more widely available with the availability of ion selective electrodes. Magnesium deficiency and hypomagnesaemia can result from a variety of causes including gastrointestinal and renal losses. Magnesium deficiency can cause a wide variety of features including hypocalcaemia, hypokalaemia and cardiac and neurological manifestations. Chronic low magnesium state has been associated with a number of chronic diseases including diabetes, hypertension, coronary heart disease, and osteoporosis. The use of magnesium as a therapeutic agent in asthma, myocardial infarction, and pre-eclampsia is also discussed. Hypermagnesaemia is less frequent than hypomagnesaemia and results from failure of excretion or increased intake. Hypermagnesaemia can lead to hypotension and other cardiovascular effects as well as neuromuscular manifestations. Causes and management of hypermagnesaemia are discussed. PMID:18568054

  5. [Magnesium and the oxidative stress].

    PubMed

    Spasov, A A; Zheltova, A A; Kharitonov, M V

    2012-07-01

    Magnesium deficiency has been shown to result in alterations of cellular functions and biological activity of molecules. The review discusses possible relationship between Mg2+ deficiency and development of oxidative stress. Decrease of Mg2+ concentration in tissues and blood is accompanied with elevation of the oxidative stress markers, including products of the oxidative modification of lipids, proteins and DNA. The reduction in antioxidant defenses is synchronous with oxidative stress markers elevation. Different mechanisms including systemic reactions (hyperactivation of inflammation and endothelial dysfunction) and cellular changes (mitochondrial dysfunction and excessive production of fatty acids) are supposed to be involved in development and maintenance of the oxidative stress due to Mg2+ deficiency. Therefore the facts consolidated into the review evidence clear relation between Mg2+ deficiency and the oxidative stress development.

  6. Combined iron and magnesium isotope geochemistry of pyroxenite xenoliths from Hannuoba, North China Craton: implications for mantle metasomatism

    NASA Astrophysics Data System (ADS)

    Zhao, Xin Miao; Cao, Hui Hui; Mi, Xue; Evans, Noreen J.; Qi, Yu Han; Huang, Fang; Zhang, Hong Fu

    2017-06-01

    We present high-precision iron and magnesium isotopic data for diverse mantle pyroxenite xenoliths collected from Hannuoba, North China Craton and provide the first combined iron and magnesium isotopic study of such rocks. Compositionally, these xenoliths range from Cr-diopside pyroxenites and Al-augite pyroxenites to garnet-bearing pyroxenites and are taken as physical evidence for different episodes of melt injection. Our results show that both Cr-diopside pyroxenites and Al-augite pyroxenites of cumulate origin display narrow ranges in iron and magnesium isotopic compositions (δ57Fe = -0.01 to 0.09 with an average of 0.03 ± 0.08 (2SD, n = 6); δ26Mg = - 0.28 to -0.25 with an average of -0.26 ± 0.03 (2SD, n = 3), respectively). These values are identical to those in the normal upper mantle and show equilibrium inter-mineral iron and magnesium isotope fractionation between coexisting mantle minerals. In contrast, the garnet-bearing pyroxenites, which are products of reactions between peridotites and silicate melts from an ancient subducted oceanic slab, exhibit larger iron isotopic variations, with δ57Fe ranging from 0.12 to 0.30. The δ57Fe values of minerals in these garnet-bearing pyroxenites also vary widely (-0.25 to 0.08 in olivines, -0.04 to 0.25 in orthopyroxenes, -0.07 to 0.31 in clinopyroxenes, 0.07 to 0.48 in spinels and 0.31-0.42 in garnets). In addition, the garnet-bearing pyroxenite shows light δ26Mg (-0.43) relative to the mantle. The δ26Mg of minerals in the garnet-bearing pyroxenite range from -0.35 for olivine and orthopyroxene, to -0.34 for clinopyroxene, 0.04 for spinel and -0.68 for garnet. These measured values stand in marked contrast to calculated equilibrium iron and magnesium isotope fractionation between coexisting mantle minerals at mantle temperatures derived from theory, indicating disequilibrium isotope fractionation. Notably, one phlogopite clinopyroxenite with an apparent later metasomatic overprint has the heaviest δ57Fe

  7. Chemistry and photochemistry of 2,6-bis(2-hydroxybenzilidene)cyclohexanone. An example of a compound following the anthocyanins network of chemical reactions.

    PubMed

    Moro, Artur J; Pana, Ana-Maria; Cseh, Liliana; Costisor, Otilia; Parola, Jorge; Cunha-Silva, L; Puttreddy, Rakesh; Rissanen, Kari; Pina, Fernando

    2014-08-14

    The kinetics and thermodynamics of the 2,6-bis(2-hydroxybenzilidene)cyclohexanone chemical reactions network was studied at different pH values using NMR, UV-vis, continuous irradiation, and flash photolysis. The chemical behavior of the system partially resembles anthocyanins and their analogue compounds. 2,6-Bis(2-hydroxybenzilidene)cyclohexanone exhibits a slow color change from yellow to red styrylflavylium under extreme acidic conditions. The rate constant for this process (5 × 10(-5) s(-1)) is pH independent and controlled by the cis-trans isomerization barrier. However, the interesting feature is the appearance of the colorless compound, 7,8-dihydro-6H-chromeno[3,2-d]xanthene, isolated from solutions of acid to neutral range, characterized by (1)H NMR and single crystal X-ray diffraction. Light absorption by 2,6-bis(2-hydroxybenzilidene)cyclohexanone solutions immediately after preparation exclusively results in cis-isomer as photoproduct, which via hemiketal formation yields (i) red styrylflavylium by dehydration under extremely acidic solutions (pH < 1) and (ii) colorless 7,8-dihydro-6H-chromeno[3,2-d]xanthene by cyclization in solutions of acid to neutral range.

  8. Research of magnesium phosphosilicate cement

    NASA Astrophysics Data System (ADS)

    Ding, Zhu

    Magnesium phosphosilicate cement (MPSC) is a novel phosphate bonded cement, which consists mainly of magnesia, phosphate and silicate minerals. The traditional magnesium phosphate cements (MPCs) usually composed by ammonium phosphate, and gaseous ammonia will emit during mixing and in service. There is no noxious ammonia released from MPSC, furthermore, it can recycle a large volume of the non-hazardous waste. The goal of this research is to investigate the composition, reaction products, reaction mechanism, microstructure, properties, durability and applications of the MPSC. MPSC sets rapidly and has high early strength. It reacts better with solid industrial waste when compared to Portland cement. Many solid industrial wastes, such as fly ash, steel slag, coal gangue, red coal gangue, red mud, barium-bearing slag, copper slag, silica fume, and ground granulated blast furnace slag, have been used as the main component (40% by weight) in MPSC. The research has found that these aluminosilicate (or ironsilicate, or calciumsilicate) minerals with an amorphous or glass structure can enhance the performance of MPSC. The disorganized internal structure of amorphous materials may make it possess higher reactivity compared to the crystalline phases. Chemical reaction between phosphate and these minerals may form an amorphous gel, which is favorable to the cementing. Borax, boric acid and sodium tripolyphosphate have been used as retardants in the MPSC system. It is found that boric acid has a higher retarding effect on the setting of cement, than borax does. However, sodium polyphosphate accelerates the reaction of MPSC. The hydration of MPSC is exothermic reaction. The heat evolution may prompt hydrates formation, and shorten the setting process. Modern materials characterization techniques, XRD, DSC, TG-DTA FTIR, XPS, MAS-NMR, SEM, TEM, MIP, etc. were used to analyze the phase composition, micro morphology, and microstructure of hardened MPSC. The main hydration product

  9. Effect of transdermal magnesium cream on serum and urinary magnesium levels in humans: A pilot study

    PubMed Central

    Tanner, Amy; Sullivan, Keith; McAuley, William; Plesset, Michael

    2017-01-01

    Background Oral magnesium supplementation is commonly used to support a low magnesium diet. This investigation set out to determine whether magnesium in a cream could be absorbed transdermally in humans to improve magnesium status. Methods and findings In this single blind, parallel designed pilot study, n = 25 participants (aged 34.3+/-14.8y, height 171.5+/-11cm, weight 75.9 +/-14 Kg) were randomly assigned to either a 56mg/day magnesium cream or placebo cream group for two weeks. Magnesium serum and 24hour urinary excretion were measured at baseline and at 14 days intervention. Food diaries were recorded for 8 days during this period. Mg test and placebo groups’ serum and urinary Mg did not differ at baseline. After the Mg2+ cream intervention there was a clinically relevant increase in serum magnesium (0.82 to 0.89 mmol/l,p = 0.29) that was not seen in the placebo group (0.77 to 0.79 mmol/L), but was only statistically significant (p = 0.02)) in a subgroup of non-athletes. Magnesium urinary excretion increased from baseline slightly in the Mg2+ group but with no statistical significance (p = 0.48). The Mg2+ group showed an 8.54% increase in serum Mg2+ and a 9.1% increase in urinary Mg2+ while these figures for the placebo group were smaller, i.e. +2.6% for serum Mg2+ and -32% for urinary Mg2+. In the placebo group, both serum and urine concentrations showed no statistically significant change after the application of the placebo cream. Conclusion No previous studies have looked at transdermal absorbency of Mg2+ in human subjects. In this pilot study, transdermal delivery of 56 mg Mg/day (a low dose compared with commercial transdermal Mg2+ products available) showed a larger percentage rise in both serum and urinary markers from pre to post intervention compared with subjects using the placebo cream, but statistical significance was achieved only for serum Mg2+ in a subgroup of non-athletes. Future studies should look at higher dosage of magnesium cream for

  10. Effect of transdermal magnesium cream on serum and urinary magnesium levels in humans: A pilot study.

    PubMed

    Kass, Lindsy; Rosanoff, Andrea; Tanner, Amy; Sullivan, Keith; McAuley, William; Plesset, Michael

    2017-01-01

    Oral magnesium supplementation is commonly used to support a low magnesium diet. This investigation set out to determine whether magnesium in a cream could be absorbed transdermally in humans to improve magnesium status. In this single blind, parallel designed pilot study, n = 25 participants (aged 34.3+/-14.8y, height 171.5+/-11cm, weight 75.9 +/-14 Kg) were randomly assigned to either a 56mg/day magnesium cream or placebo cream group for two weeks. Magnesium serum and 24hour urinary excretion were measured at baseline and at 14 days intervention. Food diaries were recorded for 8 days during this period. Mg test and placebo groups' serum and urinary Mg did not differ at baseline. After the Mg2+ cream intervention there was a clinically relevant increase in serum magnesium (0.82 to 0.89 mmol/l,p = 0.29) that was not seen in the placebo group (0.77 to 0.79 mmol/L), but was only statistically significant (p = 0.02)) in a subgroup of non-athletes. Magnesium urinary excretion increased from baseline slightly in the Mg2+ group but with no statistical significance (p = 0.48). The Mg2+ group showed an 8.54% increase in serum Mg2+ and a 9.1% increase in urinary Mg2+ while these figures for the placebo group were smaller, i.e. +2.6% for serum Mg2+ and -32% for urinary Mg2+. In the placebo group, both serum and urine concentrations showed no statistically significant change after the application of the placebo cream. No previous studies have looked at transdermal absorbency of Mg2+ in human subjects. In this pilot study, transdermal delivery of 56 mg Mg/day (a low dose compared with commercial transdermal Mg2+ products available) showed a larger percentage rise in both serum and urinary markers from pre to post intervention compared with subjects using the placebo cream, but statistical significance was achieved only for serum Mg2+ in a subgroup of non-athletes. Future studies should look at higher dosage of magnesium cream for longer durations. ISRCTN registry ID No. ISRTN

  11. Cytotoxic effect of galvanically coupled magnesium-titanium particles.

    PubMed

    Kim, Jua; Gilbert, Jeremy L

    2016-01-01

    Recent work has shown that reduction reactions at metallic biomaterial surfaces can induce significant killing of cells in proximity to the surface. To exploit this phenomenon for therapeutic purposes, for example, for cancer tumor killing or antibacterial effects (amongst other applications), magnesium metal particles, galvanically coupled to titanium by sputtering, have been evaluated for their cell-killing capability (i.e. cytotoxicity). Magnesium (Mg) particles large enough to prevent particle phagocytosis were investigated, so that only electrochemical reactions, and not particle toxicity per se, caused cytotoxic effects. Titanium (Ti) coated magnesium particles, as well as magnesium-only particles were introduced into MC3T3-E1 mouse pre-osteoblast cell cultures over a range of particle concentrations, and cells were observed to die in a dosage-dependent manner. Ti-coated magnesium particles killed more cells at lower particle concentration than magnesium alone (P<0.05), although the pH measured for magnesium and magnesium-titanium had no significant difference at similar particle concentrations. Complete cell killing occurred at 750μg/ml and 1500μg/ml for Mg-Ti and Mg, respectively. Thus, this work demonstrates that galvanically coupled Mg-Ti particles have a significant cell killing capability greater than Mg alone. In addition, when the pH associated with complete killing with particles was created using NaOH only (no particles), then the percentage of cells killed was significantly less (P<0.05). Together, these findings show that pH is not the sole factor associated with cell killing and that the electrochemical reactions, including the reduction reactions, play an important role. Reduction reactions on galvanically coupled Mg-Ti and Mg particles may generate reactive oxygen intermediates that are able to kill cells in close proximity to the particles and this approach may lead to potential therapies for infection and cancer. This paper demonstrates

  12. Magnesium Research and Technology Development

    SciTech Connect

    Nyberg, Eric A.; Joost, William; Smith, Mark T.

    2009-12-30

    The Magnesium Research and Technical Development (MR&TD) project supports efforts to increase using magnesium in automotive applications, including improving technology, lowering costs and increasing the knowledge needed to enable alloy and manufacturing process optimization. MR&TD supports the U.S. Department of Energy (DOE)/United States Automotive Materials Partnership (USAMP) Magnesium Front End Research and Development (MFERD) project in collaboration with China and Canada. The MR&TD projects also maintains the magnesium bibliographic database at magnesium.pnl.gov.

  13. Magnesium balance in adolescent females consuming a low- or high-calcium diet.

    PubMed

    Andon, M B; Ilich, J Z; Tzagournis, M A; Matkovic, V

    1996-06-01

    Increasing emphasis is being placed on optimizing calcium intake during growth as a way to enhance peak bone mass. Although some studies in adults have shown that high calcium intake may negatively affect magnesium utilization, few data are available regarding the interaction of calcium and magnesium in healthy children. The purpose of our study was to measure the effect of calcium intake on magnesium balance in 26 adolescent girls (mean age 11.3 y) during a 14-d period. Subjects ate a controlled basal diet containing 667 mg Ca and 176 mg Mg. In addition to the basal diet, subjects were randomly assigned in a double-blind fashion to consume 1000 mg elemental Ca/d as calcium citrate malate or a placebo. Magnesium use did not differ between the low-calcium and high-calcium groups as measured by absorption (50% compared with 55%), urinary excretion (70 compared with 74 mg/d), and fecal excretion (88 compared with 79 mg/d). Accordingly, magnesium balance was not different in subjects consuming 667 or 1667 mg Ca/d and averaged 21 mg Mg/d for the whole study group. Magnesium balance was significantly correlated with magnesium intake (r = 0.511, P = 0.008) and magnesium absorption (r = 0.723, P < 0.001). Prediction intervals from the regression of magnesium balance on intake indicated that the current recommended dietary allowance of magnesium would result in magnesium balance > or = 8.5 mg/d in 95% of the girls. This value appears consistent with long-term accretion rates needed to account for the expansion of the total-body magnesium pool during growth. In summary, our observations support the adequacy of the current recommended dietary allowance for magnesium and indicate that alterations in magnesium utilization should not be anticipated in adolescent females consuming a high-calcium diet.

  14. Grain Refinement of Magnesium

    NASA Astrophysics Data System (ADS)

    Lee, Y. C.; Dahle, A. K.; StJohn, D. H.

    Grain formation during solidification of magnesium and Mg-Al alloys has been studied with a focus on grain refinement mechanisms, solute and particle effects. The variation in grain size with increased aluminium content in hypoeutectic Mg-Al alloys showed a continuous decrease in grain size up to 5 wt% Al, and a stabilisation at higher Al contents (above 5 wt%). Strontium additions to both low- and high-aluminium content magnesium alloys showed that Sr had a significant grain refining effect in low-aluminium containing alloys. However, strontium had a negligible effect on grain size in the Mg-9Al alloy. Additions of Zr, Si, or Ca to pure magnesium produced significant grain refinement, probably because these elements have high growth restriction effects during solidification. An attempt was made to identify the grain refinement effect of particles added directly to the melt that are considered to be powerful nucleants in Al based alloys (TiC) and in Mg based alloys (AlN, Al4C3). Most of these particles produced grain refinement, probably because of enhanced nucleation due to the small lattice disregistry between their crystal structures and that of magnesium. However, it is not clear whether the grain refining mechanism of the effective particles was catalysis of primary crystal nucleation or simply restriction of crystal growth during solidification.

  15. Do diuretics cause magnesium deficiency?

    PubMed Central

    Davies, D L; Fraser, R

    1993-01-01

    1. Controlled trials, of which there are few, do not substantiate claims that diuretics play a role in causing magnesium deficiency. Consequently, the vast majority of patients taking conventional doses of thiazide diuretics (i.e. bendrofluazide 2.5 mg day-1 or equivalent) do not need magnesium supplements. On balance, potassium-sparing diuretics tend to increase serum and intracellular magnesium content; this should not be taken as evidence of prior magnesium deficiency. It remains theoretically possible that large doses of loop diuretics given more than once daily for long periods could induce negative magnesium balance and magnesium deficiency. However, it has been difficult to run appropriately controlled trials in conditions where such therapy is needed (i.e. heart failure) and until more reliable information becomes available no absolute recommendation can be made. 2. Methods for the measurement of intracellular free magnesium levels are now available and are more relevant to the assessment of magnesium deficiency than total intracellular magnesium content; the complex relationship between intracellular free and total magnesium content remains to be defined. Future work involving the effect of diuretics on intracellular free magnesium measurements should make every attempt to avoid the errors of trial design and multiple publication that litter current and past literature. PMID:8373706

  16. Synthesis of magnesium aluminate spinel by periclase and alumina chlorination

    SciTech Connect

    Orosco, Pablo; Barbosa, Lucía; Ruiz, María del Carmen

    2014-11-15

    Highlights: • Use of chlorination for the synthesis of magnesium aluminate spinel. • The reagents used were alumina, periclase and chlorine. • Isothermal and non-isothermal assays were performed in air and Cl{sub 2}–N{sub 2} flows. • The chlorination produced magnesium aluminate spinel at 700 °C. • Selectivity of the chlorination reaction to obtain spinel is very high. - Abstract: A pyrometallurgical route for the synthesis of magnesium aluminate spinel by thermal treatment of a mechanical mixture containing 29 wt% MgO (periclase) and 71 wt% Al{sub 2}O{sub 3} (alumina) in chlorine atmosphere was developed and the results were compared with those obtained by calcining the same mixture of oxides in air atmosphere. Isothermal and non-isothermal assays were performed in an experimental piece of equipment adapted to work in corrosive atmospheres. Both reagents and products were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD) and X-ray fluorescence (XRF). Thermal treatment in Cl{sub 2} atmosphere of the MgO–Al{sub 2}O{sub 3} mixture produces magnesium aluminate spinel at 700 °C, while in air, magnesium spinel is generated at 930 °C. The synthesis reaction of magnesium aluminate spinel was complete at 800 °C.

  17. Redox Reactions of Reduced Flavin Mononucleotide (FMN), Riboflavin (RBF), and Anthraquinone-2,6-disulfonate (AQDS) with Ferrihydrite and Lepidocrocite

    SciTech Connect

    Shi, Zhi; Zachara, John M.; Shi, Liang; Wang, Zheming; Moore, Dean A.; Kennedy, David W.; Fredrickson, Jim K.

    2012-09-17

    Flavins are secreted by the dissimilatory iron-reducing bacterium Shewanella and can function as endogenous electron transfer mediators (ETM). In order to assess the potential importance of flavins in Fe(III) bioreduction, we investigated the redox reaction kinetics of reduced flavins (FMNH2 and RBFH2) with ferrihydrite and lepidocrocite. The organic reductants rapidly reduced and dissolved ferrihydrite and lepidocrocite in the pH range 4-8. The rate constant k for 2-line ferrihydrite reductive dissolution by FMNH2 was 87.5 ± 3.5 M-1∙s-1 at pH 7.0 in batch reactors, and the k was similar for RBFH2. For lepidocrocite, the k was 500 ± 61 M-1∙s-1 for FMNH2, and 236 ± 22 M-1∙s-1 for RBFH2. The surface area normalized initial reaction rates (ra) were between 0.08 and 77 μmoles∙m-2∙s-1 for various conditions in stopped-flow experiments. Initial rates (ro) were first-order with respect to Fe(III) oxide concentration, and ra increased with decreasing pH. Poorly crystalline 2-line ferrihydrite yielded the highest ra, followed by more crystalline 6-line ferrihydrite, and crystalline lepidocrocite. Compared to a previous whole-cell study with Shewanella oneidensis strain MR-1, our findings suggest that ETM reduction by the Mtr pathway coupled to lactate oxidation are rate limiting, rather than heterogeneous electron transfer to the Fe(III) oxide.

  18. Abdominal obesity and gestational diabetes: the interactive role of magnesium.

    PubMed

    Mostafavi, Ebrahim; Nargesi, Arash Aghajani; Asbagh, Firoozeh Akbari; Ghazizadeh, Zaniar; Heidari, Behnam; Mirmiranpoor, Hossein; Esteghamati, Alireza; Vigneron, Claude; Nakhjavani, Manouchehr

    2015-12-01

    Magnesium is a cofactor for numerous metabolic enzymatic reactions. It is required for glucose utilization and insulin signaling. We compared plasma magnesium concentrations in pregnant women with and without abdominal obesity, and investigated the interactive roles of magnesium and obesity in the development of gestational diabetes mellitus (GDM). Pregnant women with and without abdominal obesity (n = 40 in each group) were followed during gestation. Oral glucose tolerance tests (OGTT) were performed at 24-28 weeks of pregnancy to diagnose GDM. Plasma glucose, insulin, triglycerides, high-sensitive C-reactive protein (hs-CRP), and malondialdehyde (MDA) were measured. The obesity-GDM relationship was investigated prospectively, and the magnesium-GDM relationship was analyzed on a cross-sectional basis. Sixteen patients in the obese group and one in the control developed GDM. There were no differences in plasma magnesium levels between obese and control groups (p-value = 0.14), but significant differences between diabetic and non-diabetic patients (p-value = 0.05). Fourteen out of 17 diabetic patients had magnesium concentrations below the median. Increases in insulin, homeostatic model for insulin resistance, triglycerides, hs-CRP, MDA and second-hour blood glucose were more pronounced in those with both abdominal obesity and low-normal magnesium concentrations. In the Poisson regression model, obesity (relative risk = 20.6, p-value = 0.002), low-normal magnesium level (relative risk = 4.2, p-value = 0.009), and their interaction (p-value<0.001) were significant. Abdominally obese patients with lower plasma magnesium are more likely to show abnormal OGTT results. Insulin resistance, inflammatory response and oxidative stress are exaggerated in these patients.

  19. Molecular basis of the fructose-2,6-bisphosphatase reaction of PFKFB3: Transition state and the C-terminal function

    SciTech Connect

    Cavalier, Michael C.; Kim, Song-Gun; Neau, David; Lee, Yong-Hwan

    2012-03-22

    The molecular basis of fructose-2,6-bisphosphatase (F-2,6-P{sub 2}ase) of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFKFB) was investigated using the crystal structures of the human inducible form (PFKFB3) in a phospho-enzyme intermediate state (PFKFB3-P {center_dot} F-6-P), in a transition state-analogous complex (PFKFB3 {center_dot} AlF{sub 4}), and in a complex with pyrophosphate (PFKFB3 {center_dot} PP{sub i}) at resolutions of 2.45, 2.2, and 2.3 {angstrom}, respectively. Trapping the PFKFB3-P {center_dot} F-6-P intermediate was achieved by flash cooling the crystal during the reaction, and the PFKFB3 {center_dot} AlF{sub 4} and PFKFB3 {center_dot} PP{sub i} complexes were obtained by soaking. The PFKFB3 {center_dot} AlF{sub 4} and PFKFB3 {center_dot} PP{sub i} complexes resulted in removing F-6-P from the catalytic pocket. With these structures, the structures of the Michaelis complex and the transition state were extrapolated. For both the PFKFB3-P formation and break down, the phosphoryl donor and the acceptor are located within {approx}5.1 {angstrom}, and the pivotal point 2-P is on the same line, suggesting an 'in-line' transfer with a direct inversion of phosphate configuration. The geometry suggests that NE2 of His253 undergoes a nucleophilic attack to form a covalent N-P bond, breaking the 2O-P bond in the substrate. The resulting high reactivity of the leaving group, 2O of F-6-P, is neutralized by a proton donated by Glu322. Negative charges on the equatorial oxygen of the transient bipyramidal phosphorane formed during the transfer are stabilized by Arg252, His387, and Asn259. The C-terminal domain (residues 440-446) was rearranged in PFKFB3 {center_dot} PP{sub i}, implying that this domain plays a critical role in binding of substrate to and release of product from the F-2,6-P{sub 2}ase catalytic pocket. These findings provide a new insight into the understanding of the phosphoryl transfer reaction.

  20. Novel, electrolyte solutions comprising fully inorganic salts with high anodic stability for rechargeable magnesium batteries.

    PubMed

    Doe, Robert E; Han, Ruoban; Hwang, Jaehee; Gmitter, Andrew J; Shterenberg, Ivgeni; Yoo, Hyun Deog; Pour, Nir; Aurbach, Doron

    2014-01-07

    Herein the first inorganic magnesium salt solution capable of highly reversible magnesium electrodeposition is presented. Synthesized by acid-base reaction of MgCl2 and Lewis acidic compounds such as AlCl3, this salt class demonstrates upwards of 99% Coulombic efficiency, deposition overpotential of <200 mV, and anodic stability of 3.1 V.

  1. Novel, electrolyte solutions comprising fully inorganic salts with high anodic stability for rechargeable magnesium batteries

    SciTech Connect

    Doe, RE; Han, R; Hwang, J; Gmitter, AJ; Shterenberg, I; Yoo, HD; Pour, N; Aurbach, D

    2014-01-01

    Herein the first inorganic magnesium salt solution capable of highly reversible magnesium electrodeposition is presented. Synthesized by acid-base reaction of MgCl2 and Lewis acidic compounds such as AlCl3, this salt class demonstrates upwards of 99% Coulombic efficiency, deposition overpotential of <200 mV, and anodic stability of 3.1 V.

  2. Relationship between renal function and serum magnesium concentration in elderly outpatients treated with magnesium oxide.

    PubMed

    Horibata, Ken; Tanoue, Akiko; Ito, Masaaki; Takemura, Yousuke

    2016-05-01

    We investigated the relationship between renal function and serum magnesium concentration in elderly patients treated with magnesium oxide (MgO) in an outpatient setting of an urban hospital in Japan. In the present study, 44 elderly outpatients (23 patients with constipation treated with daily oral MgO and 21 untreated patients in the control group) who visited Kameyama municipal medical center were enrolled. Variables were age, sex, weight, height, serum magnesium concentration, serum blood urea nitrogen level, serum creatinine level, use of other magnesium-containing supplements and symptoms associated with hypermagnesemia. We calculated the estimated glomerular filtration rate (eGFR) and classified patients based on eGFR category. Compared with the control group, the MgO group showed a significantly higher concentration of serum magnesium (median 2.2 mg/dL [interquartile range 2.1-2.3] vs 2.4 mg/dL [2.2-2.6], P < 0.001). Hypermagnesemia (>2.6 mg/dL) was noted only in the MgO group. However, symptoms associated with hypermagnesemia occurred in patients from both groups, with no significant difference between groups. In the MgO group, significant difference was seen in the median serum magnesium concentration between eGFR categories (P < 0.05). The category G4 (eGFR 15-29 mL/min/1.73 m(2) ) group had the highest serum magnesium concentration in the MgO group (3.0 mg/L [2.9-3.1]). Elderly patients treated with MgO have higher serum magnesium levels compared with the control group. MgO should be prescribed with caution in patients with low renal function as shown by a GFR category G3b or less (eGFR < 30 mL/min/1.73 m(2) ). Geriatr Gerontol Int 2016; 16: 600-605. © 2015 Japan Geriatrics Society.

  3. Nondestructive spot test method for magnesium and magnesium alloys

    NASA Technical Reports Server (NTRS)

    Wilson, M. L. (Inventor)

    1973-01-01

    A method for spot test identification of magnesium and various magnesium alloys commonly used in aerospace applications is described. The spot test identification involves color codes obtained when several drops of 3 M hydrochloric acid are placed on the surface to be tested. After approximately thirty seconds, two drops of this reacted acid is transferred to each of two depressions in a spot plate for additions of other chemicals with subsequent color changes indicating magnesium or its alloy.

  4. Highly Soluble Alkoxide Magnesium Salts for Rechargeable Magnesium Batteries

    SciTech Connect

    Liao, Chen; Guo, Bingkun; Jiang, Deen; Custelcean, Radu; Mahurin, Shannon Mark; Sun, Xiao-Guang; Dai, Sheng

    2014-01-01

    A unique class of air-stable and non-pyrophoric magnesium electrolytes has been developed based on alkoxide magnesium compounds. The crystals obtained from this class of electrolytes exhibit a unique structure of tri-magnesium cluster, [Mg3Cl3(OR)2(THF)6]+ [(THF)MgCl3] . High reversible capacities and good rate capabilities were obtained in Mg-Mo6S8 batteries using these new electrolytes at both 20 and 50 oC.

  5. Magnesium borohydride: from hydrogen storage to magnesium battery.

    PubMed

    Mohtadi, Rana; Matsui, Masaki; Arthur, Timothy S; Hwang, Son-Jong

    2012-09-24

    Beyond hydrogen storage: The first example of reversible magnesium deposition/stripping onto/from an inorganic salt was seen for a magnesium borohydride electrolyte. High coulombic efficiency of up to 94 % was achieved in dimethoxyethane solvent. This Mg(BH(4))(2) electrolyte was utilized in a rechargeable magnesium battery. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Magnesium fluoride recovery method

    DOEpatents

    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.

  7. The dynamics of the O(1D) + HCl --> OH + Cl reaction at a 0.26 eV collision energy: a comparison between theory and experiment.

    PubMed

    Bargueño, P; Jambrina, P G; Alvariño, J M; Hernández, M L; Aoiz, F J; Menéndez, M; Verdasco, E; González-Lezana, T

    2009-12-31

    The dynamics of the O((1)D) + HCl(v = 0, j = 0) --> Cl + OH reaction at a 0.26 eV collision energy has been investigated by means of a quasiclassical trajectory (QCT) and statistical quantum and quasiclassical methods. State-resolved cross sections and Cl atom velocity distributions have been calculated on two different potential energy surfaces (PESs): the H2 surface (Martinez et al. Phys. Chem. Chem. Phys. 2000, 2, 589) and the latest surface by Peterson, Bowman, and co-workers (PSB2) (J. Chem. Phys. 2000, 113, 6186). The comparison with recent experimental results reveals that the PSB2 PES manages to describe correctly differential cross sections and the velocity distributions of the departing Cl atom. The calculations on the H2 PES seem to overestimate the OH scattering in the forward direction and the fraction of Cl at high recoil velocities. Although the comparison of the corresponding angular distributions is not bad, significant deviations with a statistical description are found, thus ruling out a complex-forming mechanism as the dominant reaction pathway. However, for the ClO + H product channel, the QCT and statistical predictions are found to be in good agreement.

  8. Low brain magnesium in migraine

    SciTech Connect

    Ramadan, N.M.; Halvorson, H.; Vande-Linde, A.; Levine, S.R.; Helpern, J.A.; Welch, K.M.

    1989-10-01

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

  9. Serpentine ore microtextures occurring in the magnola magnesium process

    NASA Astrophysics Data System (ADS)

    Chen, T. T.; Dutrizac, J. E.; White, Carl

    2000-04-01

    Serpentine ore was leached at 95°C and 100°C in 7.0 M HCl media to study the reactions occurring in Noranda’s Magnola magnesium process. Magnesium leaches rapidly from the serpentine Mg3Si2O5(OH)4, and the silicon remains in-situ as an amorphous silica pseudomorph after the original serpentine particles. Negligible silica dissolution occurs, and silica gelation was never observed. The reaction interface extends over 300 400 µm; as a consequence, fine grinding does not significantly accelerate the rate of magnesium dissolution. Associated inclusions of brucite Mg(OH)2, awaruite Ni8Fe3, and magnetite Fe3O4 dissolve rapidly; whereas, chromite FeCr2O4 and a chromium-rich spinel (Cr,Fe,Al,Mg)3O4 remain largely unaffected.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Magnesium in Disease Prevention and Overall Health12

    PubMed Central

    Volpe, Stella Lucia

    2013-01-01

    Magnesium is the fourth most abundant mineral and the second most abundant intracellular divalent cation and has been recognized as a cofactor for >300 metabolic reactions in the body. Some of the processes in which magnesium is a cofactor include, but are not limited to, protein synthesis, cellular energy production and storage, reproduction, DNA and RNA synthesis, and stabilizing mitochondrial membranes. Magnesium also plays a critical role in nerve transmission, cardiac excitability, neuromuscular conduction, muscular contraction, vasomotor tone, blood pressure, and glucose and insulin metabolism. Because of magnesium’s many functions within the body, it plays a major role in disease prevention and overall health. Low levels of magnesium have been associated with a number of chronic diseases including migraine headaches, Alzheimer’s disease, cerebrovascular accident (stroke), hypertension, cardiovascular disease, and type 2 diabetes mellitus. Good food sources of magnesium include unrefined (whole) grains, spinach, nuts, legumes, and white potatoes (tubers). This review presents recent research in the areas of magnesium and chronic disease, with the goal of emphasizing magnesium’s role in disease prevention and overall health. PMID:23674807

  12. Production and Refining of Magnesium Metal from Turkey Originating Dolomite

    NASA Astrophysics Data System (ADS)

    Demiray, Yeliz; Yücel, Onuralp

    2012-06-01

    In this study crown magnesium produced from Turkish calcined dolomite by the Pigeon Process was refined and corrosion tests were applied. By using factsage thermodynamic program metalothermic reduction behavior of magnesium oxide and silicate formation structure during this reaction were investigated. After thermodynamic studies were completed, calcination of dolomite and it's metalothermic reduction at temperatures of 1473 K, 1523 K and within a vacuum (varied from 20 to 200 Pa) and refining of crown magnesium was studied. Different flux compositions consisting of MgCl2, KCl, CaCl2, MgO, CaF2, NaCl, and SiO2 with and without B2O3 additions were selected for the refining process. These tests were carried out at 963 K for 15, 30 and 45 minutes setting time. Considerable amount of iron was transferred into the sludge phase and its amount decreased from 0.08% to 0.027%. This refined magnesium was suitable for the production of various magnesium alloys. As a result of decreasing iron content, minimum corrosion rate of refined magnesium was obtained 2.35 g/m2/day. The results are compared with previous studies.

  13. Magnesium Content of the Core: an Experimental Study

    NASA Astrophysics Data System (ADS)

    Fiquet, G.; Badro, J.; Auzende, A.; Siebert, J.; Gregoryanz, E.; Guignot, N.

    2006-12-01

    There is still a considerable debate about which light element among sulfur, silicon, oxygen, carbon or hydrogen should be in the core [Poirier, Phys. Earth Planet. Int., 85, 319, 1994]. The nature and distribution of these elements is a standing problem of prime importance, since it controls the freezing point depression at the inner core boundary. In addition to these candidates, new elements have been recently proposed as iron alloying constituants for the core, such as magnesium [Dubrovinskaia et al., Phys. Rev. Lett., 95, 245502, 2005]. We present series of experiments carried out on hot-pressed samples of iron and periclase in a laser-heated diamond-anvil cell, combined with in situ X-ray diffraction analysis and ATEM examination of recovered samples. We show that even at megabar pressures the amount of magnesium released in iron from the equilibrium with magnesium oxide is marginal. This finding is at odds with the 10 at% of magnesium found by Dubrovinskaia et al. [2005] in an iron alloy made from the reaction between iron and a metallic magnesium foil. Our observations suggest that magnesium is unlikely to be an important light element in the Earth's core. In addition, we provide structural data for iron to 130 GPa in excess of 3000 K with reliable pressure and temperature measurements, which enable us to propose a new thermal equation of state for iron at megabar pressures.

  14. [Magnesium disorder in metabolic bone diseases].

    PubMed

    Ishii, Akira; Imanishi, Yasuo

    2012-08-01

    Magnesium is abundantly distributed among the body. The half of the magnesium exists in the bone. In addition, magnesium is the second most abundant intracellular cation in vertebrates and essential for maintaining physiological function of the cells. Epidemiologic studies have demonstrated that magnesium deficiency is a risk factor for osteoporosis. The mechanism of bone fragility caused by magnesium deficiency has been intensely studied using animal models of magnesium deficiency. Magnesium deficiency causes decreased osteoblastic function and increased number of osteoclasts. Magnesium deficiency also accelerates mineralization in bone. These observations suggest that disturbed bone metabolic turnover and mineralization causes bone fragility.

  15. Clumped-isotope thermometry of magnesium carbonates in ultramafic rocks

    NASA Astrophysics Data System (ADS)

    García del Real, Pablo; Maher, Kate; Kluge, Tobias; Bird, Dennis K.; Brown, Gordon E.; John, Cédric M.

    2016-11-01

    Magnesium carbonate minerals produced by reaction of H2O-CO2 with ultramafic rocks occur in a wide range of paragenetic and tectonic settings and can thus provide insights into a variety of geologic processes, including (1) deposition of ore-grade, massive-vein cryptocrystalline magnesite; (2) formation of hydrous magnesium carbonates in weathering environments; and (3) metamorphic carbonate alteration of ultramafic rocks. However, the application of traditional geochemical and isotopic methods to infer temperatures of mineralization, the nature of mineralizing fluids, and the mechanisms controlling the transformation of dissolved CO2 into magnesium carbonates in these settings is difficult because the fluids are usually not preserved. Clumped-isotope compositions of magnesium carbonates provide a means to determine primary mineralization or (re)equilibration temperature, which permits the reconstruction of geologic processes that govern magnesium carbonate formation. We first provide an evaluation of the acid fractionation correction for magnesium carbonates using synthetic magnesite and hydromagnesite, along with natural metamorphic magnesite and low-temperature hydromagnesite precipitated within a mine adit. We show that the acid fractionation correction for magnesium carbonates is virtually indistinguishable from other carbonate acid fractionation corrections given current mass spectrometer resolution and error. In addition, we employ carbonate clumped-isotope thermometry on natural magnesium carbonates from various geologic environments and tectonic settings. Cryptocrystalline magnesite vein deposits from California (Red Mountain magnesite mine), Austria (Kraubath locality), Turkey (Tutluca mine, Eskişehir district) and Iran (Derakht-Senjed deposit) exhibit broadly uniform Δ47 compositions that yield apparent clumped-isotope temperatures that average 23.7 ± 5.0 °C. Based on oxygen isotope thermometry, these clumped-isotope temperatures suggest

  16. Combustion Synthesis of Magnesium Aluminate

    SciTech Connect

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

    2011-10-20

    In the system MgO-Al{sub 2}O{sub 3}, three compounds MgAl{sub 2}O{sub 4}, MgAl{sub 6}O{sub 10}(also expressed as-Mg{sub 0.4}Al{sub 2.4}O{sub 4}) and MgAl{sub 26}O{sub 40} are well known. Importance of the first two is well established. Magnesium aluminate (MgAl{sub 2}O{sub 4}) spinel is a technologically important material due to its interesting thermal properties. The MgAl{sub 2}O{sub 4} ceramics also find application as humidity sensors. Apart from the luminescence studies, the interest in MgAl{sub 2}O{sub 4} 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 MgAl{sub 6}O{sub 10} 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 MgAl{sub 2}O{sub 4} and MgAl{sub 6}O{sub 10} were formed in a single step, while MgAl{sub 26}O{sub 40} was not formed by this procedure. Activation of MgAl{sub 6}O{sub 10} by rare earth ions like Ce{sup 3+}, Eu{sup 3+} and Tb{sup 3+} and ns{sup 2} ion Pb{sup 2+} could be achieved. Excitation bands for MgAl{sub 6}O{sub 10} are at slightly shorter wavelengths compared to those reported for MgAl{sub 2}O{sub 4}.

  17. Magnesium Hall Thruster

    NASA Technical Reports Server (NTRS)

    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.

  18. Magnesium reduction of uranium oxide

    SciTech Connect

    Elliott, G.R.B.

    1985-08-13

    A method and apparatus are provided for reducing uranium oxide with magnesium to form uranium metal. The reduction is carried out in a molten-salt solution of density greater than 3.4 grams per cubic centimeter, thereby allowing the uranium product to sink and the magnesium oxide byproduct to float, consequently allowing separation of product and byproduct.

  19. Electrolytes for magnesium electrochemical cells

    DOEpatents

    Burrell, Anthony K.; Sa, Niya; Proffit, Danielle Lee; Lipson, Albert; Liao, Chen; Vaughey, John T.; Ingram, Brian J.

    2017-07-04

    An electrochemical cell includes a high voltage cathode configured to operate at 1.5 volts or greater; an anode including Mg.sup.0; and an electrolyte including an ether solvent and a magnesium salt; wherein: a concentration of the magnesium salt in the ether is 1 M or greater.

  20. Final report on the safety assessment of aluminum silicate, calcium silicate, magnesium aluminum silicate, magnesium silicate, magnesium trisilicate, sodium magnesium silicate, zirconium silicate, attapulgite, bentonite, Fuller's earth, hectorite, kaolin, lithium magnesium silicate, lithium magnesium sodium silicate, montmorillonite, pyrophyllite, and zeolite.

    PubMed

    Elmore, Amy R

    2003-01-01

    irritation study. Magnesium Aluminum Silicate and Sodium Magnesium Silicate caused minimal eye irritation in a Draize eye irritation test. Bentonite caused severe iritis after injection into the anterior chamber of the eyes of rabbits and when injected intralamellarly, widespread corneal infiltrates and retrocorneal membranes were recorded. In a primary eye irritation study in rabbits, Hectorite was moderately irritating without washing and practically nonirritating to the eye with a washout. Rats tolerated a single dose of Zeolite A without any adverse reaction in the eye. Calcium Silicate had no discernible effect on nidation or on maternal or fetal survival in rabbits. Magnesium Aluminum Silicate had neither a teratogenic nor adverse effects on the mouse fetus. Female rats receiving a 20% Kaolin diet exhibited maternal anemia but no significant reduction in birth weight of the pups was recorded. Type A Zeolite produced no adverse effects on the dam, embryo, or fetus in either rats or rabbits at any dose level. Clinoptilolite had no effect on female rat reproductive performance. These ingredients were not genotoxic in the Ames bacterial test system. In primary hepatocyte cultures, the addition of Attapulgite had no significant unscheduled DNA synthesis. Attapulgite did cause significant increases in unscheduled DNA synthesis in rat pleural mesothelial cells, but no significant increase in sister chromosome exchanges were seen. Zeolite particles (<10 microm) produced statistically significant increase in the percentage of aberrant metaphases in human peripheral blood lymphocytes and cells collected by peritoneal lavage from exposed mice. Topical application of Magnesium Aluminum Silicate to human skin daily for 1 week produced no adverse effects. Occupational exposure to mineral dusts has been studied extensively. Fibrosis and pneumoconiosis have been documented in workers involved in the mining and processing of Aluminum Silicate, Calcium Silicate, Zirconium Silicate

  1. Innovative Vacuum Distillation for Magnesium Recycling

    NASA Astrophysics Data System (ADS)

    Zhu, Tianbai; Li, Naiyi; Mei, Xiaoming; Yu, Alfred; Shang, Shixiang

    Magnesium recycling now becomes a very important subject as magnesium consumption increases fast around the world. All commonly used magnesium die-casting alloys can be recycled and recovered to the primary metal quality. The recycled materials may be comprised of biscuits, sprues, runners, flash, overflows, dross, sludge, scrap parts, and old parts that are returned from service, An innovative magnesium recycle method, vacuum distillation, is developed and proved out to be able to recycle magnesium scraps, especially machining chips, oily magnesium, smelting sludge, dross or the mixture. With this process at a specific temperature and environment condition, magnesium in scraps can be gasified and then solidified to become crystal magnesium crown. This `recycled' magnesium crown is collected and used as the raw material of magnesium alloys. The experimental results show the vacuum distillation is a feasible and plausible method to recycle magnesium. Further, the cost analysis will be addressed in this paper.

  2. Study of the e+e-→K+K- reaction in the energy range from 2.6 to 8.0 GeV

    NASA Astrophysics Data System (ADS)

    Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Brown, D. N.; Kerth, L. T.; Kolomensky, Yu. G.; Lee, M. J.; Lynch, G.; Koch, H.; Schroeder, T.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; So, R. Y.; Khan, A.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Kravchenko, E. A.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Lankford, A. J.; Dey, B.; Gary, J. W.; Long, O.; Franco Sevilla, M.; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; West, C. A.; Eisner, A. M.; Lockman, W. S.; Panduro Vazquez, W.; Schumm, B. A.; Seiden, A.; Chao, D. S.; Cheng, C. H.; Echenard, B.; Flood, K. T.; Hitlin, D. G.; Kim, J.; Miyashita, T. S.; Ongmongkolkul, P.; Porter, F. C.; Röhrken, M.; Andreassen, R.; Huard, Z.; Meadows, B. T.; Pushpawela, B. G.; Sokoloff, M. D.; Sun, L.; Ford, W. T.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Spaan, B.; Bernard, D.; Verderi, M.; Playfer, S.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cibinetto, G.; Fioravanti, E.; Garzia, I.; Luppi, E.; Piemontese, L.; Santoro, V.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Martellotti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Zallo, A.; Contri, R.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Bhuyan, B.; Prasad, V.; Adametz, A.; Uwer, U.; Lacker, H. M.; Mallik, U.; Chen, C.; Cochran, J.; Prell, S.; Ahmed, H.; Gritsan, A. V.; Arnaud, N.; Davier, M.; Derkach, D.; Grosdidier, G.; Le Diberder, F.; Lutz, A. M.; Malaescu, B.; Roudeau, P.; Stocchi, A.; Wormser, G.; Lange, D. J.; Wright, D. M.; Coleman, J. P.; Fry, J. R.; Gabathuler, E.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; di Lodovico, F.; Sacco, R.; Cowan, G.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Griessinger, K.; Hafner, A.; Schubert, K. R.; Barlow, R. J.; Lafferty, G. D.; Cenci, R.; Hamilton, B.; Jawahery, A.; Roberts, D. A.; Cowan, R.; Cheaib, R.; Patel, P. M.; Robertson, S. H.; Neri, N.; Palombo, F.; Cremaldi, L.; Godang, R.; Summers, D. J.; Simard, M.; Taras, P.; de Nardo, G.; Onorato, G.; Sciacca, C.; Raven, G.; Jessop, C. P.; Losecco, J. M.; Honscheid, K.; Kass, R.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simi, G.; Simonetto, F.; Stroili, R.; Akar, S.; Ben-Haim, E.; Bomben, M.; Bonneaud, G. R.; Briand, H.; Calderini, G.; Chauveau, J.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Biasini, M.; Manoni, E.; Rossi, A.; Angelini, C.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Chrzaszcz, M.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Oberhof, B.; Paoloni, E.; Rama, M.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Olsen, J.; Smith, A. J. S.; Anulli, F.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Pilloni, A.; Piredda, G.; Bünger, C.; Dittrich, S.; Grünberg, O.; Hess, M.; Leddig, T.; Voß, C.; Waldi, R.; Adye, T.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Vasseur, G.; Aston, D.; Bard, D. J.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dubois-Felsmann, G. P.; Ebert, M.; Field, R. C.; Fulsom, B. G.; Graham, M. T.; Hast, C.; Innes, W. R.; Kim, P.; Leith, D. W. G. S.; Luitz, S.; Luth, V.; Macfarlane, D. B.; Muller, D. R.; Neal, H.; Pulliam, T.; Ratcliff, B. N.; Roodman, A.; Schindler, R. H.; Snyder, A.; Su, D.; Sullivan, M. K.; Va'Vra, J.; Wisniewski, W. J.; Wulsin, H. W.; Purohit, M. V.; Wilson, J. R.; Randle-Conde, A.; Sekula, S. J.; Bellis, M.; Burchat, P. R.; Puccio, E. M. T.; Alam, M. S.; Ernst, J. A.; Gorodeisky, R.; Guttman, N.; Peimer, D. R.; Soffer, A.; Spanier, S. M.; Ritchie, J. L.; Schwitters, R. F.; Izen, J. M.; Lou, X. C.; Bianchi, F.; de Mori, F.; Filippi, A.; Gamba, D.; Lanceri, L.; Vitale, L.; Martinez-Vidal, F.; Oyanguren, A.; Albert, J.; Banerjee, Sw.; Beaulieu, A.; Bernlochner, F. U.; Choi, H. H. F.; King, G. J.; Kowalewski, R.; Lewczuk, M. J.; Lueck, T.; Nugent, I. M.; Roney, J. M.; Sobie, R. J.; Tasneem, N.; Gershon, T. J.; Harrison, P. F.; Latham, T. E.; Band, H. R.; Dasu, S.; Pan, Y.; Prepost, R.; Wu, S. L.; Babar Collaboration

    2015-10-01

    The e+e-→K+K- cross section and charged-kaon electromagnetic form factor are measured in the e+e- center-of-mass energy range (E ) from 2.6 to 8.0 GeV using the initial-state radiation technique with an undetected photon. The study is performed using 469 fb-1 of data collected with the BABAR detector at the PEP-II2 e+e- collider at center-of-mass energies near 10.6 GeV. The form factor is found to decrease with energy faster than 1 /E2 and approaches the asymptotic QCD prediction. Production of the K+K- final state through the J /ψ and ψ (2 S ) intermediate states is observed. The results for the kaon form factor are used together with data from other experiments to perform a model-independent determination of the relative phases between electromagnetic (single-photon) and strong amplitudes in J /ψ and ψ (2 S )→K+K- decays. The values of the branching fractions measured in the reaction e+e-→K+K- are shifted relative to their true values due to interference between resonant and nonresonant amplitudes. The values of these shifts are determined to be about ±5 % for the J /ψ meson and ±15 % for the ψ (2 S ) meson.

  3. Preparation of plate-shape nano-magnesium hydroxide from asbestos tailings

    NASA Astrophysics Data System (ADS)

    Gao-xiang, Du; Shui-lin, Zheng

    2009-09-01

    To prepare magnesium hydroxide is one of the effective methods to the comprehensive utilization of asbestos tailings. Nano-scale magnesium hydroxide was prepared and mechanisms of in-situ surface modification were characterized in the paper. Process conditions of preparation of magnesium hydroxide from purified hydrochloric acid leachate of asbestos tailings were optimized and in-situ surface modification of the product was carried out. Results showed that optimum process conditions for preparing nano-scale magnesium hydroxide were as follows: initial concentration of Mg2+ in the leachate was 22.75g/L, precipitant was NaOH solution (mass concentration 20%), reaction temperature was 50°C, and reaction time was 5min. The diameter and thickness of the plate nano-scale magnesium hydroxide powder prepared under optimal conditions were about 100 nm and 10 nm, respectively. However, particle agglomeration was obvious, the particle size increased to micron-grade. Dispersity of the magnesium hydroxide powder could be elevated by in-situ modification by silane FR-693, titanate YB-502 and polyethylene glycol and optimum dosages were 1.5%, 1.5% and 0.75% of the mass of magnesium hydroxide, respectively. All of the modifiers adsorbed chemically on surfaces of magnesium hydroxide particles, among which Si-O-Mg bonds formed among silane FR-693 and the particle surfaces and Ti-O-Mg among titanate YB-502 and the surfaces.

  4. Ignition Temperature of Magnesium Powder and Pyrotechnic Composition

    NASA Astrophysics Data System (ADS)

    Zhu, Chen-Guang; Wang, Hai-Zhen; Min, Li

    2014-07-01

    Using potassium nitrate, strontium nitrate, and potassium perchlorate as the oxidizing agents, the ignition and combustion behaviors of magnesium powders with different specific surface area were studied. The ignition temperature (Te) was extrapolated using a differential thermal analyzer, and the pyrotechnic spontaneous reaction temperature (Ts) was inferred from the temperature curve by inflection point analysis. The results showed that Ts has much better reproducibility than the extrapolated Te in characterizing the ignition of the pyrotechnic formulations. Increasing the specific surface area of the magnesium powder resulted in decreased Ts of the pyrotechnics.

  5. Biological implications of magnesium salts at the molecular level.

    PubMed

    Theophanides, T

    1996-12-01

    The interaction of Mg2+ cations in biological systems is studied by using nucleic acid bases as the biological system. Magnesium salts, such as, MgCl2 6H2O, MgSO4. 7H2O and Mg(ClO4). XH2O have been employed in order to compare their complexation with cytosine and 1-methyl cytosine crystallize in water solutions. The reaction of the above magnesium salts with the two bases has been followed by attempting to crystallization the complexes formed at constant temperature and variable times of crystallization. The water solutions with the above reagents have also been followed by Fourier Transform infrared.

  6. Nebulized Magnesium Sulfate in Acute Bronchiolitis: A Randomized Controlled Trial.

    PubMed

    Modaresi, Mohammad Reza; Faghihinia, Jamal; Kelishadi, Roya; Reisi, Mohsen; Mirlohi, Shahrokh; Pajhang, Farhad; Sadeghian, Majid

    2015-09-01

    To assess the efficacy of nebulized magnesium sulfate as a bronchodilator in infants hospitalized with acute bronchiolitis. This three-center double masked randomized clinical trial comprised 120 children with moderate to severe bronchiolitis. They were randomly assigned into two groups: the first group was treated with nebulized magnesium sulfate (40 mg/kg) and nebulized epinephrine (0.1 ml/kg) and the second group (control) was treated with nebulized epinephrine (0.1 ml/kg). The primary outcome was the length of hospital stay. The use of oxygen, temperature, oxygen saturation (SPO2), pulse rate (PR), respiratory rate (RR) and respiratory distress assessment instrument (RDAI) score were measured in the beginning of the study and during hospitalization. The mean (SD) age of 120 infants was 5.1(± 2.6) mo and 60% were boys. The length of hospital stay was not different between the two groups (P > 0.01). Use of oxygen supplementation, SPO2 and vital signs were similar in the two groups. Improvement in RDAI score was significantly better in infants treated with nebulized magnesium sulfate than in the other group (P 0.01). Thus, in infants with acute bronchiolitis, the effect of nebulized magnesium sulfate is comparable to nebulized epinephrine. However nebulized magnesium sulfate can improve the clinical score so it may have additive effect to reduce symptoms during hospitalization.

  7. Synthesis of micromesoporous magnesium oxide cubes with nanograin structures in a supercritical carbon dioxide/ethanol solution.

    PubMed

    Kim, Kwang Deok; Kim, Young Do; Kim, Sang Woo

    2011-07-01

    Micromesoporous magnesium oxide architectures with cubic morphologies were prepared via the chemical reaction of magnesium hydroxide in a supercritical carbon dioxide (CO2)-ethanol system, and via the sequential thermal combustion of the reaction products. The morphological change to the cube shape from an irregular form was induced by the dehydoxylation-carbonation reaction of magnesium hydroxide with supercritical CO2 at a reaction temperature of 150 degrees C, which leads to the greatly improved carbonation efficiency of magnesium hydroxide to magnesium carbonate. The precursor cubes with 3-5 microm sizes were decarbonized and transformed into the nanocrystalline MgO phase with pore sizes of 1.3-6 nm after calcining at 600 degrees C. The micromesoporous cube with high surface area of 117.5 m2/g was obtained by the thermal decarbonation with phase transition from rhombohedral to cubic phase. As a result, nanograined magnesium oxide cubes with micromesoporous structures and high specific surface areas were formed by the carbonation reaction of the magnesium hydroxide with the supercritical CO2, and the subsequent thermal decomposition of the magnesium carbonate cubes.

  8. Synthesis of magnesium diboride by magnesium vapor infiltration process (MVIP)

    DOEpatents

    Serquis, Adriana C.; Zhu, Yuntian T.; Mueller, Frederick M.; Peterson, Dean E.; Liao, Xiao Zhou

    2003-01-01

    A process of preparing superconducting magnesium diboride powder by heating an admixture of solid magnesium and amorphous boron powder or pellet under an inert atmosphere in a Mg:B ratio of greater than about 0.6:1 at temperatures and for time sufficient to form said superconducting magnesium diboride. The process can further include exposure to residual oxygen at high synthesis temperatures followed by slow cooling. In the cooling process oxygen atoms dissolved into MgB.sub.2 segregated to form nanometer-sized coherent Mg(B,O) precipitates in the MgB.sub.2 matrix, which can act as flux pinning centers.

  9. Magnesium deficiency: What is our status

    USDA-ARS?s Scientific Manuscript database

    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...

  10. 21 CFR 184.1431 - Magnesium oxide.

    Code of Federal Regulations, 2010 CFR

    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 carbonate...

  11. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false 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 crystallization...

  12. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2010 CFR

    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 crystallization...

  13. 21 CFR 184.1426 - Magnesium chloride.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium chloride. 184.1426 Section 184.1426 Food... Specific Substances Affirmed as GRAS § 184.1426 Magnesium chloride. (a) Magnesium chloride (MgC12·6H2O, CAS... mineral bischofite. It is prepared by dissolving magnesium oxide, hydroxide, or carbonate in aqueous...

  14. 21 CFR 184.1431 - Magnesium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium oxide. 184.1431 Section 184.1431 Food... GRAS § 184.1431 Magnesium oxide. (a) Magnesium oxide (MgO, CAS Reg. No. 1309-48-4) occurs naturally as... a relatively dense white powder (heavy) by heating magnesium hydroxide or carbonate. Heating these...

  15. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide... is prepared as a white precipitate by the addition of sodium hydroxide to a water soluble magnesium...

  16. 21 CFR 184.1431 - Magnesium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium oxide. 184.1431 Section 184.1431 Food... Specific Substances Affirmed as GRAS § 184.1431 Magnesium oxide. (a) Magnesium oxide (MgO, CAS Reg. No... bulky white powder (light) or a relatively dense white powder (heavy) by heating magnesium hydroxide or...

  17. 21 CFR 184.1431 - Magnesium oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium oxide. 184.1431 Section 184.1431 Food... Specific Substances Affirmed as GRAS § 184.1431 Magnesium oxide. (a) Magnesium oxide (MgO, CAS Reg. No... bulky white powder (light) or a relatively dense white powder (heavy) by heating magnesium hydroxide or...

  18. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false 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 crystallization...

  19. 21 CFR 184.1426 - Magnesium chloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium chloride. 184.1426 Section 184.1426 Food... Specific Substances Affirmed as GRAS § 184.1426 Magnesium chloride. (a) Magnesium chloride (MgC12·6H2O, CAS... mineral bischofite. It is prepared by dissolving magnesium oxide, hydroxide, or carbonate in aqueous...

  20. 21 CFR 184.1426 - Magnesium chloride.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium chloride. 184.1426 Section 184.1426 Food... Specific Substances Affirmed as GRAS § 184.1426 Magnesium chloride. (a) Magnesium chloride (MgC12·6H2O, CAS... mineral bischofite. It is prepared by dissolving magnesium oxide, hydroxide, or carbonate in aqueous...

  1. 21 CFR 184.1426 - Magnesium chloride.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium chloride. 184.1426 Section 184.1426 Food... Specific Substances Affirmed as GRAS § 184.1426 Magnesium chloride. (a) Magnesium chloride (MgC12·6H2O, CAS... mineral bischofite. It is prepared by dissolving magnesium oxide, hydroxide, or carbonate in aqueous...

  2. 21 CFR 184.1431 - Magnesium oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium oxide. 184.1431 Section 184.1431 Food... Specific Substances Affirmed as GRAS § 184.1431 Magnesium oxide. (a) Magnesium oxide (MgO, CAS Reg. No... bulky white powder (light) or a relatively dense white powder (heavy) by heating magnesium hydroxide or...

  3. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide... is prepared as a white precipitate by the addition of sodium hydroxide to a water soluble magnesium...

  4. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false 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 crystallization...

  5. Mineral resource of the month: magnesium

    USGS Publications Warehouse

    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).

  6. Dietary magnesium and urolithiasis in growing calves.

    PubMed

    Kallfelz, F A; Ahmed, A S; Wallace, R J; Sasangka, B H; Warner, R G

    1987-01-01

    The effect of high levels of dietary magnesium (1.4%) alone or in combination with elevated calcium (1.8%) or phosphorus (1.6%) on growth and health of male calves was evaluated during a nine week feeding trial after weaning. Twenty calves were randomly divided into 4 feeding groups consisting of controls, high magnesium, high magnesium and calcium or high magnesium and phosphorus. Elevated dietary minerals caused decreased feed intake and growth rate. Blood urea nitrogen and serum creatinine levels were greatly elevated in calves fed high magnesium or magnesium and phosphorus and serum urea nitrogen was moderately elevated in calves fed high magnesium and calcium. These elevations suggested the occurrence of renal damage as a result of microcrystalline obstruction of renal tubules. Serum magnesium levels were three times normal in calves fed high magnesium or magnesium and phosphorus, but only twice normal in calves fed high magnesium and calcium. High dietary magnesium resulted in a significant depression in blood calcium level. This effect was somewhat overcome by additional dietary calcium Three calves fed the high magnesium diet and two calves fed the high magnesium and phosphorus diet developed urinary tract obstruction. The chemical composition of uroliths recovered from these calves was calcium apatite. Elevated dietary magnesium has been shown to be a cause of urolithiasis in growing male calves. Additional dietary calcium, but not phosphorus, appears to protect calves against urolithiasis induced by elevated dietary magnesium.

  7. Impact of amorphous precursor phases on magnesium isotope signatures of Mg-calcite

    NASA Astrophysics Data System (ADS)

    Mavromatis, Vasileios; Purgstaller, Bettina; Dietzel, Martin; Buhl, Dieter; Immenhauser, Adrian; Schott, Jacques

    2017-04-01

    Various marine calcifiers form exoskeletons via an amorphous calcium carbonate (ACC) precursor phase and magnesium plays an important role in the temporary stabilization of this metastable phase. Thus, the use of Mg isotope ratios of marine biogenic carbonates as a proxy to reconstruct past seawater chemistry calls for a detailed understanding of the mechanisms controlling Mg isotope signatures during the formation and transformation of ACC to the final crystalline carbonate mineral. For this purpose we have investigated the Mg isotope fractionation between (Ca,Mg)CO3 solids and aqueous fluids at 25 °C and pH = 8.3 during (i) the direct precipitation of crystalline Mg-calcite and (ii) the formation of Mg-rich ACC (Mg-ACC) and its transformation to Mg-calcite. The outcome documents that the small Mg isotope fractionation between Mg-ACC and reactive fluid (ΔMg26ACC-fluid = - 1.0 ± 0.1 ‰) is not preserved during the transformation of the ACCs into Mg-calcite. Following a pronounced isotopic shift accompanying the transformation of Mg-ACC into Mg-calcite, Δ26Mgcalcite-fluid progressively decreases with reaction progress from ∼ - 3.0 ‰ to - 3.6 ‰, reflecting both the approach of isotopic equilibrium and the increase of calcite Mg content (to near 20 mol % Mg). In contrast the crystalline Mg-calcite precipitated directly from the reacting fluid, i.e. lacking a discernable formation of an amorphous precursor, exhibits only small temporal variations in Δ26Mgcalcite-fluid which overall is affected by the precipitation kinetics. The values found in this study at the onset of Mg-ACC precipitation for Mg isotope fractionation between Mg-ACC and the fluid (ΔMg26ACC-fluid = - 1.0 ‰) and between Mg-ACC and Mg2+(aq) (Δ(aq) 26 Mg ACC-Mg2+ = + 2.0 ‰) are consistent with the formation of a hydrated Ca nanoporous solid accommodating Mg bicarbonate/carbonate species in combination with hydrated magnesium. This material crossed by percolating channels filled with the

  8. Magnesium and calcium sulfate stabilities and the water budget of Mars

    USGS Publications Warehouse

    Chou, I.-Ming; Seal, R.R.

    2007-01-01

    Magnesium sulfate probably plays a dominant role in the water cycle of Mars away from the polar ice caps through hydration and dehydration reactions. This prominence is due to its abundance, its occurrence in numerous hydration states, and its ability to hydrate and dehydrate rapidly. New experimental studies on the metastable reaction between hexahydrite (MgSO4??6H2O) and starkeyite (MgSO4-4H2O) as a function of temperature and relative humidity, supplemented by recent investigations of the stable reaction between epsomite (MgSO4??7H2O) and hexahydrite and by phase equilibrium calculations, suggest that the most important magnesium sulfate phases involved in the Martian water cycle are MgSO4??11 H2O, epsomite, starkeyite, and possibly kieserite (MgSO4??H2O). Hexahydrite is not predicted to be stable on the surface of Mars. During diurnal variations in temperature and relative humidity, 1 kg of MgSO4 can release or remove from the atmosphere 1.5 kg of H2O by cycling between kieserite and MgSO4??11 H2O. Despite subequal abundances of calcium sulfate, calcium sulfates are not likely to be important in the water cycle of the planet because of sluggish rates of hydration and dehydration and a more limited range of H2O concentrations per kilogram of CaSO4 (0.00 to 0.26 kg kg-1). Modern or recent erosion on Mars attributed to liquid water may be due to the dehydration Of MgSO4??11 H2O because of the inferred abundance and likelihood of occurrence of this phase and its limited stability relative to known variations in temperature and relative humidity.

  9. Magnesium and calcium sulfate stabilities and the water budget of Mars

    NASA Astrophysics Data System (ADS)

    Chou, I.-Ming; Seal, Robert R.

    2007-11-01

    Magnesium sulfate probably plays a dominant role in the water cycle of Mars away from the polar ice caps through hydration and dehydration reactions. This prominence is due to its abundance, its occurrence in numerous hydration states, and its ability to hydrate and dehydrate rapidly. New experimental studies on the metastable reaction between hexahydrite (MgSO4.6H2O) and starkeyite (MgSO4.4H2O) as a function of temperature and relative humidity, supplemented by recent investigations of the stable reaction between epsomite (MgSO4.7H2O) and hexahydrite and by phase equilibrium calculations, suggest that the most important magnesium sulfate phases involved in the Martian water cycle are MgSO4.11H2O, epsomite, starkeyite, and possibly kieserite (MgSO4.H2O). Hexahydrite is not predicted to be stable on the surface of Mars. During diurnal variations in temperature and relative humidity, 1 kg of MgSO4 can release or remove from the atmosphere 1.5 kg of H2O by cycling between kieserite and MgSO4.11H2O. Despite subequal abundances of calcium sulfate, calcium sulfates are not likely to be important in the water cycle of the planet because of sluggish rates of hydration and dehydration and a more limited range of H2O concentrations per kilogram of CaSO4 (0.00 to 0.26 kg kg-1). Modern or recent erosion on Mars attributed to liquid water may be due to the dehydration of MgSO4.11H2O because of the inferred abundance and likelihood of occurrence of this phase and its limited stability relative to known variations in temperature and relative humidity.

  10. Magnesium Research and Technology Development

    SciTech Connect

    Nyberg, Eric A.; Carpenter, Joseph A.; Sklad, Philip S.

    2007-05-17

    The primary objective of this project is to provide DOE with high quality and state of the art information on magnesium R&D within the U.S. and around the world. The purpose of this information enables DOE to make informed decisions on direction for future funding related to magnesium applications within the U.S. and international cooperative programs. A second key objective is to serve as the Projecct Technical Committee representative for the 3-country Magnesium Front End R&D Project.

  11. Confession of a Magnesium Battery.

    PubMed

    Bucur, Claudiu B; Gregory, Thomas; Oliver, Allen G; Muldoon, John

    2015-09-17

    Magnesium is an ideal metal anode that has nearly double the volumetric capacity of lithium metal with a very negative reduction potential of -2.37 vs SHE. A significant advantage of magnesium is the apparent lack of dendrite formation during charging, which overcomes major safety and performance challenges encountered with using lithium metal anodes. Here, we highlight major recent advances in nonaqueous Mg electrochemistry, notably the development of electrolytes and cathodes, and discuss some of the challenges that must be overcome to realize a practical magnesium battery.

  12. Nonlinear anelasticity of magnesium

    NASA Astrophysics Data System (ADS)

    Aning, Alexander; Suzuki, Tetsuro; Wuttig, Manfred

    1982-10-01

    An approximate solution of the equation of motion of a nonlinear anelastic reed at or near resonance is presented. The steady state solution reproduces the well-known nonlinear resonances. The solution also predicts the existence of automodulations, i.e., self-excited modulations of the amplitude and phase at constant power of excitation of the reed. Numerical examples of such automodulations are presented for an antisymmetric deformation potential. Experimental studies of finite amplitude oscillations of a magnesium reed vibrating at 72 and 431 Hz at room temperature confirm the existence of automodulations. The experimental results can be semiquantitatively described in terms of the solution given. The assumption that finite deformation by twinning represents the essential nonlinearity leads to a self-consistent interpretation. The relaxation time of twinning is obtained from the analysis of the automodulation and is 22 msec in the sample investigated. It is proposed that point defects control the relaxation process.

  13. Magnesium: Engineering the Surface

    NASA Astrophysics Data System (ADS)

    Chen, X. B.; Yang, H. Y.; Abbott, T. B.; Easton, M. A.; Birbilis, N.

    2012-06-01

    Magnesium (Mg) and its alloys provide numerous benefits as lightweight materials; however, industrial deployment of Mg in most instances requires anticorrosion coatings. Engineering the Mg surface is an area that has been undergoing intense research recently. Surface engineering commences with the "pretreatment" step, which can be used to modify the surface composition and morphology, resulting in surface enrichment or depletion of alloying elements. Following this, electrochemical plating (including electro- and electroless plating) and conversion coatings have emerged as common means of coating Mg. In this study, we present the key aspects relating to the science and technology associated with pretreatment, electrochemical plating, and conversion coatings. This is followed by experimental examples of engineered surfaces of industrial relevance.

  14. Solidification Characteristics of Wrought Magnesium Alloys Containing Rare Earth Metals

    NASA Astrophysics Data System (ADS)

    Javaid, A.; Czerwinski, F.; Zavadil, R.; Aniolek, M.; Hadadzadeh, A.

    A significant barrier preventing use of magnesium sheet in automotive light-weighting initiatives is its high manufacturing cost and very limited formability at room temperature. This barrier can be overcome by the use of twin roll casting technology and new magnesium alloys, specifically designed for twin roll casting. Recent studies have shown that magnesium, when alloyed with rare earth elements, gave rise to weakening of the basal texture resulting in improved room temperature formability. In this research, a combination of calculations using the FACTsage software and examinations using a number of experimental techniques was explored to determine the solidification characteristics of wrought magnesium alloys containing rare earth metal of neodymium: ZEK100, Mg-1Zn-0.5Nd and Mg-1Zn-1Nd. As predicted by the FACTsage software, the solidification under equilibrium and non-equilibrium conditions affects the type and volume fractions of phases formed for a given chemical composition of the alloy. The thermal analysis identified temperatures of metallurgical reactions taking place during solidification and their changes with neodymium content. As verified by controlled solidification experiments the cooling rate during solidification affected the refinement level of the alloy microstructure, a volume fraction of intermetallic precipitates and their distribution. This research will help to design new magnesium alloys, specifically optimized for twin roll casting.

  15. Stimulated and Unstimulated Saliva Levels of Calcium and Magnesium in Giardiasis.

    PubMed

    Shaddel, Minoo; Mirzaii-Dizgah, Iraj; Sharifi-Sarasiabi, Khojasteh; Kamali, Zahra; Dastgheib, Mani

    2017-01-22

    Giardia lamblia causes malabsorption. The aim of this study was to evaluate serum and saliva calcium and magnesium levels in patients with giardiasis. Thirty patients with giardiasis as a case and 30 person without giardiasis as a control group were enrolled. The stimulated and unstimulated whole saliva and serum calcium and magnesium levels were assayed by Arsenazo reaction and xylidyl blue complex methods, respectively. Mean calcium and magnesium level was low in serum and stimulated saliva of case group than that of controls. However, they were higher in the unstimulated saliva of the case group. It is suggested that patients suffering from giardiasis have low calcium and magnesium levels, and they lose the most of calcium and magnesium by saliva during unstimulated condition.

  16. In defense of magnesium sulfate.

    PubMed

    Elliott, John P; Lewis, David F; Morrison, John C; Garite, Thomas J

    2009-06-01

    Magnesium sulfate has been used by obstetricians for more than 25 years to treat preterm labor. Magnesium sulfate is effective in delaying delivery for at least 48 hours in patients with preterm labor when used in higher dosages. There do not seem to be any harmful effects of the drug on the fetus, and indeed there is a neuroprotective effect in reducing the incidence of cerebral palsy in premature newborns weighing less than 1,500 g.

  17. Producing titanium by reducing TiCl2-MgCl2 mixed salt with magnesium in the molten state

    NASA Astrophysics Data System (ADS)

    Fuwa, Akio; Takaya, Satoru

    2005-10-01

    In the Kroll process for titanium sponge metal production, TiCl4 gas is introduced and reacted with molten magnesium metal via a gas-liquid reduction reaction. The magnesium reduction reaction of the mixed salt of TiCl2-MgCl2 via a liquid-liquid reaction has been investigated and the results are reported in this article. First, the molten mixed salt was synthesized through chlorination reaction of solid titanium sponge placed in molten MgCl2 salt, while TiCl4 gas was bubbled at around 1,173K. Then, the TiCl2-MgCl2 was reacted with molten magnesium at similar temperatures. This proposed magnesium reduction reaction of the TiCl2-MgCl2 in the molten state may be more efficient, easier to control, and suitable for realizing continuous titanium production.

  18. Effect of magnesium sulfate concentration on serum ionized magnesium in vitro.

    PubMed

    Salamon, Mia; Mimouni, Francis B; Dollberg, Shaul; Mandel, Dror

    2010-08-01

    We undertook this in vitro study to quantify the effect that addition of magnesium (Mg) sulfate to neonatal serum, as compared with adult serum, might have on ionized Mg (Mg (2+)) concentration. We used one cord blood sample and one adult blood sample that we made hypermagnesemic by adding various amounts of magnesium sulfate to study five levels of serum Mg. Each sample was then studied at one of three levels of pH, from extreme alkalosis to extreme acidosis. We measured the changes in serum Mg (2+) and serum ionized calcium (Ca (2+)) in reaction to these changes in pH and Mg. At each pH level, there was an exponential increase in the serum Mg (2+) (and no significant change in serum Ca (2+)) with increasing serum Mg. Multiple regression analysis using Mg (2+) as the dependent variable and baseline Ca (2+), phosphorous, albumin, and blood type (adult versus cord blood) as well as blood pH and serum Mg as independent variables indicated that serum Mg and pH were the only variables significantly influencing serum Mg (2+). Within the range of serum Mg considered, the addition of magnesium sulfate in vitro causes an exponential increase in Mg (2+) and no significant change in serum Ca (2+). Copyright Thieme Medical Publishers.

  19. Liberation of hydrogen from gastric acid following administration of oral magnesium.

    PubMed

    Sack, D A; Stephensen, C B

    1985-12-01

    We are in the process of developing a noninvasive test for gastric acid secretion based on the reaction of orally administered magnesium metal with gastric acid: Mg + 2HCl in equilibrium with MgCl2 + H2. We hypothesized that the hydrogen gas thus evolved could be detected in exhaled air and belches and that the amount of hydrogen released could be related to the amount of acid in the stomach. To validate this hypothesis, we gave magnesium to two groups of young adult volunteers following either betazole stimulation or cimetidine inhibition of acid secretion. In group I we gave subcutaneous betazole and gave magnesium in doses from 10 to 200 mg. In group II we gave oral betazole and used a constant dose of 150 mg of magnesium. In both groups we consistently detected significant increases in breath and belch hydrogen following magnesium in the betazole-stimulated volunteers. This response was blocked by cimetidine. The magnitude of the response was related to the magnesium dose, with 150 mg appearing to induce a maximum response. Administration of oral magnesium up to 200 mg was not associated with any untoward effects. We conclude that magnesium led to the release of hydrogen gas in vivo and that the quantity of hydrogen gas recovered was related to the amount of gastric acid. With further development, this principle might be used to develop a simple noninvasive test for gastric acid secretion.

  20. Biodegradation of metallic magnesium elicits an inflammatory response in primary nasal epithelial cells.

    PubMed

    Schumacher, S; Roth, I; Stahl, J; Bäumer, W; Kietzmann, M

    2014-02-01

    Resorbable magnesium-based implants hold great promise for various biomedical applications, such as osteosynthesis and coronary stenting. They also offer a new therapeutic option for the treatment of chronic rhinosinusitis, but little data is yet available regarding the use of magnesium in the nasal cavity. To model this field of application, primary porcine nasal epithelial cells were used to test the biocompatibility of degrading pure magnesium and investigate whether the degradation products may also affect cellular metabolism. Magnesium specimens did not induce apoptosis and we found no major influence on enzyme activities or protein synthesis, but cell viability was reduced and elevated interleukin 8 secretion indicated proinflammatory reactions. Necrotic damage was most likely due to osmotic stress, and our results suggest that magnesium ion build-up is also involved in the interleukin 8 release. Furthermore, the latter seems to be mediated, at least in part, by the p38 signaling pathway. These effects probably depended on the accumulation of very high concentrations of magnesium ions in the in vitro set-up, which might not be achieved in vivo, although we cannot exclude that further, as yet unknown, factors played a role in the inflammatory response during the degradation process. In conclusion, the biocompatibility of pure magnesium with cells in the immediate vicinity appears less ideal than is often supposed, and this needs to be considered in the evaluation of magnesium materials containing additional alloying elements. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. The role of ammonium citrate washing on the characteristics of mechanochemical-hydrothermal derived magnesium-containing apatites.

    PubMed

    Chen, Chun-Wei; Suchanek, Wojciech L; Shuk, Pavel; Byrappa, Kullaiah; Oakes, Charles; Riman, Richard E; Brown, Kelly; Tenhuisen, Kevor S; Janas, Victor F

    2007-07-01

    The role of citrate washing on the physical and chemical characteristics of magnesium-substituted apatites (HAMgs) was performed. HAMgs were synthesized by a mechanochemical-hydrothermal route at room temperature in as little as 1 h, which is five times faster than our previous work. Magnesium-substituted apatites had concentrations as high as 17.6 wt% Mg with a corresponding specific surface area (SSA) of 216 m(2)/g. A systematic study was performed to examine the influence of increasing magnesium content on the physical and chemical characteristics of the reaction products. As the magnesium content increased from 0 to 17.6 wt%, magnesium-doped apatite crystallite size decreased from 12 to 8.8 nm. The Mg/(Mg + Ca) ratio in the product was enriched relative to that used for the reacting precursor solution. During mechanochemical-hydrothermal reaction, magnesium doped apatites co-crystallize with magnesium hydroxide. Citrate washing serves to remove the magnesium hydroxide phase. The concomitant increase in surface area results because of the removal of this phase. Possible mechanisms for magnesium hydroxide leaching are discussed to explain the measured trends.

  2. Magnesium and Dialysis: The Neglected Cation.

    PubMed

    Alhosaini, Mohamad; Leehey, David J

    2015-09-01

    Disorders of magnesium homeostasis are very common in dialysis patients but have received scant attention. In this review, we address measurement of plasma magnesium, magnesium balance and the factors that affect magnesium flux during dialysis, the prevalence of hypo- and hypermagnesemia in dialysis patients, and the potential clinical significance of hypo- and hypermagnesemia in dialysis patients. Many factors can affect plasma magnesium concentration, including diet, nutritional status (including plasma albumin level), medications (such as proton pump inhibitors), and dialysis prescription. Further interventional studies to determine the effect of normalization of plasma magnesium concentration on clinical outcomes are needed. At the present time, we recommend that predialysis plasma magnesium be measured on a regular basis, with the dialysate magnesium concentration adjusted to maintain plasma magnesium concentration within the normal range.

  3. Effect of inhaled magnesium sulfate on bronchial hyperresponsiveness.

    PubMed

    Wang, Hui; Xiong, Yi; Gong, Caihui; Yin, Lijuan; Yan, Li; Yuan, Xiaoping; Liu, Sha; Shi, Tiantian; Dai, Jihong

    2015-04-01

    To determine the response of nebulized magnesium sulfate on the lung function of children with bronchial hyperresponsiveness. Eighty-four children with asthma were divided into three groups randomly: magnesium sulfate (M), albuterol (A), and a combination of magnesium sulfate and albuterol (M + A). All patients were nebulized with acetylcholine, and then treated as designed. Lung function was compared between the three groups. Forced expiratory volume in first second (FEV1) significantly improved in all the three groups but it was better in (A) and (M + A) compared to (M) at 10 min and 20 min [10 min: 1.26 L ± 0.53 (A) vs. 1.10 L ± 0.27 (M), 1.35 L ± 0.59 (M + A) vs. 1.10 L ± 0.27 (M), p < 0.05; 20 min: 1.32 L ± 0.61 (A) vs. 1.17 L ± 0.30 (M), 1.42 L ± 0.59 (M + A) vs. 1.17 L ± 0.30 (M), p < 0.05]. Variation of FEV1, as absolute value at 10 min or 20 min over post-Ach FEV1 was significantly different in (A) or (M + A) compared to (M). Nebulized albuterol and magnesium sulfate + albuterol can more effectively improve FEV1 in children with bronchial hyperresponsiveness than nebulized magnesium sulfate at 10 min and 20 min after inhalation. It is further suggested that addition of magnesium sulfate to albuterol does not result in additional benefit.

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

    PubMed

    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.

  5. [Exploitation of the chemistry of magnesium carbenoids and their use in organic synthesis].

    PubMed

    Satoh, Tsuyoshi

    2009-09-01

    Synthetic organic chemistry is a base of medicinal chemistry and the exploitation of new methods for carbon-carbon bond formation is of most importance in synthetic organic chemistry. Carbenes and carbenoids have long been known to be highly reactive carbon species that show a variety of unique reactivity. However, those reactive species are not fully used in organic synthesis. The reasons are as follows: one is the precursors for the generation of carbenes and carbenoids are quite limited and the other is that the reactivity of the species is too high to control. In order to solve the problem mentioned above, we used alpha-haloalkyl (or alkenyl) aryl sulfoxides as the precursors and used sulfoxide-magnesium exchange reaction for generation of much mild magnesium carbenoids. alpha-Haloalkyl (or alkenyl) aryl sulfoxides are quite easily synthesized in high overall yields. Magnesium carbenoids, cyclopropylmagnesium carbenoids, cyclobutylmagnesium carbenoids, magnesium beta-oxido carbenoids, and magnesium alkylidene carbenoids are generated at low temperature from the corresponding sulfoxides with a Grignard reagent in quantitative yields. They were found to be stable usually at below -60 degrees C for at least 30 min. The each magnesium carbenoids have their own unique reactivities and we could find many unprecedented reactions from these reactive species. Recent results for the developments of new synthetic methods based on the chemistry of magnesium carbenoids are described.

  6. On the role of magnesium and silicon in the formation of alumina from aluminum alloys by means of DIMOX processing

    NASA Astrophysics Data System (ADS)

    Yang, Liu; Zhu, Degui; Xu, Changqing; Zhang, Jun; Zhang, Jian

    1996-08-01

    This article deals with the reaction mechanisms of the DIMOX (Directed Melt Oxided) processing of aluminum alloys. An orthogonalized experimental procedure was introduced to stipulate the effects of the reaction temperature, reaction time, and additional metallic elements, magnesium and silicon, on the oxidation process of aluminum alloys. Emphasis is placed on the distribution of magnesium and silicon in the products so that the behaviors of these two crucial elements for the formation of alumina from directed oxidation of aluminum alloys could be revealed. Alterative methods, including optical and scanning electron microscopy (SEM), electron probing, and wave spectrum analysis were applied to specify the microstructure characters of the products and locate the position of both magnesium and silicon in the reaction products. Judged by the weight gain after reaction, the results indicated that the temperature is the most influential factor in controlling the oxidation kinetics. Silicon is more effective than magnesium in accelerating the process, although magnesium is indispensable for the process to take place. While judged by the morphology of the reaction products, an excessive amount of silicon is harmful to the DIMOX process in that the final products consist of a large amount of porosity. Both magnesium and silicon are rather concentrated in specific regions than homogeneously distributed in the whole products. The contents of magnesium and silicon in the surface region are not as high as expected, with most of the magnesium being concentrated in the region directly neighboring the bulky metals and most of the Si in the residual bulky metals, although the contents of these two elements in the surface region are a little higher than the regions next to the surface. These characteristics, combined with other investigations, suggest that the decisive role of the slight amount of magnesium and silicon in the nucleation and growth of Al2O3 could be explained by

  7. The Grignard Reagent: Preparation, Structure, and Some Reactions.

    ERIC Educational Resources Information Center

    Orchin, Milton

    1989-01-01

    The Grignard reagent used in the laboratory synthesis of organic compounds is the product resulting from the reaction of an alkyl or aryl halide with elemental magnesium. Describes the structure, formation, and some reactions of the reagent. (YP)

  8. The Grignard Reagent: Preparation, Structure, and Some Reactions.

    ERIC Educational Resources Information Center

    Orchin, Milton

    1989-01-01

    The Grignard reagent used in the laboratory synthesis of organic compounds is the product resulting from the reaction of an alkyl or aryl halide with elemental magnesium. Describes the structure, formation, and some reactions of the reagent. (YP)

  9. Plasma and dietary magnesium and risk of sudden cardiac death in women123

    PubMed Central

    Chiuve, Stephanie E; Korngold, Ethan C; Januzzi, James L; Gantzer, Mary Lou; Albert, Christine M

    2011-01-01

    Background: Magnesium has antiarrhythmic properties in cellular and experimental models; however, its relation to sudden cardiac death (SCD) risk is unclear. Objective: We prospectively examined the association between magnesium, as measured in diet and plasma, and risk of SCD. Design: The analysis was conducted within the Nurses’ Health Study. The association for magnesium intake was examined prospectively in 88,375 women who were free of disease in 1980. Information on magnesium intake, other nutrients, and lifestyle factors was updated every 2–4 y through questionnaires, and 505 cases of sudden or arrhythmic death were documented over 26 y of follow-up. For plasma magnesium, a nested case-control analysis including 99 SCD cases and 291 controls matched for age, ethnicity, smoking, and presence of cardiovascular disease was performed. Results: After multivariable adjustment for confounders and potential intermediaries, the relative risk of SCD was significantly lower in women in the highest quartile compared with those in the lowest quartile of dietary (relative risk: 0.63; 95% CI: 0.44, 0.91) and plasma (relative risk: 0.23; 95% CI: 0.09, 0.60) magnesium. The linear inverse relation with SCD was strongest for plasma magnesium (P for trend = 0.003), in which each 0.25-mg/dL (1 SD) increment in plasma magnesium was associated with a 41% (95% CI: 15%, 58%) lower risk of SCD. Conclusions: In this prospective cohort of women, higher plasma concentrations and dietary magnesium intakes were associated with lower risks of SCD. If the observed association is causal, interventions directed at increasing dietary or plasma magnesium might lower the risk of SCD. PMID:21106914

  10. Magnesium Uptake by Soybeans

    PubMed Central

    Leggett, J. E.; Gilbert, W. A.

    1969-01-01

    Magnesium contents of soybean (Glycine max) roots increase and the K and Ca contents decrease with increased MgCl2 concentrations in ambient solutions. The Mg uptake is inhibited when both Ca and K are present in the solution, but not by K or Ca alone. Chloride uptake, which is very low from the MgCl2 solution, is greatly enhanced by the presence of K. The selectivity against Mg imparted by K + Ca appears to be at an external barrier for cation uptake as shown by its dependence on the presence of Ca in the external solution. The Ca content of roots is influenced only slightly by changes in external Ca concentrations from 10−4 to 10−2m, but that of shoots is greatly enhanced as the Ca concentration is increased or the K concentration is decreased. These effects on Ca contents are explained as arising from transport to the shoot without involvement of vacuoles of root cells. PMID:16657186

  11. Myth or Reality-Transdermal Magnesium?

    PubMed

    Gröber, Uwe; Werner, Tanja; Vormann, Jürgen; Kisters, Klaus

    2017-07-28

    In the following review, we evaluated the current literature and evidence-based data on transdermal magnesium application and show that the propagation of transdermal magnesium is scientifically unsupported. The importance of magnesium and the positive effects of magnesium supplementation are extensively documented in magnesium deficiency, e.g., cardiovascular disease and diabetes mellitus. The effectiveness of oral magnesium supplementation for the treatment of magnesium deficiency has been studied in detail. However, the proven and well-documented oral magnesium supplementation has become questioned in the recent years through intensive marketing for its transdermal application (e.g., magnesium-containing sprays, magnesium flakes, and magnesium salt baths). In both, specialist and lay press as well as on the internet, there are increasing numbers of articles claiming the effectiveness and superiority of transdermal magnesium over an oral application. It is claimed that the transdermal absorption of magnesium in comparison to oral application is more effective due to better absorption and fewer side effects as it bypasses the gastrointestinal tract.

  12. Synthesis of nanoscale magnesium diboride powder

    DOE PAGES

    Finnemore, D. K.; Marzik, J. V.

    2015-12-18

    A procedure has been developed for the preparation of small grained magnesium diboride (MgB2) powder by reacting nanometer size boron powder in a magnesium vapor. Plasma synthesized boron powder that had particle sizes ranging from 20 to 300nm was mixed with millimeter size chunks of Mg by rolling stoichiometric amounts of the powders in a sealed cylindrical container under nitrogen gas. This mixture then was placed in a niobium reaction vessel, evacuated, and sealed by e-beam welding. The vessel was typically heated to approximately 830°C for several hours. The resulting MgB2 particles have a grain size in the 200 nmmore » to 800 nm range. Agglomerates of loosely bound particles could be broken up by light grinding in a mortar and pestle. At 830°C, many particles are composed of several grains grown together so that the average particle size is about twice the average grain size. Furthermore, experiments were conducted primarily with undoped boron powder, but carbon-doped boron powder showed very similar results.« less

  13. Synthesis of nanoscale magnesium diboride powder

    SciTech Connect

    Finnemore, D. K.; Marzik, J. V.

    2015-12-18

    A procedure has been developed for the preparation of small grained magnesium diboride (MgB2) powder by reacting nanometer size boron powder in a magnesium vapor. Plasma synthesized boron powder that had particle sizes ranging from 20 to 300nm was mixed with millimeter size chunks of Mg by rolling stoichiometric amounts of the powders in a sealed cylindrical container under nitrogen gas. This mixture then was placed in a niobium reaction vessel, evacuated, and sealed by e-beam welding. The vessel was typically heated to approximately 830°C for several hours. The resulting MgB2 particles have a grain size in the 200 nm to 800 nm range. Agglomerates of loosely bound particles could be broken up by light grinding in a mortar and pestle. At 830°C, many particles are composed of several grains grown together so that the average particle size is about twice the average grain size. Furthermore, experiments were conducted primarily with undoped boron powder, but carbon-doped boron powder showed very similar results.

  14. Synthesis of nanoscale magnesium diboride powder

    NASA Astrophysics Data System (ADS)

    Finnemore, D. K.; Marzik, J. V.

    2015-12-01

    A procedure has been developed for the preparation of small grained magnesium diboride (MgB2) powder by reacting nanometer size boron powder in a magnesium vapor. Plasma synthesized boron powder that had particle sizes ranging from 20 to 300nm was mixed with millimeter size chunks of Mg by rolling stoichiometric amounts of the powders in a sealed cylindrical container under nitrogen gas. This mixture then was placed in a niobium reaction vessel, evacuated, and sealed by e-beam welding. The vessel was typically heated to approximately 830°C for several hours. The resulting MgB2 particles have a grain size in the 200 nm to 800 nm range. Agglomerates of loosely bound particles could be broken up by light grinding in a mortar and pestle. At 830°C, many particles are composed of several grains grown together so that the average particle size is about twice the average grain size. Experiments were conducted primarily with undoped boron powder, but carbon-doped boron powder showed very similar results.

  15. Measurements of the {sup 25}Mg({sup 11}B,{sup 12}C){sup 24}Na and {sup 25}Mg({sup 11}B,{sup 10}Be){sup 26}Al proton transfer reactions

    SciTech Connect

    Faria, P. N. de; Lichtenthaeler, R.; Guimaraes, V.; Lepine-Szily, A.; Benjamim, E. A.; Lima, G. F.; Moro, A. M.

    2006-08-15

    Angular distributions for the {sup 11}B+{sup 25}Mg elastic scattering, {sup 25}Mg({sup 11}B,{sup 12}C){sup 24}Na proton pickup, and {sup 25}Mg({sup 11}B,{sup 10}Be){sup 26}Al stripping reactions have been measured at E{sub {sup 11}B}=35 MeV. The angular distributions have been analyzed by the distorted-waves Born approximation calculations using the code fresco. The spectroscopic factors for the overlaps <{sup 25}Mg|{sup 26}Al>,<{sup 25}Mg|{sup 24}Na> for the ground state and excited states of {sup 26}Al and {sup 24}Na have been obtained and compared to previous measurements and shell-model calculations.

  16. System and process for production of magnesium metal and magnesium hydride from magnesium-containing salts and brines

    DOEpatents

    McGrail, Peter B.; Nune, Satish K.; Motkuri, Radha K.; Glezakou, Vassiliki-Alexandra; Koech, Phillip K.; Adint, Tyler T.; Fifield, Leonard S.; Fernandez, Carlos A.; Liu, Jian

    2016-11-22

    A system and process are disclosed for production of consolidated magnesium metal products and alloys with selected densities from magnesium-containing salts and feedstocks. The system and process employ a dialkyl magnesium compound that decomposes to produce the Mg metal product. Energy requirements and production costs are lower than for conventional processing.

  17. The development of lightweight hydride alloys based on magnesium

    SciTech Connect

    Guthrie, S.E.; Thomas, G.J.; Yang, N.Y.C.; Bauer, W.

    1996-02-01

    The development of a magnesium based hydride material is explored for use as a lightweight hydrogen storage medium. It is found that the vapor transport of magnesium during hydrogen uptake greatly influences the surface and hydride reactions in these alloys. This is exploited by purposely forming near-surface phases of Mg{sub 2}Ni on bulk Mg-Al-Zn alloys which result in improved hydrogen adsorption and desorption behavior. Conditions were found where these near-surface reactions yielded a complex and heterogeneous microstructure that coincided with excellent bulk hydride behavior. A Mg-Al alloy hydride is reported with near atmospheric plateau pressures at temperatures below 200{degrees}C. Additionally, a scheme is described for low temperature in-situ fabrication of Mg{sub 2}Ni single phase alloys utilizing the high vapor pressure of Mg.

  18. Magnesium reduces calcification in bovine vascular smooth muscle cells in a dose-dependent manner

    PubMed Central

    Peter, Mirjam E.; Sevinc Ok, Ebru; Celenk, Fatma Gul; Yilmaz, Mumtaz; Steppan, Sonja; Asci, Gulay; Ok, Ercan; Passlick-Deetjen, Jutta

    2012-01-01

    Background. Vascular calcification (VC), mainly due to elevated phosphate levels, is one major problem in patients suffering from chronic kidney disease. In clinical studies, an inverse relationship between serum magnesium and VC has been reported. However, there is only few information about the influence of magnesium on calcification on a cellular level available. Therefore, we investigated the effect of magnesium on calcification induced by β-glycerophosphate (BGP) in bovine vascular smooth muscle cells (BVSMCs). Methods. BVSMCs were incubated with calcification media for 14 days while simultaneously increasing the magnesium concentration. Calcium deposition, transdifferentiation of cells and apoptosis were measured applying quantification of calcium, von Kossa and Alizarin red staining, real-time reverse transcription–polymerase chain reaction and annexin V staining, respectively. Results. Calcium deposition in the cells dramatically increased with addition of BGP and could be mostly prevented by co-incubation with magnesium. Higher magnesium levels led to inhibition of BGP-induced alkaline phosphatase activity as well as to a decreased expression of genes associated with the process of transdifferentiation of BVSMCs into osteoblast-like cells. Furthermore, estimated calcium entry into the cells decreased with increasing magnesium concentrations in the media. In addition, higher magnesium concentrations prevented cell damage (apoptosis) induced by BGP as well as progression of already established calcification. Conclusions. Higher magnesium levels prevented BVSMC calcification, inhibited expression of osteogenic proteins, apoptosis and further progression of already established calcification. Thus, magnesium is influencing molecular processes associated with VC and may have the potential to play a role for VC also in clinical situations. PMID:21750166

  19. [Development of biodegradable magnesium-based biomaterials].

    PubMed

    Zhu, Shengfa; Xu, Li; Huang, Nan

    2009-04-01

    Magnesium is a macroelement which is indispensable to human bodies. As a lightweight metal with high specific strength and favorable biocompatibility, magnesium and its alloys have been introduced in the field of biomedical materials research and have a broad application prospect. It is possible to develop new type of biodegradable medical magnesium alloys by use of the poor corrosion resistance of magnesium. Bioabsorbable magnesium stents implanted in vivo could mechanically support the vessel in a short term, effectly prevent the acute coronary occlusion and in-stent restenosis, and then be gradully biodegraded and completely absorbed in a long term. Osteoconductive bioactivity in magnesium-based alloys could promote the apposition growth of bone tissue. This paper reviews the progress of magnesium and its alloys applied in bone tissue and cardiovascular stents, and the prospect of the future research of magnesium-based biomaterials is discussed.

  20. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... a white precipitate by the addition of sodium hydroxide to a water soluble magnesium salt or by hydration of reactive grades of magnesium oxide. (b) The ingredient meets the specifications of the Food...

  1. 21 CFR 184.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... is prepared as a white precipitate by the addition of sodium hydroxide to a water soluble magnesium salt or by hydration of reactive grades of magnesium oxide. (b) The ingredient meets the specifications...

  2. Magnesium/Calcium Competition at Excitable Membranes.

    ERIC Educational Resources Information Center

    Belzer, Bill; Fry, Panni

    1998-01-01

    Considers some consequences of altering intracellular calcium supply by magnesium concentration changes. Focuses on using this procedure as an exercise with allied health students as they witness therapeutic uses of magnesium and other calcium entry inhibitors. (DDR)

  3. Magnesium/Calcium Competition at Excitable Membranes.

    ERIC Educational Resources Information Center

    Belzer, Bill; Fry, Panni

    1998-01-01

    Considers some consequences of altering intracellular calcium supply by magnesium concentration changes. Focuses on using this procedure as an exercise with allied health students as they witness therapeutic uses of magnesium and other calcium entry inhibitors. (DDR)

  4. Magnesium silicide intermetallic alloys

    NASA Astrophysics Data System (ADS)

    Li, Gh.; Gill, H. S.; Varin, R. A.

    1993-11-01

    Methods of induction melting an ultra-low-density magnesium silicide (Mg2Si) intermetallic and its alloys and the resulting microstructure and microhardness were studied. The highest quality ingots of Mg2Si alloys were obtained by triple melting in a graphite crucible coated with boron nitride to eliminate reactivity, under overpressure of high-purity argon (1.3 X 105 Pa), at a temperature close to but not exceeding 1105 °C ± 5 °C to avoid excessive evaporation of Mg. After establishing the proper induction-melting conditions, the Mg-Si binary alloys and several Mg2Si alloys macroalloyed with 1 at. pct of Al, Ni, Co, Cu, Ag, Zn, Mn, Cr, and Fe were induction melted and, after solidification, investigated by optical microscopy and quantitative X-ray energy dispersive spectroscopy (EDS). Both the Mg-rich and Si-rich eutectic in the binary alloys exhibited a small but systematic increase in the Si content as the overall composition of the binary alloy moved closer toward the Mg2Si line compound. The Vickers microhardness (VHN) of the as-solidified Mg-rich and Si-rich eutectics in the Mg-Si binary alloys decreased with increasing Mg (decreasing Si) content in the eutectic. This behavior persisted even after annealing for 75 hours at 0.89 pct of the respective eutectic temperature. The Mg-rich eutectic in the Mg2Si + Al, Ni, Co, Cu, Ag, and Zn alloys contained sections exhibiting a different optical contrast and chemical composition than the rest of the eutectic. Some particles dispersed in the Mg2Si matrix were found in the Mg2Si + Cr, Mn, and Fe alloys. The EDS results are presented and discussed and compared with the VHN data.

  5. Solid-state rechargeable magnesium battery

    DOEpatents

    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.

  6. 21 CFR 184.1425 - Magnesium carbonate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium carbonate. 184.1425 Section 184.1425 Food... Specific Substances Affirmed as GRAS § 184.1425 Magnesium carbonate. (a) Magnesium carbonate (molecular formula approximately (MgCO3)4·Mg(OH)2·5H2O, CAS Reg. No. 39409-82-0) is also known as magnesium carbonate...

  7. 21 CFR 184.1440 - Magnesium stearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium stearate. 184.1440 Section 184.1440 Food... Specific Substances Affirmed as GRAS § 184.1440 Magnesium stearate. (a) Magnesium stearate (Mg(C17H34COO)2, CAS Reg. No. 557-04-0) is the magnesium salt of stearic acid. It is produced as a white precipitate by...

  8. 21 CFR 184.1440 - Magnesium stearate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium stearate. 184.1440 Section 184.1440 Food... Specific Substances Affirmed as GRAS § 184.1440 Magnesium stearate. (a) Magnesium stearate (Mg(C17H34COO)2, CAS Reg. No. 557-04-0) is the magnesium salt of stearic acid. It is produced as a white precipitate by...

  9. 21 CFR 184.1426 - Magnesium chloride.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium chloride. 184.1426 Section 184.1426 Food... GRAS § 184.1426 Magnesium chloride. (a) Magnesium chloride (MgC12·6H2O, CAS Reg. No. 7786-30-3) is a... prepared by dissolving magnesium oxide, hydroxide, or carbonate in aqueous hydrochloric acid solution and...

  10. 21 CFR 184.1425 - Magnesium carbonate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium carbonate. 184.1425 Section 184.1425... Listing of Specific Substances Affirmed as GRAS § 184.1425 Magnesium carbonate. (a) Magnesium carbonate (molecular formula approximately (MgCO3)4·Mg(OH)2·5H2O, CAS Reg. No. 39409-82-0) is also known as magnesium...

  11. 21 CFR 184.1440 - Magnesium stearate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium stearate. 184.1440 Section 184.1440 Food... Specific Substances Affirmed as GRAS § 184.1440 Magnesium stearate. (a) Magnesium stearate (Mg(C17H34COO)2, CAS Reg. No. 557-04-0) is the magnesium salt of stearic acid. It is produced as a white precipitate by...

  12. 21 CFR 184.1440 - Magnesium stearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium stearate. 184.1440 Section 184.1440 Food... Specific Substances Affirmed as GRAS § 184.1440 Magnesium stearate. (a) Magnesium stearate (Mg(C17H34COO)2, CAS Reg. No. 557-04-0) is the magnesium salt of stearic acid. It is produced as a white precipitate by...

  13. 21 CFR 184.1425 - Magnesium carbonate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium carbonate. 184.1425 Section 184.1425... GRAS § 184.1425 Magnesium carbonate. (a) Magnesium carbonate (molecular formula approximately (MgCO3)4·Mg(OH)2·5H2O, CAS Reg. No. 39409-82-0) is also known as magnesium carbonate hydroxide. It is a white...

  14. 21 CFR 184.1425 - Magnesium carbonate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium carbonate. 184.1425 Section 184.1425... Listing of Specific Substances Affirmed as GRAS § 184.1425 Magnesium carbonate. (a) Magnesium carbonate (molecular formula approximately (MgCO3)4·Mg(OH)2·5H2O, CAS Reg. No. 39409-82-0) is also known as magnesium...

  15. 21 CFR 184.1425 - Magnesium carbonate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium carbonate. 184.1425 Section 184.1425... Listing of Specific Substances Affirmed as GRAS § 184.1425 Magnesium carbonate. (a) Magnesium carbonate (molecular formula approximately (MgCO3)4·Mg(OH)2·5H2O, CAS Reg. No. 39409-82-0) is also known as magnesium...

  16. 21 CFR 184.1440 - Magnesium stearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium stearate. 184.1440 Section 184.1440 Food... GRAS § 184.1440 Magnesium stearate. (a) Magnesium stearate (Mg(C17H34COO)2, CAS Reg. No. 557-04-0) is the magnesium salt of stearic acid. It is produced as a white precipitate by the addition of an...

  17. Magnesium in sea water: an electrode measurement.

    PubMed

    Thompson, M E

    1966-08-19

    Magnesium ion in standard I.A.P.O. sea water was measured with a magnesium-sensitive electrode. The results, presented either as magnesiumion activity (0.017) or as the amount of ionized magnesium (0.048M or about 90 percent of the total magnesium), agree well with the data from the chemical model for sea water proprosed by Garrels and Thompson.

  18. Dislocation structure of the magnesium nanocrystal in uniaxial loading

    NASA Astrophysics Data System (ADS)

    Vlasova, A. M.; Nikonov, A. Yu.; Zhuravlev, A. K.; Kesarev, A. G.

    2016-11-01

    We report on molecular-dynamics (MD) simulations of compression loading of nanocrystalline magnesium modeled by the embedded-atom method (EAM) potential. It is shown that plastic deformation is by basal slip and (102) twinning. The formation of stable configurations of dislocation grids is observed. Some dislocation reactions are suggested to explain the occurrence of grids. The structure of the dislocation core is shown with the Burgers vector 1 /18 [0 4 ¯43 ] .

  19. Physicochemical properties of magnesium salicylate.

    PubMed

    Alam, A S; Gregoriades, D

    1981-08-01

    Magnesium salicylate tetrahydrate is a nonhygroscopic, crystalline powder, whereas anhydrous magnesium salicylate is amorphous and very hygroscopic. Magnesium salicylate tetrahydrate tablets formulated with gelatin as a binder showed a dissolution half-life (t1/2) of 12 min, whereas a formulation using pregelatinized starch as a binder showed a t1/2 of 33 min. The optimum level of calcium stearate in the formulation was determined by the oscilloscope tracings of compressional and ejectional forces from an instrumented rotary tableting machine. Increasing the level of calcium stearate from 1 to 1.5 and 2% resulted in dissolution t1/2 values of 12, 18, and 21 min, respectively, and a higher incidence of softer tablets and capping.

  20. 21 CFR 582.1431 - Magnesium oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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 is...

  1. 76 FR 69284 - Pure Magnesium From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    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. 731-TA-696...

  2. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  3. 21 CFR 582.1431 - Magnesium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 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 is...

  4. Synthesis of superconducting magnesium diboride objects

    DOEpatents

    Finnemore, Douglas K.; Canfield, Paul C.; Bud'ko, Sergey L.; Ostenson, Jerome E.; Petrovic, Cedomir; Cunningham, Charles E.; Lapertot, Gerard

    2003-08-15

    A process to produce magnesium diboride objects from boron objects with a similar form is presented. Boron objects are reacted with magnesium vapor at a predetermined time and temperature to form magnesium diboride objects having a morphology similar to the boron object's original morphology.

  5. 21 CFR 582.2437 - Magnesium silicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Magnesium silicate. 582.2437 Section 582.2437 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Magnesium silicate. (a) Product. Magnesium silicate. (b) Tolerance. 2 percent. (c) Limitations, restrictions...

  6. 21 CFR 582.1425 - Magnesium carbonate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Magnesium carbonate. 582.1425 Section 582.1425 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use. This...

  7. 21 CFR 582.1431 - Magnesium oxide.

    Code of Federal Regulations, 2010 CFR

    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 is...

  8. 21 CFR 201.71 - Magnesium labeling.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Magnesium labeling. 201.71 Section 201.71 Food and... LABELING Labeling Requirements for Over-the-Counter Drugs § 201.71 Magnesium labeling. (a) The labeling of over-the-counter (OTC) drug products intended for oral ingestion shall contain the magnesium content...

  9. 21 CFR 582.1425 - Magnesium carbonate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Magnesium carbonate. 582.1425 Section 582.1425 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use. This...

  10. Synthesis Of Superconducting Magnesium Diboride Objects.

    DOEpatents

    Finnemore, Douglas K.; Canfield, Paul C.; Bud'ko, Sergey L.; Ostenson, Jerome E.; Petrovic, Cedomir; Cunningham, Charles E.; Lapertot, Gerard

    2003-07-08

    A process to produce magnesium diboride objects from boron objects with a similar form is presented. Boron objects are reacted with magnesium vapor at a predetermined time and temperature to form magnesium diboride objects having a morphology similar to the boron object's original morphology.

  11. 21 CFR 582.5443 - Magnesium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 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. This...

  12. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  13. 21 CFR 201.71 - Magnesium labeling.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Magnesium labeling. 201.71 Section 201.71 Food and... LABELING Labeling Requirements for Over-the-Counter Drugs § 201.71 Magnesium labeling. (a) The labeling of over-the-counter (OTC) drug products intended for oral ingestion shall contain the magnesium content...

  14. 21 CFR 582.1425 - Magnesium carbonate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium carbonate. 582.1425 Section 582.1425 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use. This...

  15. 21 CFR 582.5431 - Magnesium oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 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 substance...

  16. 21 CFR 582.1425 - Magnesium carbonate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Magnesium carbonate. 582.1425 Section 582.1425 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use. This...

  17. 21 CFR 582.2437 - Magnesium silicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Magnesium silicate. 582.2437 Section 582.2437 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Magnesium silicate. (a) Product. Magnesium silicate. (b) Tolerance. 2 percent. (c) Limitations, restrictions...

  18. 21 CFR 582.2437 - Magnesium silicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Magnesium silicate. 582.2437 Section 582.2437 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Magnesium silicate. (a) Product. Magnesium silicate. (b) Tolerance. 2 percent. (c) Limitations, restrictions...

  19. 21 CFR 201.71 - Magnesium labeling.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Magnesium labeling. 201.71 Section 201.71 Food and... LABELING Labeling Requirements for Over-the-Counter Drugs § 201.71 Magnesium labeling. (a) The labeling of over-the-counter (OTC) drug products intended for oral ingestion shall contain the magnesium content...

  20. 21 CFR 582.5443 - Magnesium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 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. This...

  1. 21 CFR 182.2437 - Magnesium silicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium silicate. 182.2437 Section 182.2437 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Magnesium silicate. (a) Product. Magnesium silicate. (b) Tolerance. 2 percent. (c) Limitations, restrictions...

  2. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  3. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  4. 21 CFR 182.2437 - Magnesium silicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium silicate. 182.2437 Section 182.2437 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Anticaking Agents § 182.2437 Magnesium silicate. (a) Product. Magnesium...

  5. 21 CFR 582.5443 - Magnesium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 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. This...

  6. 21 CFR 182.2437 - Magnesium silicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium silicate. 182.2437 Section 182.2437 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Magnesium silicate. (a) Product. Magnesium silicate. (b) Tolerance. 2 percent. (c) Limitations, restrictions...

  7. 21 CFR 182.2437 - Magnesium silicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium silicate. 182.2437 Section 182.2437 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Magnesium silicate. (a) Product. Magnesium silicate. (b) Tolerance. 2 percent. (c) Limitations, restrictions...

  8. 21 CFR 182.2437 - Magnesium silicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium silicate. 182.2437 Section 182.2437 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Magnesium silicate. (a) Product. Magnesium silicate. (b) Tolerance. 2 percent. (c) Limitations, restrictions...

  9. 21 CFR 582.5431 - Magnesium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 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 substance...

  10. 21 CFR 582.2437 - Magnesium silicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Magnesium silicate. 582.2437 Section 582.2437 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Magnesium silicate. (a) Product. Magnesium silicate. (b) Tolerance. 2 percent. (c) Limitations, restrictions...

  11. 21 CFR 582.1428 - Magnesium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  12. 21 CFR 582.2437 - Magnesium silicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium silicate. 582.2437 Section 582.2437 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Magnesium silicate. (a) Product. Magnesium silicate. (b) Tolerance. 2 percent. (c) Limitations, restrictions...

  13. 21 CFR 582.1431 - Magnesium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 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 is...

  14. 21 CFR 582.5431 - Magnesium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 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 substance...

  15. 21 CFR 582.1431 - Magnesium oxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 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 is...

  16. 21 CFR 582.1425 - Magnesium carbonate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Magnesium carbonate. 582.1425 Section 582.1425 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use. This...

  17. 21 CFR 582.5443 - Magnesium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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. This...

  18. 21 CFR 582.5431 - Magnesium oxide.

    Code of Federal Regulations, 2010 CFR

    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 substance...

  19. 21 CFR 582.5434 - Magnesium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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). (b...

  20. 21 CFR 582.5431 - Magnesium oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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 substance...

  1. 21 CFR 582.5434 - Magnesium phosphate.

    Code of Federal Regulations, 2010 CFR

    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). (b...

  2. 21 CFR 582.5443 - Magnesium sulfate.

    Code of Federal Regulations, 2010 CFR

    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. This...

  3. 21 CFR 582.5434 - Magnesium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 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). (b...

  4. 21 CFR 582.5434 - Magnesium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 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). (b...

  5. 21 CFR 582.5434 - Magnesium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 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). (b...

  6. Neonatal serum magnesium concentrations are determined by total maternal dose of magnesium sulfate administered for neuroprotection.

    PubMed

    Borja-Del-Rosario, Pamela; Basu, Sudeepta Kumar; Haberman, Shoshana; Bhutada, Alok; Rastogi, Shantanu

    2014-03-01

    Antenatal magnesium in preterm labor for neuroprotection decreases the incidence of cerebral palsy. However, there are no guidelines on the dose and duration of magnesium infusion for neuroprotection. As increased neonatal serum magnesium concentrations may be related to higher risk of morbidity and mortality, the role of total amount of magnesium and maternal serum magnesium concentrations associated with safe neonatal serum magnesium concentrations is not known. A retrospective study was conducted on 289 mothers who received antenatal magnesium for neuroprotection as a loading dose of 4-6 g infused over 30 min, followed by a maintenance infusion of 1-2 g/h. Total magnesium dose infused to the mother and maternal serum magnesium concentrations were correlated with neonatal serum magnesium concentrations. Of the 289 mothers, 192 mother/baby dyads had all three measurements (maternal total magnesium dose, and maternal and neonatal serum magnesium concentrations). Magnesium infusion was continued beyond 24 h in 60 mothers. Total maternal magnesium dose at 24 and 48 h of infusion correlated with neonatal serum magnesium concentrations (r=0.55, P<0.0001 and r=0.35, P<0.0001, respectively), but not with maternal serum magnesium concentrations (r=0.004, P=0.98 and r=0.14, P=0.21). However, there was no correlation between the maternal and neonatal serum magnesium concentrations (r=0.10, P=0.15). Total dose of magnesium infused to the mother correlates with neonatal serum magnesium concentrations. To keep neonatal serum magnesium concentrations within a range that is effective for neuroprotection and safe for the neonates, the total dose received by the mother needs to be monitored and limited.

  7. Abnormal magnesium status in patients with cardiovascular diseases.

    PubMed

    Sasaki, S; Oshima, T; Matsuura, H; Ozono, R; Higashi, Y; Sasaki, N; Matsumoto, T; Nakano, Y; Ueda, A; Yoshimizu, A; Kurisu, S; Kambe, M; Kajiyama, G

    2000-02-01

    To investigate magnesium status in patients with cardiovascular diseases and in those presenting high factors for these diseases, we measured the concentrations of serum total Mg, serum ionized Mg and intra-erythrocyte Mg. Mg is an important cofactor for many enzymes, especially those involved in phosphate transfer reactions. Mg deficiency has been shown to be associated with fatal cardiovascular diseases, as well as with risk factors for these diseases. Only measurement of the serum concentration of total Mg is routinely available, but ionized Mg is the physiologically active component. Furthermore, most of the body's Mg is present in the intracellular space. Subjects included patients with ischaemic heart disease (n=80), cardiac arrhythmia (n=60), diabetes mellitus (n=36), essential hypertension (n=194) and hypercholesterolaemia (n=60). The same measurements were made in healthy controls (30 men and 26 women; mean age 58+/-11 years). The serum ionized Mg concentration was measured with a selective ion electrode. The intra-erythrocyte Mg concentration was measured by atomic absorption. No gender difference was found for any Mg parameter, nor was age related to any Mg parameter. The serum albumin concentration was positively correlated only with the serum total Mg concentration. Although the serum total Mg concentration was similar in all groups, patients with diabetes mellitus and arrhythmia had lower serum levels of ionized Mg. Patients with essential hypertension exhibited higher intra-erythrocyte Mg concentrations than the healthy controls. Thus the measurement of serum total Mg concentration may obscure the presence of extracellular Mg deficiency in patients with arrhythmia and diabetes mellitus. Furthermore, the intracellular accumulation of Mg does not support the hypothesis of Mg deficiency in patients with essential hypertension.

  8. Laser glazing of lanthanum magnesium hexaaluminate

    NASA Astrophysics Data System (ADS)

    Zhang, Yanfei; Wang, Yaomin; Jarligo, Maria Ophelia; Zhong, Xinghua; Li, Qin; Cao, Xueqiang

    2008-08-01

    Lanthanum magnesium hexaalumminate (LMA) is an important candidate for thermal barrier coatings due to its thermal stability and low thermal conductivity. On the other hand, laser glazing method can potentially make thermal barrier coatings impermeable, resistant to corrosion on the surface and porous at bulk. LMA powder was synthesized at 1600 °C by solid-state reaction, pressed into tablet and laser glazed with a 5-kW continuous wave CO2 laser. Dendritic structures were observed on the surface of the laser-glazed specimen. The thicker the tablet, the easier the sample cracks. Cracking during laser glazing is attributed to the low thermal expansion coefficient and large thickness of the sample.

  9. Magnesium Diboride Current Leads

    NASA Technical Reports Server (NTRS)

    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.

  10. ReaxFF(MgH) reactive force field for magnesium hydride systems.

    PubMed

    Cheung, Sam; Deng, Wei-Qiao; van Duin, Adri C T; Goddard, William A

    2005-02-10

    We have developed a reactive force field (ReaxFF(MgH)) for magnesium and magnesium hydride systems. The parameters for this force field were derived from fitting to quantum chemical (QM) data on magnesium clusters and on the equations of states for condensed phases of magnesium metal and magnesium hydride crystal. The force field reproduces the QM-derived cell parameters, density, and the equations of state for various pure Mg and MgH(2) crystal phases as well as and bond dissociation, angle bending, charge distribution, and reaction energy data for small magnesium hydride clusters. To demonstrate one application of ReaxFF(MgH), we have carried out MD simulations on the hydrogen absorption/desorption process in magnesium hydrides, focusing particularly on the size effect of MgH(2) nanoparticles on H(2) desorption kinetics. Our results show a clear relationship between grain size and heat of formation of MgH(2); as the particle size decreases, the heat of formation increases. Between 0.6 and 2.0 nm, the heat of formation ranges from -16 to -19 kcal/Mg and diverges toward that of the bulk value (-20.00 kcal/Mg) as the particle diameter increases beyond 2 nm. Therefore, it is not surprising to find that Mg nanoparticles formed by ball milling (20-100 nm) do not exhibit any significant change in thermochemical properties.

  11. [Magnesium deficiency in an endocrinologist's practice].

    PubMed

    Tereshchenko, I V

    2008-01-01

    The review concerning a value of magnesium in an organism in healthy persons and cases with endocrine disorders is presented. The causes of magnesium-deficient conditions in cases with type 1 and type 2 diabetes, thyrotoxic goiter, hypothyroidism and obesity were analyzed. Participation of magnesium in secretion of parathormone and a control of calcium exchange is shown. The clinical semiology of hypomagnesemia seems to be nonspecific and manifold, and, therefore, as a rule, in most of endocrine patients magnesium deficiency remains to be undiagnosed. Questions on preventive measures and management of treatment magnesium-deficient conditions are considered.

  12. Major Minerals - Calcium, Magnesium, Phosphorus

    USDA-ARS?s Scientific Manuscript database

    Calcium, magnesium and phosphorus are essential elements critically important for the function of the musculoskeletal system, including the formation and transduction of energy and the maintenance of healthy bone. The major calcium concern for physically active healthy middle-aged adults is to consu...

  13. Chemical conversion coating for protecting magnesium alloys from corrosion

    DOEpatents

    Bhargava, Gaurang; Allen, Fred M.; Skandan, Ganesh; Hornish, Peter; Jain, Mohit

    2016-01-05

    A chromate-free, self-healing conversion coating solution for magnesium alloy substrates, composed of 10-20 wt. % Mg(NO.sub.3).sub.2.6H.sub.2O, 1-5 wt. % Al(NO.sub.3).sub.3.9H.sub.2O, and less than 1 wt. % of [V.sub.10O.sub.28].sup.6- or VO.sub.3.sup.- dissolved in water. The corrosion resistance offered by the resulting coating is in several hundreds of hours in salt-spray testing. This prolonged corrosion protection is attributed to the creation of a unique structure and morphology of the conversion coating that serves as a barrier coating with self-healing properties. Hydroxoaluminates form the backbone of the barrier protection offered while the magnesium hydroxide domains facilitate the "slow release" of vanadium compounds as self-healing moieties to defect sites, thus providing active corrosion protection.

  14. Quantitatively Predict the Potential of MnO2 Polymorphs as Magnesium Battery Cathodes.

    PubMed

    Ling, Chen; Zhang, Ruigang; Mizuno, Fuminori

    2016-02-01

    Despite tremendous efforts denoted to magnesium battery research, the realization of magnesium battery is still challenged by the lack of cathode candidate with high energy density, rate capability and good recyclability. This situation can be largely attributed to the failure to achieve sustainable magnesium intercalation chemistry. In current work we explored the magnesiation of distinct MnO2 polymorphs using first-principles calculations, focusing on providing quantitative analysis about the feasibility of magnesium intercalation. Consistent with experimental observations, we predicted that ramsdellite-MnO2 and α-MnO2 are conversion-type cathodes while nanosized spinel-MnO2 and MnO2 isostructual to CaFe2O4 are better candidates for Mg intercalation. Key properties that restrict Mg intercalation include not only sluggish Mg migration but also stronger distortion that damages structure integrity and undesirable conversion reaction. We demonstrate that by evaluating the reaction free energy, structural deformation associated with the insertion of magnesium, and the diffusion barriers, a quantitative evaluation about the feasibility of magnesium intercalation can be well established. Although our current work focuses on the study of MnO2 polymorphs, the same evaluation can be applied to other cathode candidates, thus paving the road to identify better cathode candidates in future.

  15. A SEARCH FOR MAGNESIUM IN EUROPA'S ATMOSPHERE

    SciTech Connect

    Hoerst, S. M.; Brown, M. E.

    2013-02-20

    Europa's tenuous atmosphere results from sputtering of the surface. The trace element composition of its atmosphere is therefore related to the composition of Europa's surface. Magnesium salts are often invoked to explain Galileo Near Infrared Mapping Spectrometer spectra of Europa's surface, thus magnesium may be present in Europa's atmosphere. We have searched for magnesium emission in the Hubble Space Telescope Faint Object Spectrograph archival spectra of Europa's atmosphere. Magnesium was not detected and we calculate an upper limit on the magnesium column abundance. This upper limit indicates that either Europa's surface is depleted in magnesium relative to sodium and potassium, or magnesium is not sputtered as efficiently resulting in a relative depletion in its atmosphere.

  16. [Magnesium: a kardio-renal viewpoint].

    PubMed

    Brandenburg, Vincent Matthias; Kaesler, Nadine; Kramann, Rafael; Floege, Jürgen; Marx, Nikolaus

    2016-10-01

    Disturbances in magnesium homeostasis are frequent clinical conditions, particularly the prevalence of hypomagnesaemia is high. However, it remains an open question which laboratory method is optimal to assess the magnesium level in the body. Most frequently physicians measure total magnesium in serum. Many associative data from observational studies point towards an association between low magnesium levels and increased cardiovascular risk as well as increased mortality. Vice versa, normal-to-high magnesium levels in patients with advanced renal failure translate to a better outcome. The present review summarizes our knowledge on protective effects of magnesium. Additionally, we address the limited evidence supporting targeted magnesium supplementation. © Georg Thieme Verlag KG Stuttgart · New York.

  17. Effects of proton irradiation on a gas phase in which condensation takes place. I Negative Mg-26 anomalies and Al-26. [applied to solar and meteoritic composition

    NASA Technical Reports Server (NTRS)

    Heymann, D.; Dziczkaniec, M.; Walker, A.; Huss, G.; Morgan, J. A.

    1978-01-01

    In the present paper, isotopic effects in magnesium generated in a proton-irradiated gas phase are examined, taking only (p,n), (p,d), and (p, alpha) reactions in magnesium, aluminum, and silicon into consideration. In the presence of proton radiation, the three elements are 'removed' from the gas phase by condensation. It is required that a value of Al-26/Al-27 greater than 6 times 10 to the -5th must be reached, consistent with the value deduced by Lee Papanastassiou, and Wasserburg (1976) from their studies of the Allende meteorite. The calculations show that fast aluminum condensation reduces the required proton fluence substantially, that a significant fraction of aluminum remains uncondensed when the above value of the Al-26/Al-27 ratio is reached, that a detectable MG-24 excess is very likely to occur, that detectable negative MG-28 anomalies can be generated, and that proton fluxes and irradiation times can be varied simultaneously, and over a wide range of values, without significant changes in the required proton fluence.

  18. Hydrated magnesium cations Mg+(H2O)n, n ≈ 20-60, exhibit chemistry of the hydrated electron in reactions with O2 and CO2.

    PubMed

    van der Linde, Christian; Akhgarnusch, Amou; Siu, Chi-Kit; Beyer, Martin K

    2011-09-15

    Ion-molecule reactions of Mg(+)(H(2)O)(n), n ≈ 20-60, with O(2) and CO(2) are studied by Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry. O(2) and CO(2) are taken up by the clusters. Both reactions correspond to the chemistry of hydrated electrons (H(2)O)(n)(-). Density functional theory calculations predicted that the solvation structures of Mg(+)(H(2)O)(16) contain a hydrated electron that is solvated remotely from a hexa-coordinated Mg(2+). Ion-molecule reactions between Mg(+)(H(2)O)(16) and O(2) or CO(2) are calculated to be highly exothermic. Initially, a solvent-separated ion pair is formed, with the hexa-coordinated Mg(2+) ionic core being well separated from the O(2)(•-) or CO(2)(•-). Rearrangements of the solvation structure are possible and produce a contact-ion pair in which one water molecule in the first solvation shell of Mg(2+) is replaced by O(2)(•-) or CO(2)(•-). © 2011 American Chemical Society

  19. Thermodynamics and high-pressure kinetics of a fast carbon dioxide fixation reaction by a (2,6-pyridinedicarboxamidato-hydroxo)nickel(II) complex.

    PubMed

    Troeppner, O; Huang, D; Holm, R H; Ivanović-Burmazović, I

    2014-04-14

    The previously reported carbon dioxide fixation reaction by the planar terminal hydroxide complex [Ni(pyN2(Me2))(OH)](1-) in DMF has been further characterized by determination of the equilibrium constants K(eq)²⁹⁸ = 2.4 ± 0.2 × 10(5) M(-1) and K(eq)²²³ = 1.3 ± 0.1 × 10(7) M(-1), as well as the volume of activation for the CO2 binding (ΔV(on)(≠223) = -21 ± 3 cm(3) mol(-1)) and back decarboxylation (ΔV(off)(≠223) = -13 ± 1 cm(3) mol(-1)) by high-pressure kinetics. The data are consistent with an earlier DFT computation, including the probable nature of the transition state, and support designating the reaction as one of the most completely investigated carbon dioxide fixation reactions of any type.

  20. A Study of Magnesium-Base Metallic Systems and Development of Principles for Creation of Corrosion-Resistant Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Mukhina, I. Yu.

    2014-11-01

    The effect of 26 alloying elements on the corrosion resistance of high-purity magnesium in a 0.5-n solution of sodium chloride and in a humid atmosphere (0.005 n) is studied. The Mg - Li, Mg - Ag, Mg - Zn, Mg - Cu, Mg - Gd, Mg - Al, Mg - Zr, Mg - Mn and other binary systems, which present interest as a base for commercial or perspective castable magnesium alloys, are studied. The characteristics of corrosion resistance of the binary alloys are analyzed in accordance with the group and period of the Mendeleev's periodic law. The roles of the electrochemical and volume factors and of the factor of the valence of the dissolved element are determined.

  1. Structural analysis of HS(CD(2))(12)(O-CH(2)-CH(2))(6)OCH(3) monolayers on gold by means of polarization modulation infrared reflection absorption spectroscopy. progress of the reaction with bromine.

    PubMed

    Brand, Izabella; Nullmeier, Martina; Klüner, Thorsten; Jogireddy, Rajamalleswaramma; Christoffers, Jens; Wittstock, Gunther

    2010-01-05

    A self-assembled monolayer (SAM) on gold was formed with specifically perdeuterated hexaethylene glycol-terminated alkanethiol HS(CD(2))(12)(O-CH(2)-CH(2))(6)OCH(3) (D-OEG). The structure of the d-alkane and the oligoethylene glycol (OEG) parts of the molecule in a SAM was studied by means of polarization modulation infrared reflection absorption spectroscopy. The D-OEG monolayers are highly ordered and exist in a crystalline phase. The d-alkane chain adopts an all-trans conformation. Both, the d-alkane chain and long axis of the OEG part make an angle of 26.0 degrees +/- 1.5 degrees with respect to the surface normal, a value characteristic for the tilt of solid n-alkane thiols in the SAMs on Au. The positions of nu(as)(COC) and CH(2) wagging and rocking modes indicate a helical arrangement of the OEG chains. The D-OEG SAMs were exposed to 25 muM Br(2) in two ways: (i) by immersion into the Br(2) solution and (ii) in the galvanic cell Au|D-OEG SAM|25 muM Br(2) + 0.1 M Na(2)SO(4)|| 50 muM KBr + 0.1 M Na(2)SO(4)|Au. In the galvanic cell, the oxidant (Br(2)) is scavenged by a heterogeneous electron transfer reaction, slowing the reaction of D-OEG with Br(2). The slow progress of the reaction with Br(2) allowed us to draw conclusions about molecular rearrangements taking place during this reaction. The reaction with Br(2) starts on boundaries and/or defects present in the SAM. First, at the defect place, the alpha-C atom of the OEG chain reacts with Br(2) and the OEG part of the molecule is removed from the monolayer. In consequence an increase in disorder in the OEG part of the SAM is observed. The same mechanism of the reaction with Br(2) is applied for the d-dodecane alkanethiol part of the molecule. This reaction is slow, thus the order and the tilt of the hydrocarbon chain changes only a little during the reaction time.

  2. Electrochemical Performance Estimation of Anodized AZ31B Magnesium Alloy as Function of Change in the Current Density

    NASA Astrophysics Data System (ADS)

    Girón, L.; Aperador, W.; Tirado, L.; Franco, F.; Caicedo, J. C.

    2017-06-01

    The anodized AZ31B magnesium alloys were synthesized via electrodeposition processes. The aim of this work was to determine the electrochemical behavior of magnesium alloys by using anodized alloys as a protective coating. The anodized alloys were characterized by x-ray diffraction, exhibiting the crystallography orientation for Mg and MgO phases. The x-ray photoelectron spectroscopy was used to determine the chemical composition of anodized magnesium alloys. By using electrochemical impedance spectroscopy and Tafel curves, it was possible to estimate the electrochemical behavior of anodized AZ31B magnesium alloys in Hank's balanced salt solution (HBSS). Scanning electron microscopy was performed to analyze chemical changes and morphological surface changes on anodized Mg alloys due to the reaction in HBSS/anodized magnesium surface interface. Electrochemical behavior in HBSS indicates that the coatings may be a promising material for biomedical industry.

  3. Electrochemical Performance Estimation of Anodized AZ31B Magnesium Alloy as Function of Change in the Current Density

    NASA Astrophysics Data System (ADS)

    Girón, L.; Aperador, W.; Tirado, L.; Franco, F.; Caicedo, J. C.

    2017-08-01

    The anodized AZ31B magnesium alloys were synthesized via electrodeposition processes. The aim of this work was to determine the electrochemical behavior of magnesium alloys by using anodized alloys as a protective coating. The anodized alloys were characterized by x-ray diffraction, exhibiting the crystallography orientation for Mg and MgO phases. The x-ray photoelectron spectroscopy was used to determine the chemical composition of anodized magnesium alloys. By using electrochemical impedance spectroscopy and Tafel curves, it was possible to estimate the electrochemical behavior of anodized AZ31B magnesium alloys in Hank's balanced salt solution (HBSS). Scanning electron microscopy was performed to analyze chemical changes and morphological surface changes on anodized Mg alloys due to the reaction in HBSS/anodized magnesium surface interface. Electrochemical behavior in HBSS indicates that the coatings may be a promising material for biomedical industry.

  4. Evaluation of the skin sensitizing potential of biodegradable magnesium alloys.

    PubMed

    Witte, Frank; Abeln, Inken; Switzer, Elinor; Kaese, Volker; Meyer-Lindenberg, Andrea; Windhagen, Henning

    2008-09-15

    Corroding metals made of magnesium alloys represent a new class of degradable implants for musculoskeletal surgery. These implants may be associated with skin sensitizing reactions because of the release of metal ions. This study was conducted to compare the sensitizing potential of four different magnesium alloys (AZ31, AZ91, WE43, and LAE442) to current implant materials such as titanium (TiAl6V4) and a degradable polymer (SR-PLA96). Solutions and solid chips of these materials were prepared and tested in 156 guinea pigs according to the Magnusson-Kligman test. A standard allergen (hydroxy-cinnamon-aldehyde) causing allergic erythema was used as positive control and a standard irritant (sodium-lauryl-sulfate) causing local skin irritation for less than 24 h was used as negative control. All erythema were graded immediately and 24 h after patch removal by three independent observers. Histomorphological analyses were performed on skin biopsies taken 24 h after patch removal. We found that initial erythema in animals treated with solid chips diminished within 24 h and were caused by local skin irritation. Local skin irritation was also determined in erythema remaining for 24 h after patch removal in animals treated with dissolved test materials. No allergenic reactions according to the histomorphological criteria were observed in skin biopsies. We conclude that no skin sensitizing potential were detected for standard materials as well as for all tested magnesium alloys by the used methods.

  5. Sol gel-fluorination synthesis of amorphous magnesium fluoride

    NASA Astrophysics Data System (ADS)

    Krishna Murthy, J.; Groß, Udo; Rüdiger, Stephan; Kemnitz, Erhard; Winfield, John M.

    2006-03-01

    The sol-gel fluorination process is discussed for the reaction of magnesium alkoxides with HF in non-aqueous solvents to give X-ray amorphous nano-sized magnesium fluoride with high surface areas in the range of 150-350 m 2/g (HS-MgF 2). The H2 type hysteresis of nitrogen adsorption-desorption BET-isotherms is indicative for mesoporous solids. A highly distorted structure causes quite high Lewis acidity, shown by NH 3 temperature-programmed desorption (NH 3-TPD) and catalytic test reactions. XPS data of amorphous and conventionally crystalline MgF 2 are compared, both show octahedral coordination at the metal site. Thermal analysis, F-MAS NMR- and IR-spectroscopy give information on composition and structure of the precursor intermediate as well as of the final metal fluoride. The preparation of complex fluorides, M +MgF 3-, by the sol-gel route is reported. From the magnesium fluoride gel of the above process thin films for optical application are obtained by, e.g., spin coating.

  6. ATP sulfurylase-dependent assays for inorganic pyrophosphate: applications to determining the equilibrium constant and reverse direction kinetics of the pyrophosphatase reaction, magnesium binding to orthophosphate, and unknown concentrations of pyrophosphate.

    PubMed

    Daley, L A; Renosto, F; Segel, I H

    1986-09-01

    A continuous, coupled, spectrophotometric assay is described in which the enzyme ATP sulfurylase is employed to measure the concentration of inorganic pyrophosphate (PPi) at equilibrium with known concentrations of inorganic orthophosphate (Pi) in the presence of excess inorganic pyrophosphatase (PPitase). In agreement with previous reports, the apparent equilibrium constant (Keq,app) of the PPi hydrolysis reaction was shown to decrease as the concentration of Mg2+ is increased. At pH 7.3, 30 degrees C, in the presence of 150 mM NaCl and 1 mM free Mg2+, Keq,app (calculated as [Pi]t2/[PPi]t) was 1950. Measurements of Keq,app at different total concentrations of Mg2+ and Pi permitted the determination of K0, the dissociation constant of the Mg-Pi complex. In 0.05 M Tris-Cl, pH 8.0, at 30 degrees C, K0 was 3.6 mM. In the presence of excess ATP sulfurylase, yeast PPitase catalyzed PPi formation from Pi with a specific activity (Vmax) of 9 units X mg protein-1 at pH 8.0, 30 degrees C, and 1 mM free Mg2+. Half-maximum reverse reaction velocity was observed at a total Pi concentration of 18 mM. (Under the same conditions, Vmax of the PPi hydrolysis reaction was 530 units X mg protein-1.) A radiochemical end point ("reaction-to-completion") assay for measuring unknown concentrations of PPi was devised. In the presence of excess 35S-adenosine-5'-phosphosulfate ([35S]APS) as the cosubstrate, 35SO2-4 formation was stoichiometric with added PPi. (The 35SO2-4 and [35S]APS are separated by adsorption of the latter onto charcoal.) The sensitivity of the assay can be adjusted by varying the specific radioactivity of the [35S]APS. In the absence of interfering substances, as little as 2 pmol of PPi per 1.0 ml assay volume can be measured. The sensitivity of the assay is reduced in the presence of ATP plus perchlorate (which synergistically inhibit the enzyme). However, if the bulk of the ATP is removed from perchloric acid extracts of tissues with glucose and hexokinase, initial

  7. Magnesium in chronic kidney disease: unanswered questions.

    PubMed

    Spiegel, David M

    2011-01-01

    Magnesium ion is critical for life and is integrally involved in cellular function and a key component of normal bone mineral. In health, the kidneys, gastrointestinal tract and bone are responsible for maintaining serum magnesium concentrations in the normal range and magnesium balance. Most clinical disorders involving magnesium, other than chronic kidney disease (CKD), result in hypomagnesemia, either from gastrointestinal or kidney losses. CKD and particularly end-stage kidney disease is the only clinical condition where sustained hypermagnesemia may occur and net magnesium balance may be positive. This review will focus on normal magnesium homeostasis and review the literature in CKD with a particular focus on end-stage kidney disease and the potential role of magnesium as a phosphate binder and in cardiovascular and bone health. A number of small to medium-size interventional trials have shown that magnesium-based compounds can serve as effective phosphate binders. Observational studies suggest that higher serum magnesium concentrations in dialysis patients may improve survival and may slow the progression of vascular calcification. While a few small prospective trials support these findings, no large or long-term studies are available. Magnesium balance remains poorly understood in patients with end-stage kidney disease. While observational and small randomized trials suggest that exogenous administration may be useful as a phosphate binder and may have protective cardiovascular effects in terms of both arrhythmias and vascular calcification, large randomized trials are needed to test these hypotheses. Copyright © 2011 S. Karger AG, Basel.

  8. Magnesium: its role in nutrition and carcinogenesis.

    PubMed

    Blaszczyk, Urszula; Duda-Chodak, Aleksandra

    2013-01-01

    Magnesium (Mg2+) plays a key role in many essential cellular processes such as intermediary metabolism, DNA replication and repair, transporting potassium and calcium ions, cell proliferation together with signalling transduction. Dietary sources rich in magnesium are whole and unrefined grains, seeds, cocoa, nuts, almonds and green leafy vegetables. Hard water is also considered to be an important source of magnesium beneficial to human health. The daily dietary intake of magnesium is however frequently found to be below that recommended in Western countries. Indeed, it is recognised that magnesium deficiency may lead to many disorders of the human body, where for instance magnesium depletion is believed to play an important role in the aetiology of the following; cardiovascular disease (including thrombosis, atherosclerosis, ishaemic heart disease, myocardial infarction, hypertension, arrhythmias and congestive heart failure in human), as well as diabetes mellitus, gastrointestinal (GI) tract disease, liver cirrhosis and diseases of the thyroid and parathyroid glands. Insufficient dietary intake of magnesium may also significantly affect the development and exacerbation ofADHD (Attention Deficit- Hyperactivity Disorder) symptoms in children. The known links between magnesium and carcinogenesis still remain unclear and complex, with conflicting results being reported from many experimental, epidemiological and clinical studies; further knowledge is thus required. Mg2+ ions are enzyme cofactors involved in DNA repair mechanisms that maintain genomic stability and fidelity. Any magnesium deficiencies could thereby cause a dysfunction of these systems to occur leading to DNA mutations. Magnesium deficiency may also be associated with inflammation and increased levels of free radicals where both inflammatory mediators and free radicals so arising could cause oxidative DNA damage and therefore tumour formation. The presented review article now provides a summary

  9. Magnesium in disease: a review with special emphasis on the serum ionized magnesium.

    PubMed

    Sanders, G T; Huijgen, H J; Sanders, R

    1999-01-01

    This review deals with the six main clinical situations related to magnesium or one of its fractions, including ionized magnesium: renal disease, hypertension, pre-eclampsia, diabetes mellitus, cardiac disease, and the administration of therapeutic drugs. Issues addressed are the physiological role of magnesium, eventual changes in its levels, and how these best can be monitored. In renal disease mostly moderate hypermagnesemia is seen; measuring ionized magnesium offers minimal advantage. In hypertension magnesium might be lowered but its measurement does not seem relevant. In the prediction of severe pre-eclampsia, elevated ionized magnesium concentration may play a role, but no unequivocal picture emerges. Low magnesium in blood may be cause for, or consequence of, diabetes mellitus. No special fraction clearly indicates magnesium deficiency leading to insulin resistance. Cardiac diseases are related to diminished magnesium levels. During myocardial infarction, serum magnesium drops. Total magnesium concentration in cardiac cells can be predicted from levels in sublingual or skeletal muscle cells. Most therapeutic drugs (diuretics, chemotherapeutics, immunosuppressive agents, antibiotics) cause hypomagnesemia due to increased urinary loss. It is concluded that most of the clinical situations studied show hypomagnesemia due to renal loss, with exception of renal disease. Keeping in mind that only 1% of the total body magnesium pool is extracellular, no simple measurement of the real intracellular situation has emerged; measuring ionized magnesium in serum has little added value at present.

  10. Observation of the 3n Evaporation Channel in the Complete Hot-Fusion Reaction {sup 26}Mg+{sup 248}Cm Leading to the New Superheavy Nuclide {sup 271}Hs

    SciTech Connect

    Dvorak, J.; Dvorakova, Z.; Kruecken, R.; Nebel, F.; Perego, R.; Schuber, R.; Tuerler, A.; Wierczinski, B.; Yakushev, A.; Bruechle, W.; Jaeger, E.; Schaedel, M.; Schausten, B.; Schimpf, E.; Chelnokov, M.; Kuznetsov, A.; Yeremin, A.; Duellmann, Ch. E.; Eberhardt, K.; Nagame, Y.

    2008-04-04

    The analysis of a large body of heavy ion fusion reaction data with medium-heavy projectiles (6{<=}Z{<=}18) and actinide targets suggests a disappearance of the 3n exit channel with increasing atomic number of the projectile. Here, we report a measurement of the excitation function of the reaction {sup 248}Cm({sup 26}Mg,xn){sup 274-x}Hs and the observation of the new nuclide {sup 271}Hs produced in the 3n evaporation channel at a beam energy well below the Bass fusion barrier with a cross section comparable to the maxima of the 4n and 5n channels. This indicates the possible discovery of new neutron-rich transactinide nuclei using relatively light heavy ion beams of the most neutron-rich stable isotopes and actinide targets.

  11. Magnesium-based implants: a mini-review.

    PubMed

    Luthringer, Bérengère J C; Feyerabend, Frank; Willumeit-Römer, Regine

    2014-01-01

    The goal of this review is to bring to the attention of the readership of Magnesium Research another facet of the importance of magnesium, i.e. magnesium-based biomaterials. A concise history of biomaterials and magnesium are thus presented. In addition, historical and current, clinical magnesium-based applications are presented.

  12. Predicting effects on oxaliplatin clearance: in vitro, kinetic and clinical studies of calcium- and magnesium-mediated oxaliplatin degradation.

    PubMed

    Han, Catherine H; Khwaounjoo, Prashannata; Hill, Andrew G; Miskelly, Gordon M; McKeage, Mark J

    2017-06-22

    This study evaluated the impact of calcium and magnesium on the in vitro degradation and in vivo clearance of oxaliplatin. Intact oxaliplatin and Pt(DACH)Cl2 were measured in incubation solutions by HPLC-UV. A clinical study determined changes in plasma concentrations of calcium and magnesium in cancer patients and their impact on oxaliplatin clearance. Kinetic analyses modelled oxaliplatin degradation reactions in vitro and contributions to oxaliplatin clearance in vivo. Calcium and magnesium accelerated oxaliplatin degradation to Pt(DACH)Cl2 in chloride-containing solutions in vitro. Kinetic models based on calcium and magnesium binding to a monochloro-monooxalato ring-opened anionic oxaliplatin intermediate fitted the in vitro degradation time-course data. In cancer patients, calcium and magnesium plasma concentrations varied and were increased by giving calcium gluconate and magnesium sulfate infusions, but did not alter or correlate with oxaliplatin clearance. The intrinsic in vitro clearance of oxaliplatin attributed to chloride-, calcium- and magnesium-mediated degradation predicted contributions of <2.5% to the total in vivo clearance of oxaliplatin. In conclusion, calcium and magnesium accelerate the in vitro degradation of oxaliplatin by binding to a monochloro-monooxalato ring-opened anionic intermediate. Kinetic analysis of in vitro oxaliplatin stability data can be used for in vitro prediction of potential effects on oxaliplatin clearance in vivo.

  13. Method for magnesium sulfate recovery

    DOEpatents

    Gay, Richard L.; Grantham, LeRoy F.

    1987-01-01

    A method of obtaining magnesium sulfate 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 then contacted with a concentrated sulfuric acid under certain prescribed conditions to produce a liquid product and a solid product. The particulate solid product and a minor amount of the liquid is then treated to produce a solid residue consisting essentially of magnesium sulfate substantially free of uranium and having a residual radioactivity level of less than 1000 pCi/gm. In accordance with the preferred embodiment of the invention, a catalyst and an oxidizing agent are used during the initial acid treatment and a final solid residue has a radioactivity level of less than about 50 pCi/gm.

  14. Method for magnesium sulfate recovery

    DOEpatents

    Gay, R.L.; Grantham, L.F.

    1987-08-25

    A method is described for obtaining magnesium sulfate substantially free from radioactive uranium from a slag containing the same and having a radioactivity level of at least about 7,000 pCi/gm. The slag is ground to a particle size of about 200 microns or less. The ground slag is then contacted with a concentrated sulfuric acid under certain prescribed conditions to produce a liquid product and a solid product. The particulate solid product and a minor amount of the liquid is then treated to produce a solid residue consisting essentially of magnesium sulfate substantially free of uranium and having a residual radioactivity level of less than 1,000 pCi/gm. In accordance with the preferred embodiment of the invention, a catalyst and an oxidizing agent are used during the initial acid treatment and a final solid residue has a radioactivity level of less than about 50 pCi/gm.

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

    DOEpatents

    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.

  16. Microstructural Effects on the Spall Properties of ECAE Magnesium and Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Williams, Cyril

    2015-06-01

    Magnesium and magnesium alloys are light weight materials and hence, are being increasingly employed as light armor in military applications. However, because of its limited slip systems (HCP) magnesium and magnesium alloys are relatively brittle as compared to FCC and BCC lattice structures. For this study, the effects of microstructure on the spall properties of magnesium and magnesium alloys processed using Equi-Channel Angular Extrusion (ECAE) were investigated using a 51 mm and 105 mm bore gas guns. Symmetric spall and recovery plate impact experiments were performed at impact velocities ranging from approximately 100 m/s and 400 m/s. Free surface velocity profiles of the shocked samples were obtained using Photonic Doppler Velocimetry (PDV). The spall strength and Hugoniot Elastic Limit (HEL) were extracted from the free surface velocity profiles. In addition, the microstructures of the pre-shocked and post-shocked magnesium and magnesium alloys were acquired using Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM).

  17. Synthesis of rutherfordium isotopes in the 238U(26Mg, xn)264-xRf reaction and study of their decay properties

    SciTech Connect

    Gates, Jacklyn M; Gates, J.M.; Garcia, M.A.; Gregorich, K.E.; Dullmann, Ch.E.; Dragojevic, I.; Dvorak, J.; Eichler, R.; Folden III, C.M.; Loveland, W.; Nelson, S.L.; Pang, G.K.; Stavsetra, L.; Sudowe, R.; Turler, A.; Nitsche, H.

    2008-01-15

    Isotopes of rutherfordium (258-261Rf) were produced in irradiations of 238U targets with 26Mg beams. Excitation functions were measured for the 4n, 5n and 6n exit channels. Production of 261Rf in the 3n exit channel with a cross section of 28+92-26 pb was observed. Alpha decay of 258Rf was observed for the first time with an alpha-particle energy of 9.05+-0.03 MeV and an alpha/total decay branching ratio of 0.31+-0.11. In 259Rf, the electron capture/total decay branching ratio was measured to be 0.15+-0.04. The measured half-lives for 258Rf, 259Rf and 260Rf were 14.7+1.2-1.0 ms, 2.5+0.4-0.3 s and 22.2+3.0-2.4 ms, respectively, in agreement with literature data. The systematics of the alpha decay Q values and of the partial spontaneous fission half-lives were evaluated for even-even nuclides in the region of the N = 152, Z = 100 deformed shell. The influence of the N = 152 shell on the alpha decay Q values for rutherfordium was observed to be similar to that of the lighter elements (96<_ Z<_ 102). However, the N = 152 shell does not stabilize the rutherfordium isotopes against spontaneous fission, as it does in the lighter elements (96<_ Z<_102).

  18. Catalysts comprising magnesium and a transition metal

    SciTech Connect

    Bujadoux, K.

    1984-10-09

    A catalyst comprising the product obtained by bringing into contact a compound of magnesium comprising at least one species selected from the group consisting of magnesium monohalides (MgX), halo-magnesium hydrides (HMgX) and magnesium hydride (MgH/sub 2/), X being a halogen and the said species MgX or HMgX being obtained by thermal decomposition of a powdery organo-magnesium halide R/sub 1/MgX wherein R/sub 1/ is an organic radical; and at least one halide of a transistion metal selected from the group consisting of titanium and vanadium, the valency of said metal in said halide being lower than or equal to 3, the quantities being such that the atomic ratio of magnesium to said transistion metal is between 1 and 25, and a catalyst system including the catalyst that is suitable for use in the polymerization of olefins and particularly ethylene.

  19. Lightweight Heat Pipes Made from Magnesium

    NASA Technical Reports Server (NTRS)

    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.

  20. Magnesium alloy applications in automotive structures

    NASA Astrophysics Data System (ADS)

    Easton, Mark; Beer, Aiden; Barnett, Matthew; Davies, Chris; Dunlop, Gordon; Durandet, Yvonne; Blacket, Stuart; Hilditch, Tim; Beggs, Peter

    2008-11-01

    The use of magnesium alloys in structural applications has great potential for the lightweighting of transportation vehicles. Research within the CAST Cooperative Research Centre has tackled some of the important issues related to the use of magnesium in structural applications. To this end, a new alloy with extrudability and properties similar to 6000 series aluminum alloys has been developed. Furthermore, a method of laser heating magnesium alloys before self-piercing riveting has enabled high-integrity joining between magnesium components or between magnesium and dissimilar metals. In this paper, new technologies and improved understanding of the deformation behavior of wrought magnesium alloys are discussed in light of key metallurgical features such as alloy composition, grain size, and work hardening rate.

  1. Magnesium isotopic heterogeneity across the cratonic lithosphere in eastern China and its origins

    NASA Astrophysics Data System (ADS)

    Wang, Ze-Zhou; Liu, Sheng-Ao; Ke, Shan; Liu, Yi-Can; Li, Shu-Guang

    2016-10-01

    Available data in the literature have demonstrated a broad magnesium (Mg) isotope range for mantle and lower continental crustal rocks, implying an isotopically heterogeneous continental lithosphere, but its origin has not been thoroughly understood. Here, to investigate the primary cause of lithospheric Mg isotopic heterogeneity, we report major-trace elements, Sr and Mg isotope data for thirty deep-seated mafic xenoliths, which sampled different lithospheric depths in the southeastern North China Craton (NCC). The xenoliths are classified into three types based upon petrology and mineralogy, sampling from middle continental crust (Group I), lower continental crust (Group II) and lithospheric mantle (Group III), respectively. The Group I xenoliths have mantle-like to slightly high δ26Mg values (- 0.32 ‰ to + 0.01 ‰), whereas some of the Group II xenoliths have very low δ26Mg values (- 0.93 ‰ to - 0.07 ‰), reflecting substantial reaction with intracrustal carbonate-derived fluids. Combined with data in the literature, the results suggest that the Mg isotopic composition of the lower continental crust is much more heterogeneous and lighter on average relative to the middle continental crust. Except for one sample, the Group III xenoliths have extremely low δ26Mg values (- 1.23 ‰ to - 0.73 ‰), the lightest among values already reported for mantle-derived rocks including peridotites and basalts. They also have highly variable 87Sr/86Sr ratios, of 0.70387 to 0.71675. The covariation of Mg and Sr isotopes in Group III xenoliths can be explained by Mg and Sr isotopic exchange reactions during mantle metasomatism, implying that the sub-continental mantle has been significantly modified by fluids derived from recycled carbonate-pelite bearing oceanic crust. Together with the metasomatism age of ∼400 Ma obtained for one Group III xenolith, the results provide new evidence for the presence of extremely low-δ26Mg rocks in the lithosphere and indicate ancient

  2. IMPROVED MAGNESIUM OXIDE SLIP CASTING METHOD

    DOEpatents

    Stoddard, S.D.; Nuckolls, D.E.

    1963-12-31

    A process for making an aqueous magnesium oxide slip casting slurry comprising the steps of mixing finely ground fused magnesium oxide with water, milling the slurry for at least 30 hours at a temperature of 2-10 deg C (the low temperature during milling inhibiting the formation of hydrated magnesium oxide), discharging the slurry from the mill, adding hydrochloric acid as a deflocculent, and adding a scum inhibitor is presented. (AEC)

  3. Nanotechnology Corrosion Pretreatment for Magnesium Alloys

    DTIC Science & Technology

    2012-08-29

    Pretreatment for Magnesium Alloys AMS-SAE-M-3171, Type IV Replacement on AZ91D Glycolic Nitrate Pickle (GNP) (1 min) PT-60 (3 min) 0 hr SST 1 4 3 2...Nanotechnology Corrosion Pretreatment for Magnesium Alloys Mr. Jules F. Senske and Mr. Daniel Schmidt Army Research Development and...SUBTITLE Nanotechnology Corrosion Pretreatment for Magnesium Alloys 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d

  4. Magnesium deficiency in a medical ICU population.

    PubMed

    Ryzen, E; Wagers, P W; Singer, F R; Rude, R K

    1985-01-01

    The serum magnesium level was measured in 94 consecutive patients admitted to the medical ICU of Los Angeles County/University of Southern California Medical Center over a 2-month period. Sixty-five percent of patients with serum creatinine concentrations of 1.1 mg/dl or less were hypomagnesemic. Of these, one third had hypocalcemia that was corrected with magnesium supplementation. Physicians should be alert to the high incidence of magnesium deficiency in critically ill patients.

  5. Crystal structure of a dimeric β-diketiminate magnesium complex

    PubMed Central

    MacNeil, Connor S.; Johnson, Kevin R. D.; Hayes, Paul G.; Boeré, René T.

    2016-01-01

    The solid-state structure of a dimeric β-diketiminate magnesium(II) complex is discussed. The compound, di-μ-iodido-bis­[(­{4-amino-1,5-bis­[2,6-bis­(propan-2-yl)phen­yl]pent-3-en-2-yl­idene}aza­nido-κ2 N,N′)magnesium(II)] toluene sesquisolvate, [Mg2(C29H41N2)2I2]·1.5C7H8, crystallizes as two independent mol­ecules, each with 2/m crystallographic site symmetry, located at Wyckoff sites 2c and 2d. These have symmetry-equivalent magnesium atoms bridged by μ-iodide ligands with very similar Mg—I distances. The two Mg atoms are located slightly below (∼0.5 Å) the least-squares plane defined by N–C—C–N atoms in the ligand scaffold, and are approximately tetra­hedrally coordinated. One and one-half toluene solvent mol­ecules are disordered with respect to mirror-site symmetry at Wyckoff sites 4i and 2a, respectively. In the former case, two toluene mol­ecules inter­act in an off-center parallel stacking arrangement; the shortest C to C′ (π–π) distance of 3.72 (1) Å was measured for this inter­action. PMID:27980823

  6. Analysis of Different Inhibitors for Magnesium Investment Casting

    NASA Astrophysics Data System (ADS)

    Herrero-Dorca, N.; Sarriegi Etxeberria, H.; Hurtado, I.; Andres, U.; Rodriguez, P.; Arruebarrena, G.

    2012-01-01

    Investment casting of magnesium is a well suited process for the production of aeronautic and automotive components. But still, this process has not been properly developed. One reason for that are the reactions between the Mg melt and the ceramics of the mould that produce a non-desired oxide layer on the part surface. These reactions can be inhibited by the use of silica-free slurries with a higher stability than conventional ones. Another way is using inhibitors, chemical compounds based in fluorides that react with the melt, creating a protective surface layer in the casting. With the aim of developing a reaction-free process, alumina moulds with a stepped geometry have been constructed. These provide different interface conditions. Conventional SF6, non-conventional KBF4 and NaBF4 and environmentally friendly FK inhibitors have been tested on. As a result, KBF4 has been identified as the most suitable inhibitor for magnesium investment casting. Furthermore, the analysis of the cooling curve of different interfaces has provided essential information about the reaction mechanism of the inhibitors.

  7. Easy access to nucleophilic boron through diborane to magnesium boryl metathesis

    NASA Astrophysics Data System (ADS)

    Pécharman, Anne-Frédérique; Colebatch, Annie L.; Hill, Michael S.; McMullin, Claire L.; Mahon, Mary F.; Weetman, Catherine

    2017-04-01

    Organoboranes are some of the most synthetically valuable and widely used intermediates in organic and pharmaceutical chemistry. Their synthesis, however, is limited by the behaviour of common boron starting materials as archetypal Lewis acids such that common routes to organoboranes rely on the reactivity of boron as an electrophile. While the realization of convenient sources of nucleophilic boryl anions would open up a wealth of opportunity for the development of new routes to organoboranes, the synthesis of current candidates is generally limited by a need for highly reducing reaction conditions. Here, we report a simple synthesis of a magnesium boryl through the heterolytic activation of the B-B bond of bis(pinacolato)diboron, which is achieved by treatment of an easily generated magnesium diboranate complex with 4-dimethylaminopyridine. The magnesium boryl is shown to act as an unambiguous nucleophile through its reactions with iodomethane, benzophenone and N,N'-di-isopropyl carbodiimide and by density functional theory.

  8. Lewis Acid-free and Phenolate-based Magnesium Electrolyte for Rechargeable Magnesium Batteries

    SciTech Connect

    Pan, Baofei; Zhang, Junjie; Huang, Jinhua; Vaughey, John T.; Zhang, Lu; Han, Sang Don; Zhang, Zhengcheng; Liao, Chen

    2015-03-02

    A novel Lewis acid-free and phenolate-based magnesium electrolyte has been established. The excellent reversibility and stability of this electrolyte in battery cycling render this novel Lewis acid-free synthetic approach as a highly promising alternative for the development of highly anodically stable magnesium electrolytes for rechargeable magnesium batteries.

  9. 21 CFR 862.1495 - Magnesium test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... magnesium levels in serum and plasma. Magnesium measurements are used in the diagnosis and treatment of hypomagnesemia (abnormally low plasma levels of magnesium) and hypermagnesemia (abnormally high plasma levels of...

  10. 21 CFR 862.1495 - Magnesium test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... magnesium levels in serum and plasma. Magnesium measurements are used in the diagnosis and treatment of hypomagnesemia (abnormally low plasma levels of magnesium) and hypermagnesemia (abnormally high plasma levels...

  11. 21 CFR 862.1495 - Magnesium test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... magnesium levels in serum and plasma. Magnesium measurements are used in the diagnosis and treatment of hypomagnesemia (abnormally low plasma levels of magnesium) and hypermagnesemia (abnormally high plasma levels of...

  12. 21 CFR 862.1495 - Magnesium test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... magnesium levels in serum and plasma. Magnesium measurements are used in the diagnosis and treatment of hypomagnesemia (abnormally low plasma levels of magnesium) and hypermagnesemia (abnormally high plasma levels of...

  13. 21 CFR 862.1495 - Magnesium test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... magnesium levels in serum and plasma. Magnesium measurements are used in the diagnosis and treatment of hypomagnesemia (abnormally low plasma levels of magnesium) and hypermagnesemia (abnormally high plasma levels of...

  14. A facile magnesium-containing calcium carbonate biomaterial as potential bone graft.

    PubMed

    He, Fupo; Zhang, Jing; Tian, Xiumei; Wu, Shanghua; Chen, Xiaoming

    2015-12-01

    The calcium carbonate is the main composition of coral which has been widely used as bone graft in clinic. Herein, we readily prepared novel magnesium-containing calcium carbonate biomaterials (MCCs) under the low-temperature conditions based on the dissolution-recrystallization reaction between unstable amorphous calcium carbonate (ACC) and metastable vaterite-type calcium carbonate with water involved. The content of magnesium in MCCs was tailored by adjusting the proportion of ACC starting material that was prepared using magnesium as stabilizer. The phase composition of MCCs with various amounts of magnesium was composed of one, two or three kinds of calcium carbonates (calcite, aragonite, and/or magnesian calcite). The different MCCs differed in topography. The in vitro degradation of MCCs accelerated with increasing amount of introduced magnesium. The MCCs with a certain amount of magnesium not only acquired higher compressive strength, but also promoted in vitro cell proliferation and osteogenic differentiation. Taken together, the facile MCCs shed light on their potential as bone graft. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. A study of degradation resistance and cytocompatibility of super-hydrophobic coating on magnesium.

    PubMed

    Zhang, Yufen; Feyerabend, Frank; Tang, Shawei; Hu, Jin; Lu, Xiaopeng; Blawert, Carsten; Lin, Tiegui

    2017-09-01

    Calcium stearate based super-hydrophobic coating was deposited on plasma electrolytic oxidation (PEO) pre-treated magnesium substrate. The pre-treated magnesium and super-hydrophobic coating covered sample were characterized by scanning electron microscopy, X-ray diffraction and electrochemical corrosion measurements. The cytocompatibility and degradation resistance of magnesium, pre-treated magnesium and super-hydrophobic coating were analysed in terms of cell adhesion and osteoblast differentiation. The results indicate that the calcium stearate top coating shows super-hydrophobicity and that the surface is composed of micro/nanostructure. The super-hydrophobic coating covered sample shows higher barrier properties compared with the PEO pre-treated magnesium and bare magnesium. Human osteoblast proliferation, but not differentiation is enhanced by the PEO coating. Contrary, the super-hydrophobic coating reduces proliferation, but enhances differentiation of osteoblast, observable by the formation of hydroxyapatite. The combination of corrosion protection and cell reaction indicates that this system could be interesting for biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Influence of Maillard products from bread crust on magnesium bioavailability in rats.

    PubMed

    Roncero-Ramos, Irene; Delgado-Andrade, Cristina; Morales, Francisco J; Navarro, María Pilar

    2013-06-01

    Consumption of Maillard reaction products (MRPs) present in food has been related to deterioration of protein digestibility and changes in mineral bioavailability. We aimed to investigate the effects of MRP intake from bread crust on magnesium balance and tissue distribution, seeking causative factors among its different components. During the final stage of the trial, magnesium digestibility improved by around 15% in rats fed diets containing bread crust or its derivatives compared with the control diet. Despite certain enhancements in magnesium bioavailability in this stage, for the experimental period as a whole, this parameter remained unchanged. However, specific changes in the content and/or concentration in some organs were observed, particularly in the femur, where magnesium levels were higher due to the smaller size of the bones. Consumption of MRPs from bread crust or its different components did not modify the magnesium balance. Nevertheless, the bread crust fractions led to some changes in magnesium tissue distribution which did not match the effects induced by complete bread crust intake, suggesting the importance of designing studies with real-food systems, in order to reinforce the validity of the findings obtained. © 2012 Society of Chemical Industry.

  17. Magnesium enrichment and distribution in plants.

    PubMed

    Courtois, D; Kastenmayer, P; Clough, J; Vigo, M; Sabatier, M; Arnaud, M J

    2003-12-01

    Food products enriched with stable isotopes are used in nutrition to study the metabolic fate of nutrients in humans. This study reports on the labeling of green beans, white beans, soybeans and wheat with a stable isotope of magnesium (25Mg) obtained in greenhouse conditions for further studies on magnesium bioavailability. Soybean and green bean are the most efficient plant species to obtain large amounts of edible parts rapidly with a minimum loss of labeled Mg in other parts of the plants. The results obtained showed that a relatively high percentage of the magnesium found in seeds (grains/beans) can come from the redistribution of magnesium previously accumulated in other organs.

  18. Wide Strip Casting Technology of Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Park, W.-J.; Kim, J. J.; Kim, I. J.; Choo, D.

    Extensive investigations relating to the production of high performance and low cost magnesium sheet by strip casting have been performed for the application to automotive parts and electronic devices. Research on magnesium sheet production technology started in 2004 by Research Institute of Industrial Science and Technology (RIST) with support of Pohang Iron and Steel Company (POSCO). POSCO has completed the world's first plant to manufacture magnesium coil. Another big project in order to develop wide strip casting technology for the automotive applications of magnesium sheets was started in succession.

  19. Evidence for bicarbonate-dependent magnesium reabsorption.

    PubMed

    Hartmann, A; Langberg, H; Dibona, G; Kiil, F

    1983-01-01

    During ethacrynic acid administration about 50% of the filtered load of magnesium is reabsorbed. To examine whether the remaining component of magnesium reabsorption is bicarbonate-dependent, i.e. varies with factors known to alter passive reabsorption, experiments were performed in anesthetized dogs. During ethacrynic acid administration MgCl2 infusion raised the plasma concentration of magnesium (PMg) from 0.64 +/- 0.05 to 3.06 +/- 0.27 mM and doubled magnesium reabsorption. The infusion of acetazolamide at high PMg reduced bicarbonate reabsorption by 41 +/- 3% and magnesium reabsorption by 31 +/- 16%. When plasma pH was reduced to 7.04 +/- 0.02 and increased to 7.83 +/- 0.02 by altering PCO2 at a constant plasma bicarbonate concentration of 31.2 +/- 0.8 mM, magnesium and bicarbonate reabsorption were correlated (r = 0.82). The infusion of mannitol, which acts by reducing passive solute transport without affecting bicarbonate reabsorption, halved magnesium reabsorption. By combining mannitol and acetazolamide infusions, only 6 +/- 4% of the filtered magnesium was still reabsorbed. These results indicate that the reabsorption of magnesium remaining after the infusion of ethacrynic acid and after raising PMg varies with changes in PCO2 and is inhibited by the infusion of acetazolamide and mannitol as expected for bicarbonate-dependent passive reabsorption.

  20. A randomised controlled trial comparing rocuronium priming, magnesium pre-treatment and a combination of the two methods.

    PubMed

    Kim, M H; Oh, A Y; Jeon, Y T; Hwang, J W; Do, S H

    2012-07-01

    We investigated whether magnesium sulphate combined with rocuronium priming shortens the onset of neuromuscular blockade, compared with these methods used alone. Ninety-two patients scheduled for general anaesthesia were randomly allocated to one of four groups: controls were given 0.6 mg.kg(-1) rocuronium; patients in the prime group were given 0.06 mg.kg(-1) rocuronium three minutes before a further dose of 0.54 mg.kg(-1) rocuronium; patients in the magnesium group were given an infusion of 50 mg.kg(-1) magnesium sulphate before rocuronium and patients in the magnesium and prime group were given both the magnesium sulphate and the priming dose of rocuronium. Tracheal intubation was attempted 40 s after the rocuronium injection. The time to onset of neuromuscular blockade was the primary outcome; duration of blockade and tracheal intubating conditions were also measured. The group allocation and study drugs were coded and concealed until statistical analyses were completed. The magnesium and prime group had the shortest mean (SD) onset time (55 (16)s; p < 0.001), and best tracheal intubating conditions (p < 0.05). No statistical difference was found for the duration of blockade. As for adverse events, a burning or heat sensation was reported in eight (35%) and six (26%) patients in the magnesium and magnesium and prime groups, respectively. The combination of magnesium sulphate and rocuronium priming accelerated the onset or neuromuscular blockade and improved rapid-sequence intubating conditions, compared with either magnesium sulphate or priming used alone. Anaesthesia © 2012 The Association of Anaesthetists of Great Britain and Ireland.

  1. Magnesium isotope systematics in Martian meteorites

    NASA Astrophysics Data System (ADS)

    Magna, Tomáš; Hu, Yan; Teng, Fang-Zhen; Mezger, Klaus

    2017-09-01

    Magnesium isotope compositions are reported for a suite of Martian meteorites that span the range of petrological and geochemical types recognized to date for Mars, including crustal breccia Northwest Africa (NWA) 7034. The δ26Mg values (per mil units relative to DSM-3 reference material) range from -0.32 to -0.11‰; basaltic shergottites and nakhlites lie to the heavier end of the Mg isotope range whereas olivine-phyric, olivine-orthopyroxene-phyric and lherzolitic shergottites, and chassignites have slightly lighter Mg isotope compositions, attesting to modest correlation of Mg isotopes and petrology of the samples. Slightly heavier Mg isotope compositions found for surface-related materials (NWA 7034, black glass fraction of the Tissint shergottite fall; δ26Mg > -0.17‰) indicate measurable Mg isotope difference between the Martian mantle and crust but the true extent of Mg isotope fractionation for Martian surface materials remains unconstrained. The range of δ26Mg values from -0.19 to -0.11‰ in nakhlites is most likely due to accumulation of clinopyroxene during petrogenesis rather than garnet fractionation in the source or assimilation of surface material modified at low temperatures. The rather restricted range in Mg isotope compositions between spatially and temporally distinct mantle-derived samples supports the idea of inefficient/absent major tectonic cycles on Mars, which would include plate tectonics and large-scale recycling of isotopically fractionated surface materials back into the Martian mantle. The cumulative δ26Mg value of Martian samples, which are not influenced by late-stage alteration processes and/or crust-mantle interactions, is - 0.271 ± 0.040 ‰ (2SD) and is considered to reflect δ26Mg value of the Bulk Silicate Mars. This value is robust taking into account the range of lithologies involved in this estimate. It also attests to the lack of the Mg isotope variability reported for the inner Solar System bodies at current

  2. On the role of magnesium and silicon in the formation of alumina from aluminum alloys by means of DIMOX processing

    SciTech Connect

    Yang, L.; Zhu, D.; Xu, C.; Zhang, J.; Zhang, J.

    1996-08-01

    This article deals with the reaction mechanisms of the DIMOX (Directed Melt Oxided) processing of aluminum alloys. An orthogonalized experimental procedure was introduced to stipulate the effects of the reaction temperature, reaction time, and additional metallic elements, magnesium and silicon, on the oxidation process of aluminum alloys. Emphasis is placed on the distribution of magnesium and silicon in the products so that the behaviors of these two crucial elements for the formation of alumina from directed oxidation of aluminum alloys could be revealed. Alterative methods, including optical and scanning electron microscopy (SEM), electron probing, and wave spectrum analysis were applied to specify the microstructure characters of the products and locate the position of both magnesium and silicon in the reaction products. Judged by the weight gain after reaction, the results indicated that the temperature is the most influential factor in controlling the oxidation kinetics. Both magnesium and silicon are rather concentrated in specific regions than homogeneously distributed in the whole products. The contents of magnesium and silicon in the surface region are not as high as expected, and most of the magnesium being concentrated in the region directly neighboring the bulky metals and most of the Si in the residual bulky metals, although the contents of these two elements in the surface region are a little higher than the regions next to the surface. These characteristics, combined with other investigations, suggest that the decisive role of the slight amount of magnesium and silicon in the nucleation and growth of Al{sub 2}O{sub 3} could be explained by the proposed circulated reaction.

  3. Interdiffusion of magnesium and iron dopants in gallium nitride

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Tomonobu; Kitatani, Takeshi; Terano, Akihisa; Mochizuki, Kazuhiro

    2015-03-01

    The interdiffusion of magnesium and iron in gallium nitride (GaN), i.e., magnesium-iron interdiffusion, was investigated using magnesium-doped GaN layers on iron-doped GaN substrates. The investigation confirms that the magnesium-iron interdiffusion strongly depends on the concentrations of magnesium and iron, that is, it occurs when the iron and magnesium concentrations are high (magnesium: 2 × 1020 cm-3 iron: 2 × 1019 cm-3). It also confirms that diffused iron in the magnesium-doped GaN layer acts as a nonradiative recombination center in GaN.

  4. Addressing fluorogenic real-time qPCR inhibition using the novel custom Excel file system 'FocusField2-6GallupqPCRSet-upTool-001' to attain consistently high fidelity qPCR reactions

    PubMed Central

    Ackermann, Mark R.

    2006-01-01

    The purpose of this manuscript is to discuss fluorogenic real-time quantitative polymerase chain reaction (qPCR) inhibition and to introduce/define a novel Microsoft Excel-based file system which provides a way to detect and avoid inhibition, and enables investigators to consistently design dynamically-sound, truly LOG-linear qPCR reactions very quickly. The qPCR problems this invention solves are universal to all qPCR reactions, and it performs all necessary qPCR set-up calculations in about 52 seconds (using a pentium 4 processor) for up to seven qPCR targets and seventy-two samples at a time – calculations that commonly take capable investigators days to finish. We have named this custom Excel-based file system "FocusField2-6GallupqPCRSet-upTool-001" (FF2-6-001 qPCR set-up tool), and are in the process of transforming it into professional qPCR set-up software to be made available in 2007. The current prototype is already fully functional. PMID:17033699

  5. Mono-BHT heteroleptic magnesium complexes: synthesis, molecular structure and catalytic behavior in the ring-opening polymerization of cyclic esters.

    PubMed

    Nifant'ev, I E; Shlyakhtin, A V; Bagrov, V V; Minyaev, M E; Churakov, A V; Karchevsky, S G; Birin, K P; Ivchenko, P V

    2017-09-28

    Numerous heteroleptic 2,6-di-tert-butyl-4-methylphenolate (BHT) magnesium complexes have been synthesized by treatment of (BHT)MgBu(THF)2 with various alcohols. Molecular structures of the complexes have been determined by X-ray diffraction. The magnesium coordination number in [(BHT)Mg(μ-OBn)(THF)]2 (3) and [(BHT)Mg(μ-O-tert-BuC6H4)(THF)]2 (4) is equal to 4. Complexes formed from esters of glycolic and lactic acids, [(BHT)Mg(μ-OCH2COOEt)(THF)]2 (5) and [(BHT)Mg(μ-OCH(CH3)COOCH2COO(t)Bu)(THF)]2 (6) contain chelate fragments with pentacoordinated magnesium. Compounds 3-6 contain THF molecules coordinated to magnesium atoms. Complex {(BHT)Mg[μ-O(CH2)3CON(CH3)2]}2 (7) does not demonstrate any tendency to form an adduct with THF. It has been experimentally determined that complexes 3 and 5 are highly active catalysts of lactide polymerization. The activity of 4 is rather low, and complex 7 demonstrates moderate productivity. According to DOSY NMR experiments, compounds 3 and 5 retain their dimeric structures even in THF. The free energies of model dimeric [(DBP)Mg(μ-OMe)(Sub)]2 and monomeric (DBP)Mg(OMe)(Sub)2 products on treatment of [(DBP)Mg(μ-OMe)(THF)]2 with a series of σ-electron donors (Sub) have been estimated by DFT calculations. These results demonstrate that the substitution of THF by Sub in a dimeric molecule is an energetically allowed process, whereas the dissociation of dimers is energetically unfavorable. DFT modeling of ε-CL and (dl)-lactide ROP catalyzed by dimeric and monomeric complexes showed that a cooperative effect of two magnesium atoms occurs within the ROP for binuclear catalytic species. A comparison of the reaction profiles for ROP catalyzed by binuclear and mononuclear species allowed us to conclude that the binuclear mechanism is favorable in early stages of ROP initiated by dimers 3 and 5.

  6. The TMS Magnesium Committee: Committed to the Advancement of Global Magnesium Technology

    SciTech Connect

    Sillekens, Wim H.; Nyberg, Eric A.

    2011-04-21

    The TMS Magnesium Committee was established in the year 2000 as a spin-off of the Reactive Metals Committee, triggered by the strong global growth of magnesium being used in a variety of structural lightweight applications since the mid-1990’s. Since then the committee has seen a distinct development in terms of size, participation and focus. The article at hand outlines this development by recapitulating the output of its two main activities: the annual Magnesium Technology Symposia and the JOM Special Issues dedicated to magnesium research and development. Further records on the Magnesium Committee are available from the committee homepage (accessible through http://members.tms.org).

  7. Iatrogenic magnesium toxicity following intravenous infusion of magnesium sulfate: risks and strategies for prevention

    PubMed Central

    Cavell, Gillian F; Bryant, Catherine; Jheeta, Seetal

    2015-01-01

    A 65-year-old man being treated with radiotherapy and chemotherapy for recurrent colonic adenocarcinoma was admitted for management of hypokalaemia and hypomagnesaemia secondary to diarrhoea. He was treated with intravenous infusions of potassium chloride and magnesium sulfate. Following an infusion of magnesium sulfate, he experienced a sudden neurological deterioration. A CT of the head revealed no haemorrhage or evidence of acute ischaemic injury. Results of serum biochemistry later that day revealed an elevated magnesium level. Iatrogenic magnesium toxicity was suspected. Further discussions between the pharmacist and ward staff confirmed that a medication error had been made in the preparation of the infusion resulting in an overdose of intravenous magnesium. PMID:26231187

  8. Antimicrobial properties and dentin bonding strength of magnesium phosphate cements.

    PubMed

    Mestres, G; Abdolhosseini, M; Bowles, W; Huang, S-H; Aparicio, C; Gorr, S-U; Ginebra, M-P

    2013-09-01

    The main objective of this work was to assess the antimicrobial properties and the dentin-bonding strength of novel magnesium phosphate cements (MPC). Three formulations of MPC, consisting of magnesium oxide and a phosphate salt, NH4H2PO4, NaH2PO4 or a mixture of both, were evaluated. As a result of the setting reaction, MPC transformed into either struvite (MgNH4PO4·6H2O) when NH4H2PO4 was used or an amorphous magnesium sodium phosphate when NaH2PO4 was used. The MPC had appropriate setting times for hard tissue applications, high early compressive strengths and higher strength of bonding to dentin than commercial mineral trioxide aggregate cement. Bacteriological studies were performed with fresh and aged cements against three bacterial strains, Escherichia coli, Pseudomonas aeruginosa (planktonic and in biofilm) and Aggregatibacter actinomycetemcomitans. These bacteria have been associated with infected implants, as well as other frequent hard tissue related infections. Extracts of different compositions of MPC had bactericidal or bacteriostatic properties against the three bacterial strains tested. This was associated mainly with a synergistic effect between the high osmolarity and alkaline pH of the MPC. These intrinsic antimicrobial properties make MPC preferential candidates for applications in dentistry, such as root fillers, pulp capping agents and cavity liners.

  9. Magnesium stress signaling in plant: Just a beginning

    PubMed Central

    Guo, Wanli; Chen, Shaoning; Hussain, Nazim; Cong, Yuexi; Liang, Zongsuo; Chen, Kunming

    2015-01-01

    Magnesium (Mg) is one of the most important nutrients, involves mainly in plant growth and development. However, the signaling pathways response to magnesium stresses (MgSs) is known little, but several studies lately may improve the research development. Several phytohormones such as abscisic acid (ABA), ethylene, auxins, and their factors were found responding to MgSs, and there may be some signal pathways linking these hormones and downstream reactions together, e.g., carbon fixation and transfer, starch and sugar metabolism, ion uptaking and reactive oxygen species (ROS) increasing. Consequently, Arabidopsis morphogenesis is remodeled. In this review, we mainly discussed recent literatures involving in plant response to MgSs (Mg deficiency (MgD) and Mg toxicity (MgT)), including plant morphogenesis remodeling, magnesium transporters and signaling transductions. Moreover, the future study challenges related to the responding signalings to MgSs in plants are also presented. Regardless, the iceberg of signal transduction of MgSs in plants is appeared. PMID:25806908

  10. Hydrogen cycling of niobium and vanadium catalyzed nanostructured magnesium.

    PubMed

    Schimmel, H Gijs; Huot, Jacques; Chapon, Laurent C; Tichelaar, Frans D; Mulder, Fokko M

    2005-10-19

    The reaction of hydrogen gas with magnesium metal, which is important for hydrogen storage purposes, is enhanced significantly by the addition of catalysts such as Nb and V and by using nanostructured powders. In situ neutron diffraction on MgNb(0.05) and MgV(0.05) powders give a detailed insight on the magnesium and catalyst phases that exist during the various stages of hydrogen cycling. During the early stage of hydriding (and deuteriding), a MgH(1< x < 2) phase is observed, which does not occur in bulk MgH(2) and, thus, appears characteristic for the small particles. The abundant H vacancies will cause this phase to have a much larger hydrogen diffusion coefficient, partly explaining the enhanced kinetics of nanostructured magnesium. It is shown that under relevant experimental conditions, the niobium catalyst is present as NbH(1). Second, a hitherto unknown Mg-Nb perovskite phase could be identified that has to result from mechanical alloying of Nb and the MgO layer of the particles. Vanadium is not visible in the diffraction patterns, but electron micrographs show that the V particle size becomes very small, 2-20 nm. Nanostructuring and catalyzing the Mg enhance the adsorption speed that much that now temperature variations effectively limit the absorption speed and not, as for bulk, the slow kinetics through bulk MgH(2) layers.

  11. Regulation of Chloroplast Photosynthetic Activity by Exogenous Magnesium 1

    PubMed Central

    Huber, Steven C.

    1978-01-01

    Magnesium was most inhibitory to photosynthetic reactions by intact chloroplasts when the magnesium was added in the dark before illumination. Two millimolar MgCl2, added in the dark, inhibited CO2-dependent O2 evolution by Hordeum vulgare L. and Spinacia oleracea L. (C3 plants) chloroplasts 70 to 100% and inhibited (pyruvate + oxaloacetate)-dependent O2 evolution by Digitaria sanguinalis L. (C4 plant) mesophyll chloroplasts from 80 to 100%. When Mg2+ was added in the light, O2 evolution was reduced only slightly. O2 evolution in the presence of phosphoglycerate was less sensitive to Mg2+ inhibition than was CO2-dependent O2 evolution. Magnesium prevented the light activation of several photosynthetic enzymes. Two millimolar Mg2+ blocked the light activation of NADP-malate dehydrogenase in D. sanguinalis mesophyll chloroplasts, and the light activation of phosphoribulokinase, NADP-linked glyceraldehyde-3-phosphate dehydrogenase, and fructose 1,6-diphosphatase in barley chloroplasts. The results suggest that Mg2+ inhibits chloroplast photosynthesis by preventing the light activation of certain enzymes. PMID:16660509

  12. Reaction of 2,6-dichloroquinone-4-chloroimide (Gibbs reagent) with permethrin – an optical sensor for rapid detection of permethrin in treated wood

    PubMed Central

    2013-01-01

    Background A novel optical sensor for the rapid and direct determination of permethrin preservatives in treated wood was designed. The optical sensor was fabricated from the immobilisation of 2,6-dichloro-p-benzoquinone-4-chloroimide (Gibbs reagent) in nafion/sol–gel hybrid film and the mode of detection was based on absorption spectrophotometry. Physical entrapment was employed as a method of immobilisation. Results The sensor gave a linear response range of permethrin between 2.56–383.00 μM with detection limit of 2.5 μM and demonstrated good repeatability with relative standard deviation (RSD) for 10 μM at 5.3%, 100 μM at 2.7%, and 200 μM at 1.8%. The response time of the sensor was 40 s with an optimum response at pH 11. Conclusions The sensor was useful for rapid screening of wood or treated wood products before detailed analysis using tedious procedure is performed. The validation study of the optical sensor against standard method HPLC successfully showed that the permethrin sensor tended to overestimate the permethrin concentration determined. PMID:23867006

  13. Involvement of the antiplatelet activity of magnesium sulfate in suppression of protein kinase C and the Na+/H+ exchanger.

    PubMed

    Hsiao, George; Shen, Ming-Yi; Chou, Duen-Suey; Lin, Chien-Huang; Chen, Tzeng-Fu; Sheu, Joen-Rong

    2004-01-01

    Magnesium sulfate is widely used to prevent seizures in pregnant women with hypertension. The aim of this study was to examine the inhibitory mechanisms of magnesium sulfate in platelet aggregation in vitro. In this study, magnesium sulfate concentration-dependently (0.6-3.0 mM) inhibited platelet aggregation in human platelets stimulated by agonists. Magnesium sulfate (1.5 and 3.0 mM) also concentration-dependently inhibited phosphoinositide breakdown and intracellular Ca+2 mobilization in human platelets stimulated by thrombin. Rapid phosphorylation of a platelet protein of M(r) 47,000 (P47), a marker of protein kinase C activation, was triggered by phorbol-12-13-dibutyrate (PDBu, 50 nM). This phosphorylation was markedly inhibited by magnesium sulfate (3.0 mM). Magnesium sulfate (1.5 and 3.0 mM) further inhibited PDBu-stimulated platelet aggregation in human platelets. The thrombin-evoked increase in pHi was markedly inhibited in the presence of magnesium sulfate (3.0 mM). In conclusion, these results indicate that the antiplatelet activity of magnesium sulfate may be involved in the following two pathways: (1) Magnesium sulfate may inhibit the activation of protein kinase C, followed by inhibition of phosphoinositide breakdown and intracellular Ca+2 mobilization, thereby leading to inhibition of the phosphorylation of P47. (2) On the other hand, magnesium sulfate inhibits the Na+/H+ exchanger, leading to reduced intracellular Ca+2 mobilization, and ultimately to inhibition of platelet aggregation and the ATP-release reaction.

  14. Magnesium nitride as a convenient source of ammonia: preparation of dihydropyridines.

    PubMed

    Bridgwood, Katy L; Veitch, Gemma E; Ley, Steven V

    2008-08-21

    Magnesium nitride (Mg 3N 2) has been investigated for the preparation of dihydropyridines. This is a commercially available, bench-stable solid that generates ammonia upon treatment with protic solvents. The main features of the process are the facile reaction setup and good yields obtained in the majority of cases.

  15. Nickel/magnesium-lanthanum mixed oxide catalyst in the Kumada-coupling.

    PubMed

    Kiss, Arpád; Hell, Zoltán; Bálint, Mária

    2010-01-21

    A new, heterogeneous, magnesium-lanthanum mixed oxide solid base-supported nickel(ii) catalyst was developed. The catalyst was used successfully in the Kumada coupling of aryl halides, especially aryl bromides. The optimal reaction conditions of the coupling were determined.

  16. Discharge of a copper-magnesium galvanic cell in the presence of a weak electromagnetic field

    NASA Astrophysics Data System (ADS)

    Kolesnikov, A. A.; Zarembo, Ya. V.; Zarembo, V. I.

    2007-07-01

    The effect of weak periodic electromagnetic pulses with a repetition rate of 250 kHz on the discharge of a copper-magnesium galvanic cell is studied experimentally. Comparative characteristics of the electrochemical process and scanning electron microscopy images of electrode reaction products are presented.

  17. Summary of "Magnesium Vision 2020: A North American Automotive Strategic Vision for Magnesium"

    NASA Astrophysics Data System (ADS)

    Cole, Gerald S.

    This paper summarizes the monograph, "Magnesium Vision 2020. A North American Automotive Strategic Vision for Magnesium"1 prepared under the auspices of the United States Automotive Materials Partnership The objective was to understand the infrastructural and technical challenge that can increase the use of magnesium in the automotive industry. One hundred sixty three (163) Research and Technology Development Themes (RTDTs), or RTD projects were developed that addressed issues of corrosion, fastening, and processing-other-than-high pressure die casting to produce automotive magnesium parts. A major problem identified in the study is the limited ability of the current magnesium industrial infrastructure to supply RTD and implementation-ready automotive magnesium components. One solution is to create a magnesium cyber center wrhere globally networked experts would be able to innovate in process and product development, model metalworking and non-HPDC foundry processes, and integrate theoretical predictions/models of metallurgical structure with component function.

  18. The magnesium isotope record of cave carbonate archives

    NASA Astrophysics Data System (ADS)

    Riechelmann, S.; Buhl, D.; Schröder-Ritzrau, A.; Riechelmann, D. F. C.; Richter, D. K.; Vonhof, H. B.; Wassenburg, J. A.; Geske, A.; Spötl, C.; Immenhauser, A.

    2012-11-01

    Here we explore the potential of magnesium26Mg) isotope time-series data as continental climate proxies in speleothem calcite archives. For this purpose, a total of six Pleistocene and Holocene stalagmites from caves in Germany, Morocco and Peru and two flowstones from a cave in Austria were investigated. These caves represent the semi-arid to arid (Morocco), the warm-temperate (Germany), the equatorial-humid (Peru) and the cold-humid (Austria) climate zones. Changes in the calcite magnesium isotope signature with time are compared against carbon and oxygen isotope records from these speleothems. Similar to other proxies, the non-trivial interaction of a number of environmental, equilibrium and disequilibrium processes governs the δ26Mg fractionation in continental settings. These include the different sources of magnesium isotopes such as rainwater or snow as well as soil and host rock, soil zone biogenic activity, shifts in silicate versus carbonate weathering ratios and residence time of water in the soil and karst zone. Pleistocene stalagmites from Morocco show the lowest mean δ26Mg values (GDA: -4.26 ± 0.07‰ and HK3: -4.17 ± 0.15‰), and the data are well explained in terms of changes in aridity over time. The Pleistocene to Holocene stalagmites from Peru show the highest mean value of all stalagmites (NC-A and NC-B δ26Mg: -3.96 ± 0.04‰) but only minor variations in Mg-isotope composition, which is consistent with the rather stable equatorial climate at this site. Holocene stalagmites from Germany (AH-1 mean δ26Mg: -4.01 ± 0.07‰; BU 4 mean δ26Mg: -4.20 ± 0.10‰) suggest changes in outside air temperature was the principal driver rather than rainfall amount. The alpine Pleistocene flowstones from Austria (SPA 52: -3.00 ± 0.73‰; SPA 59: -3.70 ± 0.43‰) are affected by glacial versus interglacial climate change with outside air temperature affecting soil zone activity and weathering balance. Several δ26Mg values of the Austrian and two

  19. Synthesis and biological activity of 26-norbrassinolide, 26-norcastasterone and 26-nor-6-deoxocastasterone.

    PubMed

    Watanabe, T; Noguchi, T; Yokota, T; Shibata, K; Koshino, H; Seto, H; Kim, S; Takatsuto, S

    2001-09-01

    26-Norbrassinolide, identified as a metabolite of brassinolide in cultured cells of the liverwort, Marchantia polymorpha, as well as 26-norcastasterone and 26-nor-6-deoxocastasterone were synthesized. Synthesis of these new brassinosteroids was conducted by employing the orthoester Claisen rearrangement and asymmetric dihydroxylation as key reactions. The modified rice lamina inclination test indicated that these three 26-norbrassinosteroids were less active than their corresponding C28 brassinosteroids. Growth-promoting activities were also examined by using the brassinosteroid-deficient, dwarf mutant lkb of garden pea (Pisum sativum L.). In this assay, 26-norbrassinolide was as effective as brassinolide and 26-norcastasterone was more effective than castasterone although 26-nor-6-deoxocastasterone was much less effective than 6-deoxocastasterone. Therefore, removal of C-26 of brassinosteroids does not necessarily reduce the biological activity. The role of C-26 removal in Marchantia cells remains unclear.

  20. The influence of magnesium supplementation on concentrations of chosen bioelements and toxic metals in adult human hair. Magnesium and chosen bioelements in hair.

    PubMed

    Kozielec, Tadeusz; Sałacka, Anna; Karakiewicz, Beata

    2004-09-01

    The basic functions of bioelements in biological systems is widely known. Depletion of bioelements and excess of toxic elements lead to impairment of metabolism in the living organism. The existence of magnesium deficiencies in the adult and pediatric populations may cause increased accumulation of toxic metals including lead and cadmium. Prevention of adverse effects of toxic metals may include supplementation with some bioelements and vitamins. The aim of this study was to evaluate the influence of magnesium supplementation on concentrations of chosen bioelements and toxic metals in hair in the adult human population. The research was performed on 124 individuals (53 males and 71 females aged 19-72 years), inhabitants of the city of Szczecin. The concentrations of magnesium, zinc, copper, lead and cadmium were studied in hair. Measurements were performed using the inversion volt-amperometry method with application of an EDD-Tribo PC ETP volt-amperometer. Finally, the supplementation study enrolled 65 individuals with an increased concentration of lead. The studied individuals were divided into two groups: one treated group that enrolled 50 patients who were supplemented with magnesium and the control group that enrolled 15 persons receiving placebo. Finally, supplementation was completed by 32 individuals from the treated group and 10 individuals from the control group. Supplementation was performed using Slow-Mag-B6 preparation at the total daily dose of five tablets divided into 2-3 doses. One tablet contains 535 mg of magnesium chloride i.e. 64 mg of magnesium ions (5.26 mEgMg2) and 5 mg of vitamin B6. Supplementation was performed for a period of 3 months. The remaining individuals did not complete the supplementation due to various reasons; however, none of them resulted from the poor tolerance of the preparation or its adverse events. The results achieved underwent statistical analysis. The results of the study revealed a positive influence of

  1. Magnesium: Is It a Viable Option?

    DTIC Science & Technology

    2012-08-01

    strike - High alkalinity • Magnesium strike – High alkalinity • Electroless Nickel - formulated to prevent attach of magnesium. Success Stories...ionic palladium, palladium reducer, electroless copper and electroless nickel. The initial results were encouraging: We were able to Get the parts

  2. An automated method for serum magnesium estimation

    PubMed Central

    Whitmore, D. N.; Evans, D. I. K.

    1964-01-01

    An automated method for magnesium determination in serum is described using conventional AutoAnalyser equipment. The method gives results comparable with those obtained by the flame photometer. The method may prove particularly useful with subnormal serum magnesium levels. PMID:14227433

  3. Nanostructured magnesium increases bone cell density

    NASA Astrophysics Data System (ADS)

    Weng, Lucy; Webster, Thomas J.

    2012-12-01

    Magnesium has attracted some attention in orthopedics due to its biodegradability and mechanical properties. Since magnesium is an essential natural mineral for bone growth, it can be expected that as a biomaterial, it would support bone formation. However, upon degradation in the body, magnesium releases OH- which results in an alkaline pH that can be detrimental to cell density (for example, osteoblasts or bone forming cells). For this reason, modification of magnesium may be necessary to compensate for such detrimental effects to cells. This study created biologically inspired nanoscale surface features on magnesium by soaking magnesium in various concentrations of NaOH (from 1 to 10 N) and for various periods of time (from 10 to 30 min). The results provided the first evidence of increased roughness, surface energy, and consequently greater osteoblast adhesion, after 4 h as well as density up to 7 days on magnesium treated with any concentration of NaOH for any length of time compared to untreated controls. For these reasons, this study suggests that soaking magnesium in NaOH could be an inexpensive, simple and effective manner to promote osteoblast functions for numerous orthopedic applications and, thus, should be further studied.

  4. Structurally characterized 1,1,3,3-tetramethylguanidine solvated magnesium aryloxide complexes: [Mg(mu-OEt)(DBP)(H-TMG)]2, [Mg(mu-OBc)(DBP)(H-TMG)]2, [Mg(mu-TMBA)(DBP)(H-TMG)]2, [Mg(mu-DPP)(DBP)(H-TMG)]2, [Mg(BMP)2(H-TMG)2], [Mg(O-2,6-Ph2C6H3)2 (H-TMG)2].

    PubMed

    Monegan, Jessie D; Bunge, Scott D

    2009-04-06

    The synthesis and structural characterization of several 1,1,3,3-tetramethylguanidine (H-TMG) solvated magnesium aryloxide complexes are reported. Bu(2)Mg was successfully reacted with H-TMG, HOC(6)H(3)(CMe(3))(2)-2,6 (H-DBP), and either ethanol, a carboxylic acid, or diphenyl phosphate in a 1:1 ratio to yield the corresponding [Mg(mu-L)(DBP)(H-TMG)](2) where L = OCH(2)CH(3) (OEt, 1), O(2)CC(CH(3))(3) (OBc, 2), O(2)C(C(6)H(2)-2,4,6-(CH(3))(3)) (TMBA, 3), or O(2)P(OC(6)H(5))(2) (DPP, 4). Bu(2)Mg was also reacted with two equivalents of H-TMG and HOC(6)H(3)(CMe(3))-2-(CH(3))-6 (BMP) or HO-2,6-Ph(2)C(6)H(3) to yield [Mg(BMP)(2)(H-TMG)(2)] (5) and [Mg(O-2,6-Ph(2)C(6)H(3))(2)(H-TMG)(2)] (6). Compounds 1-6 were characterized by single-crystal X-ray diffraction. Polymerization of l- and rac-lactide with 1 was found to generate polylactide (PLA). A discussion concerning the relevance of compounds 2 - 4 to the structure of Mg-activated phosphatase enzymes is also provided. The bulk powders for all complexes were found to be in agreement with the crystal structures based on elemental analyses, FT-IR spectroscopy, and (1)H, (13)C and (31)P NMR studies.

  5. Ionized and total magnesium concentration in patients with severe preeclampsia-eclampsia undergoing magnesium sulfate therapy.

    PubMed

    Aali, Bibi Shahnaz; Khazaeli, Payam; Ghasemi, Fatemeh

    2007-04-01

    As ionized magnesium is the active form of magnesium and exerts a therapeutic effect, the present study was performed to determine the levels and correlations between ionized and total magnesium under baseline and therapeutic conditions in patients with severe preeclampsia and eclampsia receiving magnesium sulfate. Fifty singleton patients with severe preeclampsia received a loading dose of 4 g of magnesium sulfate, followed by 2 g per hour as maintenance dose until 24 h after delivery, or 24 h after the last seizure in case of postpartum convulsions. Serial blood samples were taken before magnesium sulfate infusion, 30 min and 240 min after the initiation of the infusion and 4 h after the discontinuation of the drug. Data were analyzed by repeated measure ANOVA and paired t-test. Baseline levels of total and ionized magnesium were 2.4+/-0.6 mEq/L and 1.3+/-0.5 mEq/L (mean+/-SD), respectively. Putative level of 4 mEq/L of total magnesium was not obtained in up to 42% of patients during the treatment. There was not any significant correlation between the two forms of magnesium under baseline and therapeutic conditions. Despite the effectiveness of the standard regimen of magnesium sulfate in the treatment and prevention of eclamptic seizures, it can not provide the proposed therapeutic level of magnesium in all patients. With respect to the lack of correlation between ionized and total magnesium, further studies are necessary to investigate the superiority of measurement of ionized, rather than total magnesium, for titration of therapeutic magnesium sulfate infusion.

  6. Towards a better understanding of magnesium-isotope ratios from marine skeletal carbonates

    NASA Astrophysics Data System (ADS)

    Hippler, Dorothee; Buhl, Dieter; Witbaard, Rob; Richter, Detlev K.; Immenhauser, Adrian

    2009-10-01

    This study presents magnesium stable-isotope compositions of various biogenic carbonates of several marine calcifying organisms and an algae species, seawater samples collected from the western Dutch Wadden Sea, and reference materials. The aim of this study is to explore the influence of mineralogy, taxonomy and environmental factors (e.g., seawater isotopic composition, temperature, salinity) on magnesium-isotopic (δ 26Mg) ratios of skeletal carbonates. Using high-precision multi-collector inductively coupled plasma mass spectrometry, we observed that the magnesium-isotopic composition of seawater from the semi-enclosed Dutch Wadden Sea is identical to that of open marine seawater. We further found that a considerable component of the observed variability in δ 26Mg values of marine skeletal carbonates can be attributed to differences in mineralogy. Furthermore, magnesium-isotope fractionation is species-dependent, with all skeletal carbonates being isotopically lighter than seawater. While δ 26Mg values of skeletal aragonite and high-magnesium calcite of coralline red algae indicate the absence or negligibility of metabolic influences, the δ 26Mg values of echinoids, brachiopods and bivalves likely result from a taxon-specific level of control on Mg-isotope incorporation during biocalcification. Moreover, no resolvable salinity and temperature effect were observed for coralline red algae and echinoids. In contrast, Mg-isotope data of bivalves yield ambiguous results, which require further validation. The data presented here, point to a limited use of Mg isotopes as temperature proxy, but highlight the method's potential as tracer of seawater chemistry through Earth's history.

  7. Determination of phosphorus fertilizer soil reactions by Raman and synchrotron infrared microspectroscopy.

    PubMed

    Vogel, Christian; Adam, Christian; Sekine, Ryo; Schiller, Tara; Lipiec, Ewelina; McNaughton, Don

    2013-10-01

    The reaction mechanisms of phosphate-bearing mineral phases from sewage sludge ash-based fertilizers in soil were determined by Raman and synchrotron infrared microspectroscopy. Different reaction mechanisms in wet soil were found for calcium and magnesium (pyro-) phosphates. Calcium orthophosphates were converted over time to hydroxyapatite. Conversely, different magnesium phosphates were transformed to trimagnesium phosphate. Since the magnesium phosphates are unable to form an apatite structure, the plant-available phosphorus remains in the soil, leading to better growth results observed in agricultural pot experiments. The pyrophosphates also reacted very differently. Calcium pyrophosphate is unreactive in soil. In contrast, magnesium pyrophosphate quickly formed plant-available dimagnesium phosphate.

  8. Magnesium in obstetric anesthesia and intensive care.

    PubMed

    Kutlesic, Marija S; Kutlesic, Ranko M; Mostic-Ilic, Tatjana

    2017-02-01

    Magnesium, one of the essential elements in the human body, has numerous favorable effects that offer a variety of possibilities for its use in obstetric anesthesia and intensive care. Administered as a single intravenous bolus dose or a bolus followed by continuous infusion during surgery, magnesium attenuates stress response to endotracheal intubation, and reduces intraoperative anesthetic and postoperative analgesic requirements, while at the same time preserving favorable hemodynamics. Applied as part of an intrathecal or epidural anesthetic mixture, magnesium prolongs the duration of anesthesia and diminishes total postoperative analgesic consumption with no adverse maternal or neonatal effects. In obstetric intensive care, magnesium represents a first-choice medication in the treatment and prevention of eclamptic seizures. If used in recommended doses with close monitoring, magnesium is a safe and effective medication.

  9. Lloyd M. Pidgeon — Magnesium Pioneer

    NASA Astrophysics Data System (ADS)

    Brown, Robert E.

    Lloyd Montgomery Pidgeon was an unusual man in an unusual time. His contributions to the development of the magnesium industry have never been appreciated (or even known) by many of today's magnesium followers. Dr. Pidgeon, working with one technical graduate, achieved commercial development of a process to produce magnesium by reducing calcined dolomite with ferrosilicon, i.e. the silicothermic process. He also received patents for electrolytic magnesium processes. He worked with engineers to design and build six magnesium production plants in a very short period of time. The original plant at Haley, Ontario is still operating. Dr. Pidgeon received many technical honors, but was always quick-witted, with a humorous approach to life.

  10. Comparison of nanostructured nickel zinc ferrite and magnesium copper zinc ferrite prepared by water-in-oil microemulsion

    NASA Astrophysics Data System (ADS)

    Hee, Ay Ching; Mehrali, Mehdi; Metselaar, Hendrik Simon Cornelis; Mehrali, Mohammad; Osman, Noor Azuan Abu

    2012-12-01

    Ferrite is an important ceramic material with magnetic properties that are useful in many types of electronic devices. In this study, structure and magnetic properties of nanostructured nickel zinc ferrite and magnesium copper zinc ferrite prepared by water-in-oil microemulsion were compared. Both ferrites samples demonstrated similar weight loss characteristics in TGA. The magnesium copper zinc ferrite showed a crystalline structure with an average crystallite size of 13.5 nm. However, nickel zinc ferrite showed an amorphous phase. Transmission electron micrographs showed agglomerated nanoparticles with an average crystallite size of 26.6 nm for magnesium copper zinc ferrite and 22.7 nm for nickel zinc ferrite. Magnesium copper zinc ferrite exhibited soft ferromagnetic bahaviour whereas nickel zinc ferrite showed superparamagnetic nature.

  11. Experimental determination of magnesium isotope fractionation during higher plant growth

    NASA Astrophysics Data System (ADS)

    Bolou-Bi, Emile B.; Poszwa, Anne; Leyval, Corinne; Vigier, Nathalie

    2010-05-01

    Two higher plant species (rye grass and clover) were cultivated under laboratory conditions on two substrates (solution, phlogopite) in order to constrain the corresponding Mg isotope fractionations during plant growth and Mg uptake. We show that bulk plants are systematically enriched in heavy isotopes relative to their nutrient source. The Δ 26Mg plant-source range from 0.72‰ to 0.26‰ for rye grass and from 1.05‰ to 0.41‰ for clover. Plants grown on phlogopite display Mg isotope signatures (relative to the Mg source) ˜0.3‰ lower than hydroponic plants. For a given substrate, rye grass display lower δ 26Mg (by ˜0.3‰) relative to clover. Magnesium desorbed from rye grass roots display a δ 26Mg greater than the nutrient solution. Adsorption experiments on dead and living rye grass roots also indicate a significant enrichment in heavy isotopes of the Mg adsorbed on the root surface. Our results indicate that the key processes responsible for heavy isotope enrichment in plants are located at the root level. Both species also exhibit an enrichment in light isotopes from roots to shoots (Δ 26Mg leaf-root = -0.65‰ and -0.34‰ for rye grass and clover grown on phlogopite respectively, and Δ 26Mg leaf-root of -0.06‰ and -0.22‰ for the same species grown hydroponically). This heavy isotope depletion in leaves can be explained by biological processes that affect leaves and roots differently: (1) organo-Mg complex (including chlorophyll) formation, and (2) Mg transport within plant. For both species, a positive correlation between δ 26Mg and K/Mg was observed among the various organs. This correlation is consistent with the link between K and Mg internal cycles, as well as with formation of organo-magnesium compounds associated with enrichment in heavy isotopes. Considering our results together with the published range for δ 26Mg of natural plants and rivers, we estimate that a significant change in continental vegetation would induce a change of

  12. Comparison of magnesium status using X-ray dispersion analysis following magnesium oxide and magnesium citrate treatment of healthy subjects.

    PubMed

    Shechter, Michael; Saad, Tomer; Shechter, Alon; Koren-Morag, Nira; Silver, Burton B; Matetzky, Shlomi

    2012-03-01

    The magnesium content in food consumed in the Western world is steadily decreasing. Hypomagnesemia is associated with increased incidence of diabetes mellitus, metabolic syndrome, all-cause and coronary artery disease mortality. We investigated the impact of supplemental oral magnesium citrate versus magnesium oxide on intracellular magnesium levels ([Mg2+]i) and platelet function in healthy subjects with no apparent heart disease. In a randomized, prospective, double-blind, crossover study, 41 (20 women) healthy volunteers [mean age 53±8 (range 31-75) years] received either magnesium oxide monohydrate tablets (520 mg/day of elemental magnesium) or magnesium citrate tablets (295.8 mg/day of elemental magnesium) for one month (phase 1), followed by a four-week wash-out period, and then crossover treatment for one month (phase 2). [Mg2+]i was assessed from sublingual cells through x-ray dispersion (normal values 37.9±4.0 mEq/L), serum magnesium levels, platelet aggregation, and quality-of-life questionnaires were assessed before and after each phase. Oral magnesium oxide, rather than magnesium citrate, significantly increased [Mg2+]i (34.4±3 versus 36.3±2 mEq/L, p<0.001 and 34.7±2 versus 35.4±2 mEq/L, p=0.097; respectively), reduced total cholesterol (201±37 versus 186±27 mg/dL, p=0.016 and 187±28 versus 187±25 mg/dL, p=0.978; respectively) and low-density lipoprotein (LDL) cholesterol (128±22 versus 120±25 mg/dL, p=0.042 and 120±23 versus 121±22 mg/dL, p=0.622; respectively). Noteworthy is that both treatments significantly reduced epinephrine-induced platelet aggregation (78.9±16% versus 71.7±23%, p=0.013 and 81.3±15% versus 73.3±23%, p=0.036; respectively). Thus, oral magnesium oxide treatment significantly improved [Mg2+]i, total and LDL cholesterol compared with magnesium citrate, while both treatments similarly inhibited platelet aggregation in healthy subjects with no apparent heart disease.

  13. Complex of hexamethylenetetramine with magnesium-tetraphenylporphyrin: Synthesis, structure, spectroscopic characterizations and electrochemical properties

    NASA Astrophysics Data System (ADS)

    Ezzayani, Khaireddine; Ben Khelifa, Arbia; Saint-Aman, Eric; Loiseau, Frederique; Nasri, Habib

    2017-06-01

    A new crystalline material of a magnesium (II)-porphyrin complex was prepared and characterized by single crystal X-ray diffraction. The molecular structure is made by (5,10,15,20-tetraphenylporphyrinato-κ4N)bis(hexamethylenetetramine) magnesium dichloromethane disolvate. The title compound crystallizes in the orthorhombic system, space group Pbcn, with a = 19.2932 (6) Å, b = 10.4878 (4) Å, c = 26.0025 (14) Å, V = 5261.4 (4) Å3 and Z = 4. The supramolecular architecture includes weak C__H⋯N hydrogen bond. This magnesium-porphyrin species was also characterized by UV-visible, IR and fluorescence spectroscopy and a cyclic voltammetry investigation was also carried out on this species.

  14. Interactions between magnesium and psychotropic drugs.

    PubMed

    Nechifor, Mihai

    2008-06-01

    Psychotropic drugs (antidepressants, antimanic drugs, antipsychotics, analgesic opioids, and others) are among the most frequently used medicines. Between these drugs and magnesium there are pharmacokinetic and pharmacodynamic interactions. Erythrocyte magnesium is decreased in patients with severe major depression (MD) vs normal subjects (44 +/- 2.7 mg/L in MD group vs 59.1 +/- 3.2 mg/L in control group, p < 0.01). Therapy with sertraline, 150 mg/day p.o. -21 days or with amitryptiline 3 x 25 mg/day p.o. 28 days increases significantly erythrocyte concentration of magnesium (56.9 +/- 5.22 mg/L after sertraline vs 44 +/- 2.7 mg/L before sertraline, p < 0.01). In patients with acute paranoid schizophrenia, erythrocyte magnesium concentration is decreased vs healthy subjects. Haloperidol, 8 mg/day, p.o. for 21 days or risperidone, 6 mg/day p.o. for 21 days have increased significantly erythrocyte magnesium concentration (46.21 +/- 3.1 mg/L before haloperidol and 54.6 +/- 2.7 mg/L after haloperidol, p < 0.05). Antimanic drugs (mood stabilizers) as carbamazepine, 600 mg/day, p.o., 4 weeks and sodium valproate, 900 mg/day p.o., 4 weeks, increased significantly magnesium in patients with bipolar disorder type I. Increased magnesium status positively correlated with enhancement of the clinical state. The existent data sustain the idea that an increase of erythrocyte magnesium is involved in the mechanism of action of some psychotropic drugs. Magnesium supply decreased the intensity of morphine-induced physical drug dependence. In heroin addicts, the plasma magnesium concentration is decreased.

  15. Status of Research on Magnesium Oxide Backfill

    SciTech Connect

    PAPENGUTH,HANS W.; KRUMHANSL,JAMES L.; BYNUM,R. VANN; WANG,YIFENG; KELLY,JOHN W.; ANDERSON,HOWARD; NOWAK,E. JAMES

    2000-07-31

    For the WIPP, chemical and physical characteristics of MgO suggest it to be the most beneficial backfill choice, particularly because it has the ability to buffer the aqueous chemical conditions to control actinide volubility. In the current experimental program, the authors are developing a technical basis for taking credit for the complete set of attributes of MgO in geochemical, hydrogeological, and geomechanical technical areas, resulting in an improved conceptual model for the WIPP such as the following. Water uptake by MgO will delay the development of mobile actinides and gas generation by microbes and corrosion. Reduced gas generation will reduce or even eliminate spallings releases. As MgO hydrates, it swells, reducing porosity and permeability, which will inhibit gas flow in the repository, in turn reducing spallings releases. Hydration will also result in a self-sealing mechanism by which water uptake and swelling of MgO adjacent to a groundwater seep cuts off further seepage. Reaction with some groundwaters will produce cementitious materials, which will help to cement waste particles or produce a cohesive solid mass. Larger particles are less likely to be entrained in a spallings release. If sufficient water eventually accumulates in a repository to support microbial gas generation, magnesium carbonate cements will form; also producing good cohesion and strength.

  16. The magnesium chelation step in chlorophyll biosynthesis

    SciTech Connect

    Weinstein, J.D.

    1991-01-01

    The biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins and lipids. Two of the major prosthetic groups, chlorophyll and heme, share a common biosynthetic pathway that diverges at the point of metal insertion into protoporphyrin IX. Insertion of iron leads to heme, while insertion of magnesium leads to chlorophyll. The Mg-chelatase from intact cucumber chloroplasts has been characterized with regard to substrate specificity, regulation, ATP requirement, and a requirement for intact chloroplasts. Mg-chelatase was isolated from maize, barley and peas and characterized in order to circumvent the intact chloroplast requirement of cucumber Mg-chelatase. Pea Mg-chelatase activity is higher than cucumber Mg-chelatase activity, and lacks the requirement for intact chloroplasts. Studies on isolated pea Mg-chelatase have shown more cofactors are required for the reaction than are seen with ferrochelatase, indicating a greater opportunity for regulatory control of this pathway. Two of the cofactors are proteins, and there appears to be a requirement for a protease-sensitive component which is outside the outer envelope. We are developing a continuous spectrophotometric assay for Mg-chelatase activity, and an assay for free heme which has shown heme efflux from intact chloroplasts. 18 refs. (MHB)

  17. The Phase Stabilities of Magnesium Hydroxychlorides

    NASA Astrophysics Data System (ADS)

    de Bakker, Jan; LaMarre, Joshua; Peacey, John; Davis, Boyd

    2012-08-01

    This work presents experimental determinations of oxide phase stabilities in the MgCl2-MgO-H2O system. Magnesium hydroxychlorides are compounds with the overall stoichiometry xMgO· yMgCl2· zH2O, which form from the reaction of MgO with MgCl2 brines. They have historically been of importance as the components of Sorel cements; they also have a central role in proposed flowsheets for chloride leaching of laterite nickel ores (among others) and treatment of waste liquors from carnallite processing. A phase diagram of the MgCl2-MgO-H2O system is presented, incorporating both this investigation's results and the values from the literature. Thermochemical values of the 2-form and 3-form hydroxychlorides are estimated from the phase diagram. In addition, a scanning electron microscopy (SEM) micrograph of the hydroxychloride precipitate is presented. The highlights of this article are as follows: Precipitates of stoichiometry xMgO· yMgCl2· zH2O were obtained by adding MgO to MgCl2 solutions.

  18. High-Dose Magnesium Sulfate Infusion for Severe Asthma in the Emergency Department: Efficacy Study.

    PubMed

    Irazuzta, Jose E; Paredes, Fatima; Pavlicich, Viviana; Domínguez, Sara L

    2016-02-01

    To assess the efficacy of a high-dose prolonged magnesium sulfate infusion in patients with severe, noninfectious-mediated asthma. Prospective, randomized, open-label study. Twenty-nine-bed pediatric emergency department located in a children's hospital in Asuncion, Paraguay. All patients of 6-16 years old who failed to improve after 2 hours of standard therapy for asthma. Subjects were randomized to receive magnesium sulfate, 50 mg/kg over 1 hour (bolus) or high-dose prolonged magnesium sulfate infusion of 50 mg/kg/hr for 4 hours (max, 8.000 mg/4 hr). Patients were monitored for cardiorespiratory complications. Asthma severity was assessed via asthma scores and peak expiratory flow rates at 0-2-6 hours. The primary outcome was discharge to home at 24 hours. An analysis of the hospital length of stay and costs was a secondary outcome. Thirty-eight patients were enrolled, 19 in each group. The groups were of similar ages, past medical history of asthma, asthma score, and peak expiratory flow rate. There was a significant difference in the patients discharged at 24 hours: 47% in high-dose prolonged magnesium sulfate infusion (9/19) versus 10% (2/21) in the bolus group (p = 0.032) with an absolute risk reduction 37% (95% CI, 10-63) and a number needed to treat of 2.7 (95% CI, 1.6-9.5) to facilitate a discharge at or before 24 hours. The length of stay was shorter in the high-dose prolonged magnesium sulfate infusion group (mean ± SD in hr: high-dose prolonged magnesium sulfate infusion, 34.13 ± 19.54; bolus, 48.05 ± 18.72; p = 0.013; 95% CI, 1.3-26.5). The cost per patient in the high-dose prolonged magnesium sulfate infusion group was one third lower than the bolus group (mean ± SD: high-dose prolonged magnesium sulfate infusion, $603.16 ± 338.47; bolus, $834.37 ± 306.73; p < 0.016). There were no interventions or discontinuations of magnesium sulfate due to adverse events. The early utilization of high-dose prolonged magnesium sulfate infusion (50 mg/kg/hr/4

  19. Tape casting of magnesium oxide.

    SciTech Connect

    Ayala, Alicia; Corral, Erica L.; Loehman, Ronald E.; Bencoe, Denise Nora; Reiterer, Markus; Shah, Raja A.

    2008-02-01

    A tape casting procedure for fabricating ceramic magnesium oxide tapes has been developed as a method to produce flat sheets of sintered MgO that are thin and porous. Thickness of single layer tapes is in the range of 200-400 {micro}m with corresponding surface roughness values in the range of 10-20 {micro}m as measured by laser profilometry. Development of the tape casting technique required optimization of pretreatment for the starting magnesium oxide (MgO) powder as well as a detailed study of the casting slurry preparation and subsequent heat treatments for sintering and final tape flattening. Milling time of the ceramic powder, plasticizer, and binder mixture was identified as a primary factor affecting surface morphology of the tapes. In general, longer milling times resulted in green tapes with a noticeably smoother surface. This work demonstrates that meticulous control of the entire tape casting operation is necessary to obtain high-quality MgO tapes.

  20. Identifying acid salts of magnesium

    SciTech Connect

    Plumb, R.; Thivierge, R.F. Jr.; Xu, W.W.

    1987-11-05

    In preliminary work they found that significant quantities of certain nitrogen oxides and of sulfuric acid were absorbed by lower hydrates of magnesium sulfate. It appeared that acid salts were being formed but the known chemistry of group IIA (group 2) sulfates and acid sulfates which was worked out many years ago did not provide an explanation of their observations. They developed a new technique for delineating the solidus boundary of ternary mixtures using friability tests and applied it to the systems of interest. Magnesium acid salt hydrates with compositions on the solidus boundary could be readily identified. X-ray powder patterns confirmed the existence of two previously unknown ternary compounds, Mg/sub 2/(HSO/sub 4/)/sub 2/SO/sub 4/ x 4H/sub 2/O and Mg(HSO/sub 4/)/sub 2/ x H/sub 2/SO/sub 4/ x 3H/sub 2/O. Mixed acid sulfate-nitrate-hydrates could be detected but fuming at room temperatures interfered with quantitative determinations of the solidus boundary and X-ray measurements.

  1. Analysis Methods of Magnesium Chips

    NASA Astrophysics Data System (ADS)

    Ohmann, Sven; Ditze, André; Scharf, Christiane

    2015-11-01

    The quality of recycled magnesium from chips depends strongly on their exposure to inorganic and organic impurities that are added during the production processes. Different kinds of magnesium chips from these processes were analyzed by several methods. In addition, the accuracy and effectiveness of the methods are discussed. The results show that the chips belong either to the AZ91, AZ31, AM50/60, or AJ62 alloy. Some kinds of chips show deviations from the above-mentioned normations. Different impurities result mainly from transition metals and lime. The water and oil content does not exceed 25%, and the chip size is not more than 4 mm in the diameter. The sieve analysis shows good results for oily and wet chips. The determination of oil and water shows better results for the application of a Soxhlet compared with the addition of lime and vacuum distillation. The most accurate values for the determination of water and oil are obtained by drying at 110°C (for water) and washing with acetone (for oil) by hand.

  2. Intracellular and extracellular blood magnesium fractions in hemodialysis patients; is the ionized fraction a measure of magnesium excess?

    PubMed

    Huijgen, H J; Sanders, R; van Olden, R W; Klous, M G; Gaffar, F R; Sanders, G T

    1998-03-01

    To establish the best measure for determining magnesium overload, we measured ionized and total magnesium in serum and mononuclear blood cells and total magnesium in erythrocytes in blood of 23 hemodialysis patients, known for their disturbed magnesium homeostasis. When comparing the mean magnesium values obtained in the patient population with those of a control population, all of these magnesium markers, including the biologically active fractions, were significantly (P < 0.05) increased. Because serum total magnesium was not increased in all dialysis patients studied, the population was divided into two groups, according to total serum magnesium > 1.0 mmol/L or less than that. Results in these two populations showed that ionized serum magnesium and ionized magnesium in mononuclear blood cells might give a better indication about the magnesium status of the tested patients than the currently used total serum magnesium data. However, neither of the two markers, especially ionized serum magnesium, was able to discriminate fully between normal magnesium homeostasis and magnesium excess. We therefore conclude that the two ionized magnesium markers offer minimal advantage for this discrimination, and that the total magnesium concentration in serum remains the measurement of choice.

  3. Paramagnetic complexes of magnesium as mediators in enzymatic ATP synthesis: DFT calculations of magnetic parameters

    NASA Astrophysics Data System (ADS)

    Buchachenko, A. L.; Shchegoleva, L. N.; Breslavskaya, N. N.

    2009-11-01

    Magnetic parameters ( g-factors, hyperfine coupling constants a( 25Mg) and a( 31P)) of paramagnetic pyrophosphate and hydrate magnesium complexes, which model those in catalytic site of the ATP synthesizing enzymes, are calculated. Both g-factors and HFС constants a( 31P) of the paramagnetic pyrophosphate magnesium complexes are identical to those of the pyrophosphate radical. It demonstrates that namely terminal PO 3 group of the liganded ADP in the complex Mg 2+(ADP) 3- donates electron to the Mg(HO)n2+ ion in the primary reaction of the ion-radical mechanism of enzymatic ATP synthesis.

  4. LACK OF ASSOCIATION BETWEEN SERUM MAGNESIUM AND THE RISKS OF HYPERTENSION AND CARDIOVASCULAR DISEASE

    PubMed Central

    Khan, Abigail May; Sullivan, Lisa; McCabe, Elizabeth; Levy, Daniel; Vasan, Ramachandran S.; Wang, Thomas J.

    2010-01-01

    Background Experimental studies have linked hypomagnesemia with the development of vascular dysfunction, hypertension, and atherosclerosis. Prior clinical studies have yielded conflicting results, but were limited by the use of self-reported magnesium intake or short follow-up periods. Methods We examined the relationship between serum magnesium concentration and incident hypertension, cardiovascular disease, and mortality in 3,531 middle-aged adult participants in the Framingham Heart Study offspring cohort. Analyses were performed using Cox proportional hazards regressions, adjusted for traditional cardiovascular disease risk factors. Results Follow up was 8 years for new-onset hypertension (551 events) and 20 years for cardiovascular disease (554 events). There was no association between baseline serum magnesium and the development of hypertension (multivariable-adjusted hazards ratio per 0.15 mg/dl, 1.03, 95% confidence interval [CI], 0.92-1.15; p=0.61), cardiovascular disease (0.77, 95% CI, 0.44-1.37; p=0.49) or all-cause mortality (0.64, 95% CI, 0.32-1.26; p=0.42). Similar findings were observed in categorical analyses, in which serum magnesium was modeled in categories (<1.5, 1.5-2.2, >2.2 mg/dl) or in quartiles. Conclusions In conclusion, data from this large, community-based cohort do not support the hypothesis that low serum magnesium is a risk factor for developing hypertension or cardiovascular disease. PMID:20934566

  5. Magnesium status and the effect of magnesium supplementation in feline hypertrophic cardiomyopathy.

    PubMed Central

    Freeman, L M; Brown, D J; Smith, F W; Rush, J E

    1997-01-01

    Magnesium deficiency has been associated with the development of cardiovascular disease in several species. Cats may be predisposed to alterations in magnesium status because of recent changes in the composition of commercial feline diets. The purposes of this study were 1) to examine the dietary history of cats with hypertrophic cardiomyopathy (HCM), 2) to study magnesium status of cats with HCM compared to normal cats, and 3) to determine the effects of magnesium supplementation in cats with HCM. In part 1 of the study, diets of 65 cats with HCM were examined retrospectively. Forty of the 45 cats for which diets could be determined (89%) ate a diet designed to be magnesium-restricted and/or to produce an acidic urine. In part 2 of the study, 10 cats with HCM were compared to 10 healthy control cats for serum creatinine and magnesium; urine creatinine and magnesium, urine specific gravity and pH, and fractional excretion of magnesium. Urine creatinine and specific gravity were higher in control cats than in cats with HCM. No other differences were found between the 2 groups. In part 3, cats with HCM were supplemented with either 210 mg magnesium chloride (n = 15) or 210 mg lactose (n = 15) for 12 wk. No differences between the 2 groups were found for changes in either magnesium status or echocardiographic parameters. However, the 30 cats with HCM, as a group, did show significant improvements in measures of cardiac hypertrophy over the 12-week period. This was likely the result of treatment with other medications, rather than the magnesium supplementation. The results of this study suggest that cats with HCM are likely to be fed magnesium-restricted diets, but that they do not appear to have altered magnesium status compared to healthy controls. PMID:9243004

  6. Optimized carbonation of magnesium silicate mineral for CO2 storage.

    PubMed

    Eikeland, Espen; Blichfeld, Anders Bank; Tyrsted, Christoffer; Jensen, Anca; Iversen, Bo Brummerstedt

    2015-03-11

    The global ambition of reducing the carbon dioxide emission makes sequestration reactions attractive as an option of storing CO2. One promising environmentally benign technology is based on forming thermodynamically stable carbonated minerals, with the drawback that these reactions usually have low conversion rates. In this work, the carbonation reaction of Mg rich olivine, Mg2SiO4, under supercritical conditions has been studied. The reaction produces MgCO3 at elevated temperature and pressure, with the addition of NaHCO3 and NaCl to improve the reaction rates. A sequestration rate of 70% was achieved within 2 h, using olivine particles of sub-10 μm, whereas 100% conversion was achieved in 4 h. This is one of the fastest complete conversions for this reaction reported to date. The CO2 sequestration rate is found to be highly dependent on the applied temperature and pressure, as well as the addition of NaHCO3. In contrast, adding NaCl was found to have limited effect on the reaction rate. The roles of NaHCO3 and NaCl as catalysts are discussed and especially how their effect changes with increased olivine particle size. The products have been characterized by Rietveld refinement of powder X-ray diffraction, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy revealing the formation of amorphous silica and micrometer-sized magnesium carbonate crystals.

  7. [Diagnosis of magnesium deficiency in intensive care patients].

    PubMed

    Saur, P M; Zielmann, S; Roth, A T; Frank, L; Warneke, G; Radke, A; Ensink, F B; Kettler, D

    1996-02-01

    Magnesium deficiency was investigated in critically ill patients, comparing measurements of plasma concentrations with the results obtained by the magnesium tolerance test. 20 critically ill patients (5 females, 15 males) between the ages of 27 and 86 were investigated. Magnesium plasma concentrations were determined before the magnesium tolerance test according to Ryzen was performed. For this purpose, magnesium sulfate (0.1 mmol/kg) was infused intravenously over four hours. Renal magnesium excretion was measured in the 24 h urine beginning at the start of the infusion. Magnesium concentrations in plasma and urine were determined using atomic absorption spectrophotometry. In 12 patients magnesium plasma concentrations were decreased to 0.58-0.79 mmol/l. 6 patients showed values within the normal range of 0.80 to 1.0 mmol/l. In 2 patients the plasma concentration was increased to 1.07 and 1.27 mmol/l. Parenteral magnesium tolerance testing revealed a considerable magnesium deficiency by retention of 65-100% of the loading dose in 14 of the 20 patients. The remaining 6 patients retained 23-48% of the loading dose, thus demonstrating a moderate magnesium deficiency. Determination of magnesium plasma concentration appears suitable as an informative preliminary survey, since low values are reliable indicating a magnesium deficiency. However, this study confirms that normal magnesium plasma concentrations do not exclude a considerable magnesium deficiency, which is more sensitively determined by the magnesium tolerance test.

  8. The unexpected discovery of the Mg(HMDS) 2 /MgCl 2 complex as a magnesium electrolyte for rechargeable magnesium batteries

    DOE PAGES

    Liao, Chen; Sa, Niya; Key, Baris; ...

    2015-02-02

    We developed a unique class of non-Grignard, aluminum-free magnesium electrolytes based on a simple mixture of magnesium compounds: magnesium hexamethyldisilazide (Mg(HMDS)2) and magnesium chloride (MgCl2).

  9. Spectrophotometric study on the proton transfer reaction between 2-amino-4-methylpyridine with 2,6-dichloro-4-nitrophenol in methanol, acetonitrile and the binary mixture 50% methanol+50% acetonitrile.

    PubMed

    Al-Ahmary, Khairia M; Habeeb, Moustafa M; Al-Obidan, Areej H

    2016-02-05

    Proton transfer reaction between 2-amino-4-methylpyridine (2AMP) as the proton acceptor with 2,6-dichloro-4-nitrophenol (DCNP) as the proton donor has been investigated spectrophotometrically in methanol (MeOH), acetonitrile (AN) and a binary mixture composed of 50% MeOH and 50% AN (AN-Me). The composition of the complex has been investigated utilizing Job(')s and photometric titration methods to be 1:1. Minimum-maximum absorbance equation has been applied to estimate the formation constant of the proton transfer reaction (K(PT)) where it reached high values in the investigated solvent confirming its high stability. The formation constant recorded higher value in AN compared with MeOH and mixture of AN-Me. Based on the formation of stable proton transfer complex, a sensitive spectrophotometric method was suggested for quantitative determination of 2AMP. The Lambert-Beer(')s law was obeyed in the concentration range 0.5-8 μg mL(-1) with small values of limits of detection and quantification. The solid complex between 2AMP with DCNP has been synthesized and characterized by elemental analysis to be 1:1 in concordant with the molecular stoichiometry in solution. Further analysis of the solid complex was carried out using infrared and (1)H NMR spectroscopy.

  10. Spectrophotometric study on the proton transfer reaction between 2-amino-4-methylpyridine with 2,6-dichloro-4-nitrophenol in methanol, acetonitrile and the binary mixture 50% methanol + 50% acetonitrile

    NASA Astrophysics Data System (ADS)

    Al-Ahmary, Khairia M.; Habeeb, Moustafa M.; Al-Obidan, Areej H.

    2016-02-01

    Proton transfer reaction between 2-amino-4-methylpyridine (2AMP) as the proton acceptor with 2,6-dichloro-4-nitrophenol (DCNP) as the proton donor has been investigated spectrophotometrically in methanol (MeOH), acetonitrile (AN) and a binary mixture composed of 50% MeOH and 50% AN (AN-Me). The composition of the complex has been investigated utilizing Job's and photometric titration methods to be 1:1. Minimum-maximum absorbance equation has been applied to estimate the formation constant of the proton transfer reaction (KPT) where it reached high values in the investigated solvent confirming its high stability. The formation constant recorded higher value in AN compared with MeOH and mixture of AN-Me. Based on the formation of stable proton transfer complex, a sensitive spectrophotometric method was suggested for quantitative determination of 2AMP. The Lambert-Beer's law was obeyed in the concentration range 0.5-8 μg mL- 1 with small values of limits of detection and quantification. The solid complex between 2AMP with DCNP has been synthesized and characterized by elemental analysis to be 1:1 in concordant with the molecular stoichiometry in solution. Further analysis of the solid complex was carried out using infrared and 1H NMR spectroscopy.

  11. Reductive degradation of oxygenated polycyclic aromatic hydrocarbons using an activated magnesium/co-solvent system.

    PubMed

    Elie, Marc R; Clausen, Christian A; Yestrebsky, Cherie L

    2013-05-01

    This study evaluates the capability of zero-valent magnesium and a protic co-solvent to promote the degradation of oxygenated polycyclic aromatic hydrocarbons compounds, specifically 9-fluorenone, 9,10-anthraquinone, 7,12-benz(a)anthraquionone, and 7H-benz(de)anthracene-7-one. At room temperature conditions, greater than 86% degradation efficiency is observed after 24h of reaction time for a mixture containing 0.05 g of magnesium and four selected oxygenated aromatic hydrocarbons with 250 mg L(-1) concentrations. It is noted that glacial acetic acid is needed as an activator for the degradation reaction to proceed. It is also presumed that the acid removes oxide and hydroxide species from the magnesium surface. With the GC-MS analysis of the reaction products, possible reductive pathways are suggested. Furthermore, this study is the first report on the degradation of these emerging contaminants and it is proposed that the magnesium-powder/protic-solvent system is a promising low-cost reagent and may allow for the future development of an economic and environmentally-friendly remediation application. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Magnesium based degradable biomaterials: A review

    NASA Astrophysics Data System (ADS)

    Gu, Xue-Nan; Li, Shuang-Shuang; Li, Xiao-Ming; Fan, Yu-Bo

    2014-09-01

    Magnesium has been suggested as a revolutionary biodegradable metal for biomedical applications. The corrosion of magnesium, however, is too rapid to match the rates of tissue healing and, additionally, exhibits the localized corrosion mechanism. Thus it is necessary to control the corrosion behaviors of magnesium for their practical use. This paper comprehensively reviews the research progress on the development of representative magnesium based alloys, including Mg-Ca, Mg-Sr, Mg-Zn and Mg-REE alloy systems as well as the bulk metallic glass. The influence of alloying element on their microstructures, mechanical properties and corrosion behaviors is summarized. The mechanical and corrosion properties of wrought magnesium alloys are also discussed in comparison with those of cast alloys. Furthermore, this review also covers research carried out in the field of the degradable coatings on magnesium alloys for biomedical applications. Calcium phosphate and biodegradable polymer coatings are discussed based on different preparation techniques used. We also compare the effect of different coatings on the corrosion behaviors of magnesium alloys substrate.

  13. Magnesium in cardioplegia: Is it necessary?

    PubMed Central

    Shakerinia, Tooraj; Ali, Idris M.; Sullivan, John A.P.

    1996-01-01

    Objective To study the effectiveness of magnesium in cardioplegic solution in preventing postoperative arrhythmias and perioperative ischemia. Design Randomized, control study. Setting The cardiovascular surgery division of a major referral centre for the maritime provinces of Canada. Patients Fifty patients scheduled to undergo coronary artery bypass who had a normal ejection fraction, normal preoperative serum magnesium level and no history of atrial or ventricular arrhythmia were randomized into two groups of 25 patients. One group received magnesium sulfate (15 mmol/L) in the cardioplegic solution (group 1), the other (control) group did not receive magnesium sulfate in the cardioplegic solution (group 2). Intervention Coronary artery bypass grafting during which myocardial protection was provided by intermittent cold blood cardioplegia. Outcome Measures Postoperative serum magnesium levels, cardiac-related death, infarction and arrhythmias. Results All group 2 patients had a lower postoperative serum magnesium level than group 1 patients. There were no cardiac-related deaths in either group. More group 2 patients had ischemic electrocardiographic changes than group 1 patients (p < 0.03). Non-Q-wave myocardial infarction occurred in two patients (one in each group). Eight patients in group 2 had atrial fibrillation compared with five patients in group 1. Ventricular ectopia occurred significantly (p < 0.01) more frequently in group 2 than in group 1. Conclusion The addition of magnesium to the cardioplegic solution is beneficial in reducing the incidence of perioperative ischemia and ventricular arrhythmia in patients who undergo coronary bypass grafting. PMID:8857989

  14. Behavior of bone cells in contact with magnesium implant material.

    PubMed

    Burmester, Anna; Willumeit-Römer, Regine; Feyerabend, Frank

    2017-01-01

    Magnesium-based implants exhibit several advantages, such as biodegradability and possible osteoinductive properties. Whether the degradation may induce cell type-specific changes in metabolism still remains unclear. To examine the osteoinductivity mechanisms, the reaction of bone-derived cells (MG63, U2OS, SaoS2, and primary human osteoblasts (OB)) to magnesium (Mg) was determined. Mg-based extracts were used to mimic more realistic Mg degradation conditions. Moreover, the influence of cells having direct contact with the degrading Mg metal was investigated. In exposure to extracts and in direct contact, the cells decreased pH and osmolality due to metabolic activity. Proliferating cells showed no significant reaction to extracts, whereas differentiating cells were negatively influenced. In contrast to extract exposure, where cell size increased, in direct contact to magnesium, cell size was stable or even decreased. The amount of focal adhesions decreased over time on all materials. Genes involved in bone formation were significantly upregulated, especially for primary human osteoblasts. Some osteoinductive indicators were observed for OB: (i) an increased cell count after extract addition indicated a higher proliferation potential; (ii) increased cell sizes after extract supplementation in combination with augmented adhesion behavior of these cells suggest an early switch to differentiation; and (iii) bone-inducing gene expression patterns were determined for all analyzed conditions. The results from the cell lines were inhomogeneous and showed no specific stimulus of Mg. The comparison of the different cell types showed that primary cells of the investigated tissue should be used as an in vitro model if Mg is analyzed. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 165-179, 2017. © 2015 Wiley Periodicals, Inc.

  15. The magnesium isotope record of cave carbonate archives

    NASA Astrophysics Data System (ADS)

    Riechelmann, S.; Buhl, D.; Schröder-Ritzrau, A.; Riechelmann, D. F. C.; Richter, D. K.; Vonhof, H. B.; Wassenburg, J. A.; Geske, A.; Spötl, C.; Immenhauser, A.

    2012-05-01

    Here we explore the potential of time-series magnesium26Mg) isotope data as continental climate proxies in speleothem calcite archives. For this purpose, a total of six Pleistocene and Holocene stalagmites from caves in Germany, Morocco and Peru and two flowstones from a cave in Austria were investigated. These caves represent the semi-arid to arid (Morocco), the warm-temperate (Germany), the equatorial-humid (Peru) and the cold-humid (Austria) climate zones. Changes in the calcite magnesium isotope signature with time are placed against carbon and oxygen isotope records from these speleothems. Similar to other proxies, the non-trivial interaction of a number of environmental, equilibrium and non-equilibrium processes governs the δ26Mg fractionation in continental settings. These include the different sources of magnesium isotopes such as rain water or snow as well as soil and hostrock, soil zone biogenic activity, shifts in silicate versus carbonate weathering ratios and residence time of water in the soil and karst zone. Pleistocene stalagmites from Morocco show the lowest mean δ26Mg values (GDA: -4.26 ± 0.07 ‰ and HK3: -4.17 ± 0.15 ‰) and the data are well explained in terms of changes in aridity over time. The Pleistocene to Holocene stalagmites from Peru show the highest mean value (NC-A and NC-B δ26Mg: -3.96 ± 0.04 ‰) but only minor variations in Mg-isotope composition, which is in concert with the rather stable equatorial climate at this site. Holocene stalagmites from Germany (AH-1 mean δ26Mg: -4.01 ± 0.07 ‰; BU 4 mean δ26Mg: -4.20 ± 0.10 ‰) record changes in outside air temperature as driving factor rather than rainfall amount. The alpine Pleistocene flowstones from Austria (SPA 52: -3.00 ± 0.73 ‰; SPA 59: -3.70 ± 0.43 ‰) are affected by glacial versus interglacial climate change with outside air temperature affecting soil zone activity and weathering balance. Several data points in the Austrian and two data points in the

  16. Silicone-covered biodegradable magnesium-stent insertion in the esophagus: a comparison with plastic stents.

    PubMed

    Zhu, Yue-Qi; Yang, Kai; Edmonds, Laura; Wei, Li-Ming; Zheng, Reila; Cheng, Ruo-Yu; Cui, Wen-Guo; Cheng, Ying-Sheng

    2017-01-01

    We determined the feasibility of, and tissue response to silicone-covered biodegradable magnesium- and plastic-stent insertion into the esophagus in rabbits. The mechanical compression-recovery characteristics and degradation behaviors of the magnesium stent were investigated in vitro. A total of 45 rabbits were randomly divided into a magnesium- (n = 15) and a plastic- (n = 15) stent group, and underwent stent insertion into the lower third of the esophagus under fluoroscopic guidance; a control group (n = 15) did not undergo the intervention. Esophagography was performed at 1, 2, and 4 weeks. Five rabbits in each group were euthanized at each time point for histological examination. Silicone-covered magnesium stents showed similar radial force to plastic stents (p > 0.05). The magnesium stents degraded rapidly in an acidic solution, but 90.2% ± 3.1% of the residual mass was maintained after a 2-week degradation in a solution with a pH of 4.0. All stent insertions were well tolerated. Magnesium stents migrated in six rabbits (one at 1 week, one at 2 weeks and four at 4 weeks), and plastic stents migrated in three rabbits (one at 2 weeks and two at 4 weeks; p > 0.05). Esophageal wall remodeling (thinner epithelial and smooth muscle layers) was similar in both stented groups (p > 0.05), and the esophagus wall was found to be significantly thinner in the stented groups than in the control group (p < 0.05). Esophageal injury and collagen deposition following stent insertion were similar and did not differ from the control group (p > 0.05). Esophageal silicone-covered magnesium stents provided reliable support for at least 2 weeks, with acceptable migration rates and without causing severe injury or tissue reaction compared with plastic stents.

  17. Silicone-covered biodegradable magnesium-stent insertion in the esophagus: a comparison with plastic stents

    PubMed Central

    Zhu, Yue-Qi; Yang, Kai; Edmonds, Laura; Wei, Li-Ming; Zheng, Reila; Cheng, Ruo-Yu; Cui, Wen-Guo; Cheng, Ying-Sheng

    2016-01-01

    Background: We determined the feasibility of, and tissue response to silicone-covered biodegradable magnesium- and plastic-stent insertion into the esophagus in rabbits. Methods: The mechanical compression–recovery characteristics and degradation behaviors of the magnesium stent were investigated in vitro. A total of 45 rabbits were randomly divided into a magnesium- (n = 15) and a plastic- (n = 15) stent group, and underwent stent insertion into the lower third of the esophagus under fluoroscopic guidance; a control group (n = 15) did not undergo the intervention. Esophagography was performed at 1, 2, and 4 weeks. Five rabbits in each group were euthanized at each time point for histological examination. Results: Silicone-covered magnesium stents showed similar radial force to plastic stents (p > 0.05). The magnesium stents degraded rapidly in an acidic solution, but 90.2% ± 3.1% of the residual mass was maintained after a 2-week degradation in a solution with a pH of 4.0. All stent insertions were well tolerated. Magnesium stents migrated in six rabbits (one at 1 week, one at 2 weeks and four at 4 weeks), and plastic stents migrated in three rabbits (one at 2 weeks and two at 4 weeks; p > 0.05). Esophageal wall remodeling (thinner epithelial and smooth muscle layers) was similar in both stented groups (p > 0.05), and the esophagus wall was found to be significantly thinner in the stented groups than in the control group (p < 0.05). Esophageal injury and collagen deposition following stent insertion were similar and did not differ from the control group (p > 0.05). Conclusions: Esophageal silicone-covered magnesium stents provided reliable support for at least 2 weeks, with acceptable migration rates and without causing severe injury or tissue reaction compared with plastic stents. PMID:28286555

  18. Potassium nickel hexacyanoferrate as a high-voltage cathode material for nonaqueous magnesium-ion batteries

    NASA Astrophysics Data System (ADS)

    Chae, Munseok S.; Hyoung, Jooeun; Jang, Minchul; Lee, Hochun; Hong, Seung-Tae

    2017-09-01

    The magnesium insertion capability of Prussian blue (PB) analogue, potassium nickel hexacyanoferrate K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-086), is demonstrated as a cathode material for rechargeable magnesium-ion batteries using a conventional organic electrolyte. K1.51Ni[Fe(CN)6]0.954(H2O)0.766 is synthesized first, and potassium ions are electrochemically extracted to prepare the KNF-086 cathode. The electrochemical test cell is composed of KNF-086 as the working electrode, an activated carbon as the counter and reference electrode, and 0.5 M Mg(ClO4)2 in acetonitrile as the electrolyte. The cell shows a reversible magnesium insertion/extraction reaction with a discharge capacity of 48.3 mAh g-1 at a 0.2 C rate, and an average discharge voltage at 2.99 V (vs. Mg/Mg2+) that is the highest among the cathode materials ever reported for magnesium-ion batteries. Elemental analysis and Fourier electron-density map analysis from powder X-ray diffraction data confirm that the magnesium-inserted phase is Mg0.27K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (MKNF-086), and the magnesium ions in MKNF-086 are positioned at the center of the large interstitial cavities of cubic PB. Compared to KNF-086, MKNF-086 exhibits a decreased unit cell parameter (0.8%) and volume (2.4%). These results demonstrate that a PB analogue, potassium nickel hexacyanoferrate, could be utilized as a potential cathode material for conventional organic electrolyte-based magnesium-ion batteries.

  19. Study of second phase in bioabsorbable magnesium alloys: Phase stability evaluation via Dmol{sup 3} calculation

    SciTech Connect

    Yang, Huazhe; Liu, Chen; Wan, Peng; Tan, Lili; Yang, Ke

    2013-11-01

    Thermodynamical stabilities of four conventional second phases as well as magnesium matrix in bioabsorbable magnesium alloys were investigated theoretically via computer calculation method. Model of individual phase and systems including phase and four water molecular (phase-4H{sub 2}O) were established to simulate the in vitro and in vivo environment. Local orbital density functional theory approach was applied to calculate the total energy for the individual phase and phase-4H{sub 2}O system. The results demonstrated that all the second phases possessed higher phase stability compared with magnesium matrix, but the phase stability was quite different for different types of second phases or second phase-4H{sub 2}O systems. Furthermore, a schematic process of inflammation reaction caused by magnesium alloy implants was proposed for the further evaluation on biocompatibility of different second phases.

  20. Room temperature magnesium electrorefining by using non-aqueous electrolyte

    NASA Astrophysics Data System (ADS)

    Park, Jesik; Jung, Yeojin; Kusumah, Priyandi; Dilasari, Bonita; Ku, Heesuk; Kim, Hansu; Kwon, Kyungjung; Lee, Churl Kyoung

    2016-09-01

    The increasing usage of magnesium inevitably leads to a fast increase in magnesium scrap, and magnesium recycling appears extremely beneficial for cost reduction, preservation of natural resources and protection of the environment. Magnesium refining for the recovery of high purity magnesium from metal scrap alloy (AZ31B composed of magnesium, aluminum, zinc, manganese and copper) at room temperature is investigated with a non-aqueous electrolyte (tetrahydrofuran with ethyl magnesium bromide). A high purity (99.999%) of electrorefined magneisum with a smooth and dense surface is obtained after potentiostatic electrolysis with an applied voltage of 2 V. The selective dissolution of magnesium from magnesium alloy is possible by applying an adequate potential considering the tolerable impurity level in electrorefined magnesium and processing time. The purity estimation method suggested in this study can be useful in evaluating the maximum content of impurity elements.

  1. Structure and compatibility of a magnesium electrolyte with a sulphur cathode.

    PubMed

    Kim, Hee Soo; Arthur, Timothy S; Allred, Gary D; Zajicek, Jaroslav; Newman, John G; Rodnyansky, Alexander E; Oliver, Allen G; Boggess, William C; Muldoon, John

    2011-08-09

    Magnesium metal is an ideal rechargeable battery anode material because of its high volumetric energy density, high negative reduction potential and natural abundance. Coupling Mg with high capacity, low-cost cathode materials such as electrophilic sulphur is only possible with a non-nucleophilic electrolyte. Here we show how the crystallization of the electrochemically active species formed from the reaction between hexamethyldisilazide magnesium chloride and aluminum trichloride enables the synthesis of a non-nucleophilic electrolyte. Furthermore, crystallization was essential in the identification of the electroactive species, [Mg(2)(μ-Cl)(3)·6THF](+), and vital to improvements in the voltage stability and coulombic efficiency of the electrolyte. X-ray photoelectron spectroscopy analysis of the sulphur electrode confirmed that the electrochemical conversion between sulphur and magnesium sulfide can be successfully performed using this electrolyte.

  2. Structure and compatibility of a magnesium electrolyte with a sulphur cathode

    PubMed Central

    Kim, Hee Soo; Arthur, Timothy S.; Allred, Gary D.; Zajicek, Jaroslav; Newman, John G.; Rodnyansky, Alexander E.; Oliver, Allen G.; Boggess, William C.; Muldoon, John

    2011-01-01

    Magnesium metal is an ideal rechargeable battery anode material because of its high volumetric energy density, high negative reduction potential and natural abundance. Coupling Mg with high capacity, low-cost cathode materials such as electrophilic sulphur is only possible with a non-nucleophilic electrolyte. Here we show how the crystallization of the electrochemically active species formed from the reaction between hexamethyldisilazide magnesium chloride and aluminum trichloride enables the synthesis of a non-nucleophilic electrolyte. Furthermore, crystallization was essential in the identification of the electroactive species, [Mg2(μ-Cl)3·6THF]+, and vital to improvements in the voltage stability and coulombic efficiency of the electrolyte. X-ray photoelectron spectroscopy analysis of the sulphur electrode confirmed that the electrochemical conversion between sulphur and magnesium sulfide can be successfully performed using this electrolyte. PMID:21829189

  3. Effect of magnesium addition on the wetting of alumina by aluminium

    NASA Astrophysics Data System (ADS)

    Sangghaleh, Ali; Halali, Mohammad

    2009-07-01

    In this report the wetting behaviour between polycrystalline alumina substrates and molten aluminium doped with magnesium as a wetting agent has been studied using the sessile drop technique. The time required for equilibrium attainment is investigated. To explore the formation of possible phases at the interface, electron microscopic studies along with EDX analysis have been employed. It is found that magnesium reduces the time and temperature required for equilibrium in the Al/Al 2O 3 system. The Al-7 wt% Mg and Al-10 wt% Mg alloys can wet alumina at temperatures as low as 900 °C. It is also found that molten aluminium doped with magnesium can wet polycrystalline alumina at temperatures below 1000 °C. A thin reaction layer was observed at the Al-Mg/Al 2O 3 interface in the present study.

  4. Massive magnesium depletion and isotope fractionation in weathered basalts

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Ming; Teng, Fang-Zhen; Rudnick, Roberta L.; McDonough, William F.; Cummings, Michael L.

    2014-06-01

    Magnesium isotopes have been shown to fractionate significantly during continental weathering, however, the degree and direction of fractionation varies from one study to the next, and the main factors that control Mg isotope fractionation during weathering have yet to be delineated. Here, we report Mg contents and isotopic compositions for two ∼10 m deep drill cores through bauxites developed on Columbia River Basalts (CRBs). Samples from these two drill cores have very low MgO contents (0.12-0.25 wt.%) and variable but high δ26Mg values (from -0.1 to up to +1.8, the heaviest isotopic composition ever reported for Mg) relative to the average values of fresh CRBs (δ26Mg = -0.23 ± 0.07 and MgO = 5.9 wt.%). These features reflect the near complete loss of Mg in the isotopically heavy regolith. The most highly weathered bauxites at the tops of the profiles have the lowest δ26Mg values, reflecting the addition of isotopically light eolian dust. Excluding these samples, δ26Mg in bauxites displays a weak, positive correlation with gibbsite abundance, suggesting that gibbsite preferentially retains 26Mg in the bauxites. The integrated Mg isotopic fractionation factors between bauxite and fluid (Δ26Mgbauxite-fluid), inferred from Rayleigh fractionation calculations, vary from 0.05‰ to 0.4‰, which is similar to the range inferred from previous studies of igneous rock weathering profiles, though none of these previous studies found the extremely heavy δ26Mg and massive Mg depletion seen here. Collectively, studies of weathering profiles suggest loss of isotopically light Mg from the continents, which must contribute to the very light δ26Mg seen in river water and seawater.

  5. Magnesium isotope fractionation in silicate melts by chemical and thermal diffusion

    NASA Astrophysics Data System (ADS)

    Richter, Frank M.; Watson, E. Bruce; Mendybaev, Ruslan A.; Teng, Fang-Zhen; Janney, Philip E.

    2008-01-01

    Two types of laboratory experiments were used to quantify magnesium isotopic fractionations associated with chemical and thermal (Soret) diffusion in silicate liquids. Chemical diffusion couples juxtaposing a molten natural basalt (SUNY MORB) and a molten natural rhyolite (Lake County Obsidian) were run in a piston cylinder apparatus and used to determine the isotopic fractionation of magnesium as it diffused from molten basalt to molten rhyolite. The thermal diffusion experiments were also run in a piston cylinder apparatus but with a sample made entirely of molten SUNY MORB displaced from the hotspot of the assembly furnace so that the sample would have a temperature difference of about 100-200 °C from one end to the other. The chemical diffusion experiments showed fractionations of 26Mg/ 24Mg by as much as 7‰, which resulted in an estimate for the mass dependence of the self-diffusion coefficients of the magnesium isotopes corresponding to D/D=(24/26)β with β = 0.05. The thermal diffusion experiments showed that a temperature difference of about 100 °C resulted in the MgO, CaO, and FeO components of the basalt becoming slightly enriched by about 1 wt% in the colder end while SiO 2 was enriched by several wt% in the hotter end. The temperature gradient also fractionated the magnesium isotopes. A temperature difference of about 150 °C produced an 8‰ enrichment of 26Mg/ 24Mg at the colder end relative to the hotter end. The magnesium isotopic fractionation as a function of temperature in molten basalt corresponds to 3.6 × 10 -2‰/°C/amu.

  6. Magnesium in North America: A Changing Landscape

    NASA Astrophysics Data System (ADS)

    Slade, Susan

    The changing landscape of North American manufacturing in the context of global competition is impacting the market of all raw materials, including magnesium. Current automotive fuel economy legislation and pending legislation on the emissions of greenhouse gases are impacting magnesium's largest consuming industries, such as aluminum, automotive components, steel and transition metals. These industries are all considering innovative ways to efficiently incorporate the needed raw materials into their processes. The North American magnesium market differs from other regions based on maturity, supply streams, changing manufacturing capabilities and trade cases, combined with the transformation of North American manufacturing.

  7. Three separate proteins constitute the magnesium chelatase of Rhodobacter sphaeroides.

    PubMed

    Willows, R D; Gibson, L C; Kanangara, C G; Hunter, C N; von Wettstein, D

    1996-01-15

    The insertion of magnesium into protoporphyrin IX is the first step unique to chlorophyll production and is catalyzed by magnesium chelatase. The Rhodobacter sphaeroides genes, bchI and bchD together, and bchH alone, were cloned and expressed with the pET3a vector in Escherichia coli strain BL21 (DE3). The 40-kDa BchI protein was synthesized in greater abundance compared to the 70-kDa BchD protein when both were expressed together from the same plasmid. The production of large amounts of the 140-kDa BchH protein in E. coli was accompanied by an accumulation of protoporphyrin IX. The accumulated protoporphyrin IX was bound specifically to BchH in an approximate molar ratio of 1:1. All three recombinant proteins were soluble; BchH was monomeric, Bchl was dimeric, while BchD appeared to be polymeric with a molecular mass of approximately 550 kDa. The BchH and BchI proteins were purified to apparent homogeneity while BchD was separated from BchI and partially purified. Magnesium was inserted into protoporphyrin IX and deuteroporphyrin by combining these three proteins in the presence of ATP. One monomer of BchH to one dimer of BchI gave the optimal magnesium chelatase activity and the activity was dependent on the amount of partially purified BchD added to the assay at the optimum BchH:BchI ratio. The reaction was dissected into two parts with an activation step requiring BchI, BchD, and Mg2+-ATP, and a metal-insertion step which in addition requires Mg2+, protoporphyrin IX, and BchH. The stoichiometric binding of protoporphyrin IX to BchH in vitro is direct evidence for BchH carrying out such a role in vivo whereas the other two proteins are involved in ATP activation and magnesium insertion.

  8. Magnesium modulates the expression levels of calcification-associated factors to inhibit calcification in a time-dependent manner.

    PubMed

    Xu, Jinsheng; Bai, Yaling; Jin, Jingjing; Zhang, Junxia; Zhang, Shenglei; Cui, Liwen; Zhang, Huiran

    2015-03-01

    Vascular calcification, a common complication in patients with chronic kidney disease, involves a variety of mechanisms associated with the regulation of calcification-associated factors. Previous clinical studies have indicated that magnesium is involved in the reduction of vascular calcification; however, the mechanism underlying this process remains unknown. The aim of the present study was to investigate the effects of magnesium on β-glycerophosphate (β-GP)-induced calcification and the underlying mechanisms. Primary rat vascular smooth muscle cells (VSMCs) were exposed to 10 mM β-GP in medium with or without the addition of 3 mM magnesium or 2-aminoethoxy-diphenylborate (2-APB; an inhibitor of magnesium transport), for a 14-day period. Calcium deposition and alkaline phosphatase (ALP) activity were measured by Alizarin red staining, quantification of calcium and enzyme-linked immunosorbent assay. The expression levels of core-binding factor α-1 (Cbfα1), matrix Gla protein (MGP) and osteopontin (OPN) were determined by reverse transcription-polymerase chain reaction or western blot analysis, following incubation for 0, 3, 6, 10 and 14 days with the different media. VSMC calcification and ALP activity was reduced significantly in the high-magnesium medium compared with the calcification medium, during the 14-day incubation. The magnesium-induced changes in the VSMCs included a β-GP-induced downregulation of Cbfα1 by day 3 of incubation, an effect that was gradually enhanced over the 14-day period. By contrast, magnesium produced notable increases in MGP and OPN expression levels, with an opposite pattern to that observed in the Cbfα1 expression levels. However, the addition of 2-APB appeared to inhibit the protective effect of magnesium on the VSMCs. Therefore, magnesium was able to effectively reduce β-GP-induced calcification in rat VSMCs by regulating the expression levels of calcification-associated factors in a time-dependent manner.

  9. Boron Clusters as Highly Stable Magnesium-Battery Electrolytes**

    PubMed Central

    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 electrolytes is very high. PMID:24519845

  10. Development and validation of simple titrimetric method for the determination of magnesium content in esomeprazole magnesium.

    PubMed

    Haddadin, R N; Issa, A Y

    2011-07-01

    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.

  11. Development and Validation of Simple Titrimetric Method for the Determination of Magnesium Content in Esomeprazole Magnesium

    PubMed Central

    Haddadin, R. N.; Issa, A. Y.

    2011-01-01

    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. PMID:22707837

  12. Increased anthocyanin accumulation in aster flowers at elevated temperatures due to magnesium treatment.

    PubMed

    Shaked-Sachray, Liat; Weiss, David; Reuveni, Moshe; Nissim-Levi, Ada; Oren-Shamir, Michal

    2002-04-01

    Temperature is one of the main external factors affecting anthocyanin accumulation in plant tissues: low temperatures cause an increase and elevated temperatures cause a decrease in anthocyanin concentration. Several metals have been shown to increase the half-life time of anthocyanins, by forming complexes with them. We studied the combined effect of elevated temperatures and increased metal concentrations on the accumulation of anthocyanins in aster 'Sungal' flowers. It has been found that magnesium treatment of aster plants or detached flower buds, partially prevents colour fading at elevated temperatures. Anthocyanin concentration of aster 'Sungal' flowers grown at 29 degrees C/21 degrees C day/night, respectively, was about half that of flowers grown at 17 degrees C/9 degrees C. The activity of phenylalanine ammonia-lyase (PAL) and chalcone isomerase (CHI) decreased as the temperature increased. Treatment of both whole plants and detached flower buds grown at elevated temperatures in the presence of magnesium salts, increased flower anthocyanin concentration by up to 80%. Measurement of magnesium following these treatments revealed an increased level of the metal in the petals, suggesting a direct effect. Magnesium treatment does not seem to cause increased synthesis of anthocyanin through a stress-related reaction, since the activities of both PAL and CHI did not increase due to this treatment. The results of this study show that increasing magnesium levels in aster petals prevents the deleterious effect of elevated temperatures on anthocyanin accumulation, thus enhancing flower colour.

  13. Unusual behavior in magnesium-copper cluster matter produced by helium droplet mediated deposition

    SciTech Connect

    Emery, S. B. Little, B. K.; Xin, Y.; Ridge, C. J.; Lindsay, C. M.; Buszek, R. J.; Boatz, J. A.; Boyle, J. M.

    2015-02-28

    We demonstrate the ability to produce core-shell nanoclusters of materials that typically undergo intermetallic reactions using helium droplet mediated deposition. Composite structures of magnesium and copper were produced by sequential condensation of metal vapors inside the 0.4 K helium droplet baths and then gently deposited onto a substrate for analysis. Upon deposition, the individual clusters, with diameters ∼5 nm, form a cluster material which was subsequently characterized using scanning and transmission electron microscopies. Results of this analysis reveal the following about the deposited cluster material: it is in the un-alloyed chemical state, it maintains a stable core-shell 5 nm structure at sub-monolayer quantities, and it aggregates into unreacted structures of ∼75 nm during further deposition. Surprisingly, high angle annular dark field scanning transmission electron microscopy images revealed that the copper appears to displace the magnesium at the core of the composite cluster despite magnesium being the initially condensed species within the droplet. This phenomenon was studied further using preliminary density functional theory which revealed that copper atoms, when added sequentially to magnesium clusters, penetrate into the magnesium cores.

  14. Formation and evaluation of protective layer over magnesium melt under various gaseous atmospheres

    NASA Astrophysics Data System (ADS)

    Emami, Samar

    Molten magnesium exposed to an atmosphere of air will oxidize rapidly, resulting in burning on the metal surface, melt loss and handling difficulties. If magnesium is to be used as a casting metal, the melt must be protected from this severe oxidation. The objective of this work was to study the oxidation of molten magnesium in various protective atmospheres to obtain qualitative and quantitative data on the rate and mechanism of protection. Measurements of the kinetics of the protective layer formation in various atmospheres, additive gas concentrations in air and temperatures were made by monitoring the weight gain of the samples with time. To obtain knowledge of magnesium melt protection and to find the best practical protection condition, samples were examined in atmospheres of SF6/air, CO2/air, SO2/air, and SF6/CO2/air. Experiments were performed using a thermo-gravimetric analysis (TGA) unit in the temperature range of 670 - 770°C (943 - 1043K). Reaction times of 2, 3 and 7 minutes were selected to have the closest condition to that of industry. The morphology, chemical composition and thickness of the surface films were studied using SEM/EDS and a kinetic model for the process was developed. Results showed that all the additives contributed to protection of molten magnesium. Among them, SF6 and SO2 showed best protection by forming a denser and more uniform surface film. However, the use of SO 2 is not recommended due to the violent behavior observed at longer times and higher temperatures. In addition, there are some drawbacks due to its high toxicity and corrosiveness, which demand additional handling and ventilation procedures. Despite the requirement of a higher concentration in air, CO2 showed the lowest protection capabilities among all. However, addition of small amount of CO2 to a mixture of SF 6 and air revealed a high inhibiting effect to molten magnesium. The effects of additive concentration, temperature and reaction time were further

  15. Magnesium Recycling of Partially Oxidized, Mixed Magnesium-Aluminum Scrap through Combined Refining and Solid Oxide Membrane Electrolysis Processes

    SciTech Connect

    Xiaofei Guan; Peter A. Zink; Uday B. Pal; Adam C. Powell

    2012-01-01

    Pure magnesium (Mg) is recycled from 19g of partially oxidized 50.5wt.% Mg-Aluminum (Al) alloy. During the refining process, potentiodynamic scans (PDS) were performed to determine the electrorefining potential for magnesium. The PDS show that the electrorefining potential increases over time as the magnesium content inside the Mg-Al scrap decreases. Up to 100% percent of magnesium is refined from the Mg-Al scrap by a novel refining process of dissolving magnesium and its oxide into a flux followed by vapor phase removal of dissolved magnesium and subsequently condensing the magnesium vapor. The solid oxide membrane (SOM) electrolysis process is employed in the refining system to enable additional recycling of magnesium from magnesium oxide (MgO) in the partially oxidized Mg-Al scrap. The combination of the refining and SOM processes yields 7.4g of pure magnesium.

  16. Magnesium Recycling of Partially Oxidized, Mixed Magnesium-Aluminum Scrap through Combined Refining and Solid Oxide Membrane (SOM) Electrolysis Processes

    NASA Astrophysics Data System (ADS)

    Guan, Xiaofei; Zink, Peter; Pal, Uday

    Pure magnesium (Mg) is recycled from 19g of partially oxidized 50.5 wt.%Mg-Aluminum (Al) alloy. During the refining process, potentiodynamic scans (PDS) were performed to determine the electrorefining potential for magnesium. The PDS show that the electrorefining potential increases over time as the Mg content inside the Mg-Al scrap decreases. Up to 100% percent of magnesium is refined from the Mg-Al scrap by a novel refining process of dissolving magnesium and its oxide into a flux followed by vapor phase removal of dissolved magnesium and subsequently condensing the magnesium vapors in a separate condenser. The solid oxide membrane (SOM) electrolysis process is employed in the refining system to enable additional recycling of magnesium from magnesium oxide (MgO) in the partially oxidized Mg-Al scrap. The combination of the refining and SOM processes yields 7.4g of pure magnesium; could not collect and weigh all of the magnesium recovered.

  17. Magnesium Recycling of Partially Oxidized, Mixed Magnesium-Aluminum Scrap Through Combined Refining and Solid Oxide Membrane (SOM) Electrolysis Processes

    SciTech Connect

    Guan, Xiaofei; Zink, Peter; Pal, Uday

    2012-03-11

    Pure magnesium (Mg) is recycled from 19g of partially oxidized 50.5wt.%Mg-Aluminum (Al) alloy. During the refining process, potentiodynamic scans (PDS) were performed to determine the electrorefining potential for magnesium. The PDS show that the electrorefining potential increases over time as the Mg content inside the Mg-Al scrap decreases. Up to 100% percent of magnesium is refined from the Mg-Al scrap by a novel refining process of dissolving magnesium and its oxide into a flux followed by vapor phase removal of dissolved magnesium and subsequently condensing the magnesium vapors in a separate condenser. The solid oxide membrane (SOM) electrolysis process is employed in the refining system to enable additional recycling of magnesium from magnesium oxide (MgO) in the partially oxidized Mg-Al scrap. The combination of the refining and SOM processes yields 7.4g of pure magnesium; could not collect and weigh all of the magnesium recovered.

  18. Magnesium levels in critically ill patients. What should we measure?

    PubMed

    Huijgen, H J; Soesan, M; Sanders, R; Mairuhu, W M; Kesecioglu, J; Sanders, G T

    2000-11-01

    We studied the relation between ionized magnesium, total magnesium, and albumin levels in serum of 115 critically ill patients and the role of extracellular and intracellular magnesium in outcome prediction. Levels of serum total and ionized magnesium, serum albumin, and magnesium in mononuclear blood cells and erythrocytes were measured and the APACHE II score and 1-month mortality recorded. Of all patients, 51.3% had a serum total magnesium concentration below the reference range. In 71% of these hypomagnesemic patients, a normal serum ionized magnesium concentration was measured. None of the patients had an intracellular magnesium concentration below the reference limit. Except for serum total and ionized magnesium, none of the magnesium parameters correlated significantly with each other. A significantly negative correlation was found between serum albumin and the fraction ionized magnesium. There was no association between low extracellular or intracellular magnesium and clinical outcome. The observation of hypomagnesemia in critically ill patients depends on which magnesium fraction is measured. The lack of correlation with clinical outcome suggests hypomagnesemia to be merely an epiphenomenon. Reliable concentrations of serum ionized magnesium can be obtained only by direct measurement and not by calculation from serum total magnesium and albumin.

  19. Magnesium isotope fractionation during continental weathering

    NASA Astrophysics Data System (ADS)

    Teng, F. Z.; Huang, K. J.; Li, W.; Liu, X. M.; Ma, L.

    2014-12-01

    Continental weathering links the atmosphere, hydrosphere and continents as it regulates the CO2 content of the atmosphere, shifts the composition of the continental crust from basaltic to andesitic, and ultimately controls the chemical composition of river waters and seawater. Magnesium is a water-soluble major element in the hydrosphere, continental crust and the mantle, and has three stable isotopes (24Mg, 25Mg and 26Mg). Studies of Mg isotopes during continental weathering may help to document the interactions between hydrosphere, crust and mantle. Previous studies have shown that the continental crust has a heterogeneous but on average heavier Mg isotopic composition than the mantle, whereas the hydrosphere is isotopically light. The complementary characteristics of Mg isotopic compositions between continental and hydrosphere have been attributed to continental weathering, with light Mg isotopes partitioned into water, leaving heavy Mg isotopes behind in the crustal residue. Here we summarize our studies of Mg isotope fractionation in four weathering profiles under various climate conditions. We show that large Mg isotope fractionation can occur during continental weathering. Although the weathered residue is usually enriched in heavier Mg isotopes than unaltered parent rocks, some heavily weathered products can be quite light in Mg isotopic composition. The complicated behaviors of Mg isotopes reflect different control factors during weathering such as parent rock lithology, primary mineral dissolution, secondary mineral formation, ion exchange, vegetation uptake etc. Though studies of natural samples can provide direct evidence on isotope fractionation, more well-controlled laboratory experiments on Mg isotope fractionation between fluids and minerals are needed in order to fully understand the behaviors of Mg isotopes during weathering, which ultimately lays the foundation for making Mg isotope geochemistry an important tool for studying different geological

  20. Magnesium stable isotope ecology using mammal tooth enamel

    NASA Astrophysics Data System (ADS)

    Martin, Jeremy E.; Vance, Derek; Balter, Vincent

    2015-01-01

    Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ26Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ26Mg, δ13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ26Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this 26Mg enrichment up the trophic chain is due to a 26Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ26Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages.

  1. Magnesium stable isotope ecology using mammal tooth enamel

    PubMed Central

    Martin, Jeremy E.; Vance, Derek; Balter, Vincent

    2015-01-01

    Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ26Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ26Mg, δ13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ26Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this 26Mg enrichment up the trophic chain is due to a 26Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ26Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages. PMID:25535375

  2. Magnesium stable isotope ecology using mammal tooth enamel.

    PubMed

    Martin, Jeremy E; Vance, Derek; Balter, Vincent

    2015-01-13

    Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ(13)C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ(44)Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ(26)Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ(26)Mg, δ(13)C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ(26)Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this (26)Mg enrichment up the trophic chain is due to a (26)Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ(26)Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ(26)Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages.

  3. Nuclear reactor shield including magnesium oxide

    DOEpatents

    Rouse, Carl A.; Simnad, Massoud T.

    1981-01-01

    An improvement in nuclear reactor shielding of a type used in reactor applications involving significant amounts of fast neutron flux, the reactor shielding including means providing structural support, neutron moderator material, neutron absorber material and other components as described below, wherein at least a portion of the neutron moderator material is magnesium in the form of magnesium oxide either alone or in combination with other moderator materials such as graphite and iron.

  4. Cold Spray Aluminum for Magnesium Gearbox Repair

    DTIC Science & Technology

    2008-02-01

    Cold Spray Aluminum for Magnesium Gearbox Repair Phillip F Leyman . US Army Research Laboratory Weapons & Materials Research Directorate...AND SUBTITLE Cold Spray Aluminum for Magnesium Gearbox Repair 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...tirogram ec ves • Develop the densest, thinnest, most corrosion resistant Aluminum -based Cold Spray coating ith th t t dh i b d t th tw e grea es

  5. Magnesium-titanium alloys for biomedical applications

    NASA Astrophysics Data System (ADS)

    Hoffmann, Ilona

    Magnesium has been identified as a promising biodegradable implant material because it does not cause systemic toxicity and can reduce stress shielding. However, it corrodes too quickly in the body. Titanium, which is already used ubiquitously for implants, was chosen as the alloying element because of its proven biocompatibility and corrosion resistance in physiological environments. Thus, alloying magnesium with titanium is expected to improve the corrosion resistance of magnesium. Mg-Ti alloys with a titanium content ranging from 5 to 35 at.-% were successfully synthesized by mechanical alloying. Spark plasma sintering was identified as a processing route to consolidate the alloy powders made by ball-milling into bulk material without destroying the alloy structure. This is an important finding as this metastable Mg-Ti alloy can only be heated up to max. 200C° for a limited time without reaching the stable state of separated magnesium and titanium. The superior corrosion behavior of Mg 80-Ti20 alloy in a simulated physiological environment was shown through hydrogen evolution tests, where the corrosion rate was drastically reduced compared to pure magnesium and electrochemical measurements revealed an increased potential and resistance compared to pure magnesium. Cytotoxicity tests on murine pre-osteoblastic cells in vitro confirmed that supernatants made from Mg-Ti alloy were no more cytotoxic than supernatants prepared with pure magnesium. Mg and Mg-Ti alloys can also be used to make novel polymer-metal composites, e.g., with poly(lactic-co-glycolic acid) (PLGA) to avoid the polymer's detrimental pH drop during degradation and alter its degradation pattern. Thus, Mg-Ti alloys can be fabricated and consolidated while achieving improved corrosion resistance and maintaining cytocompatibility. This work opens up the possibility of using Mg-Ti alloys for fracture fixation implants and other biomedical applications. KEYWORDS: Magnesium, titanium, corrosion

  6. Highly specific spectrophotometric method for palladium(II) determination with 3-(5'-tetrazolylazo)-2,6-Diaminotoluene in the presence of chlorides. Kinetic and equilibrium study of reactions.

    PubMed

    Hernández, O; Jiménez, A I; Jiménez, F; Arias, J J; Havel, J

    1994-05-01

    3-(5'-tetrazolylazo)-2,6-Diaminotoluene (TEADAT, H(3)L(2+)) forms stable 1:1 and 1:2 (metal:ligand) pink-red complexes (lambda(max) 506 and 536 nm) with palladium(II). The apparent molar absorptivity of 1:2 complex is 5.2 x 10(4) 1.mol(-1). cm(-1) at 536 nm. Equilibrium constants beta*(nl) for reactions PdCl(2-)(4) + nH(3)L(2+) right harpoon over left harpoonright harpoon over left harpoon PdCl(4-n) (H(2)L)(2n-2)(n) + n Cl(-) + n H(+) were determined: logbeta*(1) = 4.09 +/- 0.05, logbeta*(2) = 8.40 +/- 0.02, corresponding stability conditional constants of PdCl(3)(H(2)L) and PdCl(2)(H(2)L)(2+)(2) were log beta(1) = 19.03, log beta(2) = 26.74. The formation of complexes was rather slow but could be speeded up considerably by the catalytic effect of trace amounts of thiocyanate. Constant absorbance values were thus reached in 2-5 min. A rapid, sensitive and highly specific method for the determination of palladium(II) at pH 1.42 in 0.25M NACl has been worked out with a detection limit of 0.54 mug. Interference of precious and common metal ions have been studied and the method has been applied for the determination of palladium in Pd asbestos, oakay alloys and various catalysts and for the determination of palladium in precious metals.

  7. Immunological Response to Biodegradable Magnesium Implants

    NASA Astrophysics Data System (ADS)

    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.

  8. Experimental study of the astrophysically important Na23(α,p)Mg26 and Na23(α,n)Al26 reactions

    SciTech Connect

    Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.; Ayangeakaa, A. D.; Dickerson, C.; Hoffman, C. R.; Jiang, C. L.; Kay, B. P.; Lai, J.; Nusair, O.; Pardo, R. C.; Santiago-Gonzalez, D.; Talwar, R.; Ugalde, C.

    2016-12-19

    The 23Na(α,p) 26Mg and 23Na(α,n) 26Al reactions are important for our understanding of the 26Al abundance in massive stars. The aim of this work is to report on a direct and simultaneous measurement of these astrophysically important reactions using an active target system. The reactions were investigated in inverse kinematics using 4He as the active target gas in the detector. We measured the excitation functions in the energy range of about 2 to 6 MeV in the center of mass. We have found that the cross sections of the 23Na(α,p) 26Mg and the 23Na(α,n) 26Al reactions are in good agreement with previous experiments and with statistical-model calculations. As a result, the astrophysical reaction rate of the 23Na(α,n) 26Al reaction has been reevaluated and it was found to be larger than the recommended rate.

  9. Elucidating the role of the TRPM7 alpha-kinase: TRPM7 kinase inactivation leads to magnesium deprivation resistance phenotype in mice

    PubMed Central

    Ryazanova, Lillia V.; Hu, Zhixian; Suzuki, Sayuri; Chubanov, Vladimir; Fleig, Andrea; Ryazanov, Alexey G.

    2014-01-01

    TRPM7 is an unusual bi-functional protein containing an ion channel covalently linked to a protein kinase domain. TRPM7 is implicated in regulating cellular and systemic magnesium homeostasis. While the biophysical properties of TRPM7 ion channel and its function are relatively well characterized, the function of the TRPM7 enzymatically active kinase domain is not understood yet. To investigate the physiological role of TRPM7 kinase activity, we constructed mice carrying an inactive TRPM7 kinase. We found that these mice were resistant to dietary magnesium deprivation, surviving three times longer than wild type mice; also they displayed decreased chemically induced allergic reaction. Interestingly, mutant mice have lower magnesium bone content compared to wild type mice when fed regular diet; unlike wild type mice, mutant mice placed on magnesium-depleted diet did not alter their bone magnesium content. Furthermore, mouse embryonic fibroblasts isolated from TRPM7 kinase-dead animals exhibited increased resistance to magnesium deprivation and oxidative stress. Finally, electrophysiological data revealed that the activity of the kinase-dead TRPM7 channel was not significantly altered. Together, our results suggest that TRPM7 kinase is a sensor of magnesium status and provides coordination of cellular and systemic responses to magnesium deprivation. PMID:25534891

  10. Magnesium-phosphate-glass cements with ceramic-type properties

    DOEpatents

    Sugama, T.; Kukacka, L.E.

    1982-09-23

    Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate, exhibits rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

  11. Magnesium phosphate glass cements with ceramic-type properties

    SciTech Connect

    Sugama, T.; Kukacka, L.E.

    1984-03-13

    Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate exhibiting rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono-and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

  12. Magnesium phosphate glass cements with ceramic-type properties

    DOEpatents

    Sugama, Toshifumi; Kukacka, Lawrence E.

    1984-03-13

    Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate exhibiting rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

  13. Gestational magnesium deficiency is deleterious to fetal outcome.

    PubMed

    Almonte, R A; Heath, D L; Whitehall, J; Russell, M J; Patole, S; Vink, R

    1999-07-01

    A number of recent epidemiological findings have implicated magnesium as being essential to fetal well-being. Few studies, however, have examined the relationship between maternal requirements for dietary magnesium and subsequent mortality and morbidity in offspring. The present study uses a rodent model of dietary-induced hypomagnesemia to investigate the effects of magnesium deficiency prior to and during gestation on neonatal morbidity and mortality. Magnesium deficiency during gestation significantly increased neonatal mortality and morbidity. Such increases were associated with a reduced free magnesium concentration in both maternal and offspring blood and an increased incidence of periventricular hemorrhage and edema in newborn pups as observed by magnetic resonance imaging and histology. Animals fed a magnesium-deficient diet before mating but given magnesium supplementation during gestation did not demonstrate a significant change in neonatal mortality and morbidity when compared to control animals. The significant improvement in fetal outcome with dietary magnesium supports the concept of magnesium supplementation during pregnancy.

  14. The Effect of Adding Corrosion Inhibitors into an Electroless Nickel Plating Bath for Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Hu, Rong; Su, Yongyao; Liu, Hongdong; Cheng, Jiang; Yang, Xin; Shao, Zhongcai

    2016-10-01

    In this work, corrosion inhibitors were added into an electroless nickel plating bath to realize nickel-phosphorus (Ni-P) coating deposition on magnesium alloy directly. The performance of five corrosion inhibitors was evaluated by inhibition efficiency. The results showed that only ammonium hydrogen fluoride (NH4HF2) and ammonium molybdate ((NH4)2MoO4) could be used as corrosion inhibitors for magnesium alloy in the bath. Moreover, compounding NH4HF2 and (NH4)2MoO4, the optimal concentrations were both at 1.5 ~ 2%. The deposition process of Ni-P coating was observed by using a scanning electron microscope (SEM). It showed corrosion inhibitors inhibited undesired dissolution of magnesium substrate during the electroless plating process. In addition, SEM observation indicated that the corrosion inhibition reaction and the Ni2+ replacement reaction were competitive at the initial deposition time. Both electrochemical analysis and thermal shock test revealed that the Ni-P coating exhibited excellent corrosion resistance and adhesion properties in protecting the magnesium alloy.

  15. Prolonged high-dose intravenous magnesium therapy for severe tetanus in the intensive care unit: a case series

    PubMed Central

    2010-01-01

    Introduction Tetanus rarely occurs in developed countries, but it can result in fatal complications including respiratory failure due to generalized muscle spasms. Magnesium infusion has been used to treat spasticity in tetanus, and its effectiveness is supported by several case reports and a recent randomized controlled trial. Case presentations Three Caucasian Greek men aged 30, 50 and 77 years old were diagnosed with tetanus and admitted to a general 12-bed intensive care unit in 2006 and 2007 for respiratory failure due to generalized spasticity. Intensive care unit treatment included antibiotics, hydration, enteral nutrition, early tracheostomy and mechanical ventilation. Intravenous magnesium therapy controlled spasticity without the need for additional muscle relaxants. Their medications were continued for up to 26 days, and adjusted as needed to control spasticity. Plasma magnesium levels, which were measured twice a day, remained in the 3 to 4.5 mmol/L range. We did not observe hemodynamic instability, arrhythmias or other complications related to magnesium therapy in these patients. All patients improved, came off mechanical ventilation, and were discharged from the intensive care unit in a stable condition. Conclusion In comparison with previous reports, our case series contributes the following meaningful additional information: intravenous magnesium therapy was used on patients already requiring mechanical ventilation and remained effective for up to 26 days (significantly longer than in previous reports) without significant toxicity in two patients. The overall outcome was good in all our patients. However, the optimal dose, optimal duration and maximum safe duration of intravenous magnesium therapy are unknown. Therefore, until more data on the safety and efficacy of magnesium therapy are available, its use should be limited to carefully selected tetanus cases. PMID:20356376

  16. Electrophysiologic effects of intravenous magnesium in patients with normal conduction systems and no clinical evidence of significant cardiac disease.

    PubMed

    Kulick, D L; Hong, R; Ryzen, E; Rude, R K; Rubin, J N; Elkayam, U; Rahimtoola, S H; Bhandari, A K

    1988-02-01

    Parenteral magnesium has been used for several decades in the empiric treatment of various arrhythmias, but the data on its electrophysiologic effects in man are limited. We evaluated the electrophysiologic effects of magnesium sulfate (MgSO4) administration in eight normomagnesemic patients with normal mononuclear cell magnesium content, who had no clinically significant heart disease and had normal baseline electrophysiologic properties. After administration of intravenous MgSO4, serum magnesium rose significantly from 1.9 +/- 0.1 to 4.4 +/- 1.7 mg/dl (p less than 0.02). During a maintenance magnesium infusion, we observed significant prolongation of the ECG PR interval (145 +/- 18 to 155 +/- 26 msec, p less than 0.05), AH interval (77 +/- 27 to 83 +/- 26 msec, p less than 0.002), antegrade atrioventricular (AV) nodal effective refractory period (278 +/- 67 to 293 +/- 67 msec, p less than 0.05), and sinoatrial conduction time (60 +/- 34 to 76 +/- 32 msec, p less than 0.02). No significant effect was observed on sinus cycle length, sinus node recovery time, intra-atrial or intraventricular conduction times, QRS duration (during both sinus rhythm and ventricular pacing), QT interval, HV interval, paced cycle length resulting in AV nodal Wenckebach block, AV nodal functional refractory period, retrograde ventriculoatrial (VA) effective refractory period, or atrial and ventricular refractory periods. These findings, in conjunction with the demonstrated ability of magnesium to block slow channels for sodium movement, may provide an explanation of the mechanism by which magnesium exerts its effect in the treatment of atrial and junctional arrhythmias.

  17. Associations of dietary magnesium intake with mortality from cardiovascular disease: the JACC study.

    PubMed

    Zhang, Wen; Iso, Hiroyasu; Ohira, Tetsuya; Date, Chigusa; Tamakoshi, Akiko

    2012-04-01

    The authors sought to investigate the relationship between dietary magnesium intake and mortality from cardiovascular disease in a population-based sample of Asian adults. Reported findings are based on dietary magnesium intake in 58,615 healthy Japanese aged 40-79 years, in the Japan Collaborative Cohort (JACC) Study. Dietary magnesium intake was assessed by a validated food frequency questionnaire administered between 1988 and 1990. During the median 14.7-year follow-up, we documented 2690 deaths from cardiovascular disease, comprising 1227 deaths from strokes and 557 deaths from coronary heart disease. Dietary magnesium intake was inversely associated with mortality from hemorrhagic stroke in men and with mortality from total and ischemic strokes, coronary heart disease, heart failure and total cardiovascular disease in women. The multivariable hazard ratio (95% CI) for the highest vs. the lowest quintiles of magnesium intake after adjustment for cardiovascular risk factor and sodium intake was 0.49 (0.26-0.95), P for trend = 0.074 for hemorrhagic stroke in men, 0.68 (0.48-0.96), P for trend = 0.010 for total stroke, 0.47 (0.29-0.77), P for trend < 0.001 for ischemic stroke, 0.50 (0.30-0.84), P for trend = 0.005 for coronary heart disease, 0.50 (0.28-0.87), P for trend = 0.002 for heart failure and 0.64 (0.51-0.80), P for trend < 0.001 for total cardiovascular disease in women. The adjustment for calcium and potassium intakes attenuated these associations. In conclusion, dietary magnesium intake was associated with reduced mortality from cardiovascular disease in Japanese, especially for women.

  18. Pulmonary function of preeclamptic women receiving intravenous magnesium sulfate seizure prophylaxis.

    PubMed

    Herpolsheimer, A; Brady, K; Yancey, M K; Pandian, M; Duff, P

    1991-08-01

    Pulmonary function was studied in ten preeclamptic women in labor (mean gestational age 38.1 +/- 0.9 weeks measured from the last menstrual period) receiving continuous intravenous (IV) infusions of magnesium sulfate. Baseline maximal inspiratory pressure, maximal expiratory pressure, functional vital capacity, and forced expiratory volume at 1 second were measured immediately before a 6-g IV loading dose of magnesium sulfate and 2 hours after the initiation of a continuous 2-g/hour infusion of magnesium sulfate. Serum magnesium levels were measured at the same time pulmonary function tests were performed. All values are reported as the mean +/- standard deviation. The maximal inspiratory pressure, an indicator of generalized respiratory muscle weakness, decreased from a baseline value of 26.2 +/- 7.7 to 19.4 +/- 6.3 cm H2O (P less than .05). The maximal expiratory pressure, an indicator of expiratory muscle strength, decreased from a baseline value of 30.6 +/- 9.2 to 25.2 +/- 7.1 cm H2O (P less than .005). The functional vital capacity decreased from a baseline value of 3.37 +/- 0.49 to 3.19 +/- 0.73 L, and the forced expiratory volume at 1 second decreased from a baseline value of 2.61 +/- 0.58 to 2.36 +/- 0.68 L at 2 hours (P less than .05). The mean serum magnesium level was 1.7 +/- 0.2 mg/dL before the administration of the IV loading dose and 4.51 +/- 0.67 mg/dL 2 hours after initiation of the continuous infusion. Our results demonstrate a significant decrease in pulmonary function tests in term preeclamptic patients receiving magnesium sulfate for seizure prophylaxis.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Potassium and Magnesium Supplementation Do Not Protect Against Atrial Fibrillation After Cardiac Operation: A Time-Matched Analysis.

    PubMed

    Lancaster, Timothy S; Schill, Matthew R; Greenberg, Jason W; Moon, Marc R; Schuessler, Richard B; Damiano, Ralph J; Melby, Spencer J

    2016-10-01

    Despite a lack of demonstrated efficacy, potassium and magnesium supplementation are commonly thought to prevent postoperative atrial fibrillation (POAF) after cardiac operation. Our aim was to evaluate the natural time course of electrolyte level changes after cardiac operation and their relation to POAF occurrence. Data were reviewed from 2,041 adult patients without preoperative AF who underwent coronary artery bypass grafting, valve operation, or both between 2009 and 2013. In patients with POAF, the plasma potassium and magnesium levels nearest to the first AF onset time were compared with time-matched electrolyte levels in patients without AF. POAF occurred in 752 patients (36.8%). At the time of AF onset or the matched time point, patients with POAF had higher potassium (4.30 versus 4.21 mmol/L, p < 0.001) and magnesium (2.33 versus 2.16 mg/dL, p < 0.001) levels than controls. A stepwise increase in AF risk occurred with increasing potassium or magnesium quintile (p < 0.001). On multivariate logistic regression analysis, magnesium level was an independent predictor of POAF (odds ratio 4.26, p < 0.001), in addition to age, Caucasian race, preoperative β-blocker use, valve operation, and postoperative pneumonia. Prophylactic potassium supplementation did not reduce the POAF rate (37% versus 37%, p = 0.813), whereas magnesium supplementation was associated with increased POAF (47% versus 36%, p = 0.005). Higher serum potassium and magnesium levels were associated with increased risk of POAF after cardiac operation. Potassium supplementation was not protective against POAF, and magnesium supplementation was even associated with increased POAF risk. These findings help explain the poor efficacy of electrolyte supplementation in POAF prophylaxis. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  20. Low-temperature electron irradiation and annealing in pure magnesium

    SciTech Connect

    Simester, J.H.

    1982-01-01

    In this study of magnesium after 1.0 MeV electron irradiations at 1.55/sup 0/K, it has been observed that the damage production rate in Mg is (3.57 +- 0.03) x 10/sup -26/ ..cap omega..cm/(e/sup -/ cm/sup 2/). There is no evidence for thermal annealing up to 4/sup 0/K. The low temperature recovery in magnesium is found to consist of two broad substages between 4 to 14/sup 0/K, both of which exhibit evidence for correlated and uncorrelated recovery processes. The two substages are found to have very different frequency factors for annealing, and there is evidence that the recovery processes in the second substage are influenced by those in the first. A model for recovery is proposed using the split configuration in the plane which explains the first substage as being due to interstitial migration in the basal plane and the second to migration perpendicular to the plane.

  1. Magnesium incorporated bentonite clay for defluoridation of drinking water.

    PubMed

    Thakre, Dilip; Rayalu, Sadhana; Kawade, Raju; Meshram, Siddharth; Subrt, J; Labhsetwar, Nitin

    2010-08-15

    Low cost bentonite clay was chemically modified using magnesium chloride in order to enhance its fluoride removal capacity. The magnesium incorporated bentonite (MB) was characterized by using XRD and SEM techniques. Batch adsorption experiments were conducted to study and optimize various operational parameters such as adsorbent dose, contact time, pH, effect of co-ions and initial fluoride concentration. It was observed that the MB works effectively over wide range of pH and showed a maximum fluoride removal capacity of 2.26 mgg(-1) at an initial fluoride concentration of 5 mg L(-1), which is much better than the unmodified bentonite. The experimental data fitted well into Langmuir adsorption isotherm and follows pseudo-first-order kinetics. Thermodynamic study suggests that fluoride adsorption on MB is reasonably spontaneous and an endothermic process. MB showed significantly high fluoride removal in synthetic water as compared to field water. Desorption study of MB suggest that almost all the loaded fluoride was desorbed ( approximately 97%) using 1M NaOH solution however maximum fluoride removal decreases from 95.47 to 73 (%) after regeneration. From the experimental results, it may be inferred that chemical modification enhances the fluoride removal efficiency of bentonite and it works as an effective adsorbent for defluoridation of water.

  2. Fast kinetics of magnesium monochloride cations in interlayer-expanded titanium disulfide for magnesium rechargeable batteries

    DOE PAGES

    Yoo, Hyun Deog; Liang, Yanliang; Dong, Hui; ...

    2017-08-24

    Magnesium rechargeable batteries potentially offer high-energy density, safety, and low cost due to the ability to employ divalent, dendrite-free, and earth-abundant magnesium metal anode. Despite recent progress, further development remains stagnated mainly due to the sluggish scission of magnesium-chloride bond and slow diffusion of divalent magnesium cations in cathodes. Here in this paper we report a battery chemistry that utilizes magnesium monochloride cations in expanded titanium disulfide. Combined theoretical modeling, spectroscopic analysis, and electrochemical study reveal fast diffusion kinetics of magnesium monochloride cations without scission of magnesium-chloride bond. The battery demonstrates the reversible intercalation of 1 and 1.7 magnesium monochloridemore » cations per titanium at 25 and 60 °C, respectively, corresponding to up to 400 mAh g-1 capacity based on the mass of titanium disulfide. The large capacity accompanies with excellent rate and cycling performances even at room temperature, opening up possibilities for a variety of effective intercalation hosts for multivalent-ion batteries.« less

  3. Isotopically pure magnesium isotope-24 is prepared from magnesium-24 oxide

    NASA Technical Reports Server (NTRS)

    Chellew, N. R.; Schilb, J. D.; Steunenberg, R. K.

    1968-01-01

    Apparatus is used to prepare isotopically pure magnesium isotope-24, suitable for use in neutron scattering and polarization experiments. The apparatus permits thermal reduction of magnesium-24 oxide with aluminum and calcium oxide, and subsequent vaporization of the product metal in vacuum. It uses a resistance-heated furnace tube and cap assembly.

  4. An in vitro study on the biocompatibility of WE magnesium alloys.

    PubMed

    Ge, Shuping; Wang, Yi; Tian, Jie; Lei, Daoxi; Yu, Qingsong; Wang, Guixue

    2016-04-01

    Magnesium alloys are being actively studied for intravascular stent applications because of their good mechanical strength and biocompatibility. To rule out the high allergenicity of nickel and neurotoxicity of aluminum element, four kinds of WE magnesium alloys (where "W" represents the metallic element Y and "E" represents mixed rare earth (RE) elements; Y: 2.5, 5.0, 6.5, and 7.5 wt %; Nd: 1.0, 2.6, 2.5, and 4.2 wt %; Zr: 0.8 wt %) were chosen for in vitro investigation of their biocompatibility using cell culture. The results showed that, with the increase of rare earth elements in WE magnesium alloys, fibrinogen adsorption decreased and coagulation function was improved. It was also found that WE magnesium alloys promoted the adhesion of endothelial cells. With the increase of adhesion time, adhered cell numbers increased gradually. With 25% extracts, all the WE alloys promoted cell migration, while 100% extracts were not conducive to cell migration. Based on the above results, WE magnesium alloys 5.0WE (5.0Y-2.6Nd-0.8Zr) and 6.5WE (6.5Y-2.5Nd-0.8Zr) have better biocompatibility as compared with that with 2.5WE (2.5Y-1.0Nd-0.8Zr) and 7.5WE (7.5Y-4.2Nd-0.8Zr), and could be as the promising candidate materials for medical stent applications.

  5. Application of alkaline phosphatases from different sources in pharmaceutical and clinical analysis for the determination of their cofactors; zinc and magnesium ions.

    PubMed

    Muginova, Svetlana V; Zhavoronkova, Anna M; Polyakov, Alexei E; Shekhovtsova, Tatyana N

    2007-03-01

    Prospects of using different alkaline phosphatases bearing zinc and magnesium ions in their catalytic and allosteric sites, respectively, in pharmaceutical and clinical analysis were demonstrated. Also their application for the determination of zinc in insulin to control injection quality and magnesium in human urine for the diagnosis and treatment of magnesium deficiency was shown. The reaction of p-nitrophenyl phosphate hydrolysis was chosen as an indicator. The choice of appropriate alkaline phosphatase was substantiated, the influence of the nature of buffer solutions on the behavior of the enzyme-metal systems was studied, and the conditions of the indicator reaction proceeding in the presence of sample matrixes were optimized. Simple, rapid, sensitive, and selective enzymatic procedures for determining zinc and magnesium based on their inhibiting and activating effects on the catalytic activity of alkaline phosphatases from seal and chicken intestine, respectively, were developed.

  6. 40 CFR 461.60 - Applicability; description of the magnesium subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... magnesium subcategory. 461.60 Section 461.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Magnesium Subcategory § 461.60 Applicability; description of the magnesium subcategory. This subpart applies... treatment works from the manufacturing of magnesium anode batteries. ...

  7. 40 CFR 461.60 - Applicability; description of the magnesium subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... magnesium subcategory. 461.60 Section 461.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Magnesium Subcategory § 461.60 Applicability; description of the magnesium subcategory. This subpart applies... treatment works from the manufacturing of magnesium anode batteries. ...

  8. 40 CFR 461.60 - Applicability; description of the magnesium subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... magnesium subcategory. 461.60 Section 461.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Magnesium Subcategory § 461.60 Applicability; description of the magnesium subcategory. This subpart applies... treatment works from the manufacturing of magnesium anode batteries. ...

  9. The IMA Study on the Life Cycle Assessment (LCA) of Magnesium

    NASA Astrophysics Data System (ADS)

    Friedrich, Horst E.; Ehrenberger, Simone

    Magnesium shows considerable potentials as lightweight material for weight sensitive applications. To assess the potential environmental benefits of magnesium in transport applications, the International Magnesium Association (IMA) initiated a study on the life cycle assessment (LCA) of magnesium.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Hydrogen Adsorption onto Magnesium Palladium and Magnesium Palladium Niobium Multilayer Thin Films

    NASA Astrophysics Data System (ADS)

    Steinmetz, Christian; Hettinger, Jeffrey; Dobbins, Tabbetha

    2013-03-01

    We report on the synthesis and characterization of magnesium palladium and magnesium niobium multilayer thin films as a possible reversible hydrogen storage material. The multilayer thin films are characterized by x-ray diffraction (XRD) and x-ray reflectivity (XRR) before and after hydrogen uptake. This study examines the optimal thickness of the magnesium film which would allow the diffusion of hydrogen to form magnesium hydride (MgH2). Thin barriers of palladium and niobium permit hydrogen to permeate while acting as a diffusion barrier to oxygen. Multilayer thin films are grown with various magnesium thicknesses via magnetron sputtering on a sapphire substrate. Thicknesses of Mg, MgH2, Pd, and Nb are reported. Likewise, interfacial roughness attributable to hydrogenation and dehydrogenation cycling measured using XRR are reported.

  12. Iatrogenic magnesium toxicity following intravenous infusion of magnesium sulfate: risks and strategies for prevention.

    PubMed

    Cavell, Gillian F; Bryant, Catherine; Jheeta, Seetal

    2015-07-31

    A 65-year-old man being treated with radiotherapy and chemotherapy for recurrent colonic adenocarcinoma was admitted for management of hypokalaemia and hypomagnesaemia secondary to diarrhoea. He was treated with intravenous infusions of potassium chloride and magnesium sulfate. Following an infusion of magnesium sulfate, he experienced a sudden neurological deterioration. A CT of the head revealed no haemorrhage or evidence of acute ischaemic injury. Results of serum biochemistry later that day revealed an elevated magnesium level. Iatrogenic magnesium toxicity was suspected. Further discussions between the pharmacist and ward staff confirmed that a medication error had been made in the preparation of the infusion resulting in an overdose of intravenous magnesium. 2015 BMJ Publishing Group Ltd.

  13. Leaf Senescence by Magnesium Deficiency

    PubMed Central

    Tanoi, Keitaro; Kobayashi, Natsuko I.

    2015-01-01

    Magnesium ions (Mg2+) are the second most abundant cations in living plant cells, and they are involved in various functions, including photosynthesis, enzyme catalysis, and nucleic acid synthesis. Low availability of Mg2+ in an agricultural field leads to a decrease in yield, which follows the appearance of Mg-deficient symptoms such as chlorosis, necrotic spots on the leaves, and droop. During the last decade, a variety of physiological and molecular responses to Mg2+ deficiency that potentially link to leaf senescence have been recognized, allowing us to reconsider the mechanisms of Mg2+ deficiency. This review focuses on the current knowledge about the physiological responses to Mg2+ deficiency including a decline in transpiration, accumulation of sugars and starch in source leaves, change in redox states, increased oxidative stress, metabolite alterations, and a decline in photosynthetic activity. In addition, we refer to the molecular responses that are thought to be related to leaf senescence. With these current data, we give an overview of leaf senescence induced by Mg deficiency. PMID:27135350

  14. Grosnaja ABCs: Magnesium isotope compositions

    NASA Technical Reports Server (NTRS)

    Goswami, J. N.; Srinivasan, G.; Ulyanov, A. A.

    1993-01-01

    Three CAI's from the Grosnaja CV3 chondrite were analyzed for their magnesium isotopic compositions by the ion microprobe. The selected CAI's represent three distinct types: GR4(compact Type A), GR7(Type B) and GR2(Type C). Petrographic studies indicate that all three Grosnaja inclusions were subjected to secondary alterations. The Type A CAI GR4 is primarily composed of melilite with spinel and pyroxene occurring as minor phases. The rim of the inclusion does not exhibit distinct layered structure and secondary alteration products (garnet, Fe-rich olivine and Na-rich plagioclase) are present in some localized areas near the rim region. The average major element compositions of different mineral phases in GR4 are given. Preliminary REE data suggest a depletion of HREE relative to LREE by about a factor of 3 without any clear indication of interelement fractionation. The CAI GR7 has textural and minerological characteristics similar to Type B inclusions. The REE data show a pattern that is similar to Group 6 with enrichment in Eu and Yb. In addition, a depletion of HREE compared to LREE is also evident in this object. Melilite composition shows a broad range of akermanite content (Ak(sub 15-55)). Detailed petrographic study is in progress. GR2 is a anorthite-rich Type C inclusion with large plagioclase laths intergrown with Ti-rich pyroxene. The average plagioclase composition is close to pure anorthite (An99).

  15. Serum Magnesium Status in Patients Subjects with Depression in the City of Yazd in Iran 2013-2014.

    PubMed

    Rajizadeh, Afsaneh; Mozaffari-Khosravi, Hassan; Yassini-Ardakani, Mojtaba; Dehghani, Ali

    2016-06-01

    Depression is the most common mental disorder and involves many factors. The regulatory effects of magnesium on N-methyl-D-aspartate (NMDA) channels make it a factor in the treatment of depression. The present study investigated the level of serum magnesium in subjects diagnosed with depression in the city of Yazd in Iran. This cross-sectional study was done from January 2013 to January 2014 on 650 patients with depression who agreed to participate in this study. Diagnosis was made using the Beck Depression Inventory test (BDI-II); those scoring higher than 11 were sent to the medical school laboratory for further testing of serum magnesium levels. The mean age of the patients was 34.16 ± 9.12 years. Of the 650 subjects, 195 were male (30 %) and 455 were female (70 %). The total mean serum magnesium was 2.1 ± 0.26 mg/dl. The prevalence of hypomagnesemia 13.7 %, hypermagnesemia 8.3 %, and sub-optimal magnesium levels was 26.5 %. Sub-optimal prevalence in women (28.1 %) was higher than in men (26.2 %). A significant relationship was observed between depression and serum magnesium level (p = 0.02). The results indicated that the prevalence of hypomagnesemia in subjects diagnosed with depression is high compared to non-depressed individuals. Moreover, there was a significant relationship between hypomagnesemia and intensity of depression that suggests a role for this element in the pathogenesis of the disorder. The high sub-optimal prevalence among women indicates that increased attention should be paid to this group.

  16. Phase composition, mechanical performance and in vitro biocompatibility of hydraulic setting calcium magnesium phosphate cement.

    PubMed

    Klammert, Uwe; Reuther, Tobias; Blank, Melanie; Reske, Isabelle; Barralet, Jake E; Grover, Liam M; Kübler, Alexander C; Gbureck, Uwe

    2010-04-01

    Brushite (CaHPO(4) x 2H(2)O)-forming calcium phosphate cements are of great interest as bone replacement materials because they are resorbable in physiological conditions. However, their short setting times and low mechanical strengths limit broad clinical application. In this study, we showed that a significant improvement of these properties of brushite cement could be achieved by the use of magnesium-substituted beta-tricalcium phosphate with the general formula Mg(x)Ca((3-x))((PO(4))(2) with 0 < x < 3 as cement reactants. The incorporation of magnesium ions increased the setting times of cements from 2 min for a magnesium-free matrix to 8-11 min for Mg(2.25)Ca(0.75)(PO(4))(2) as reactant. At the same time, the compressive strength of set cements was doubled from 19 MPa to more than 40 MPa after 24h wet storage. Magnesium ions were not only retarding the setting reaction to brushite but were also forming newberyite (MgHPO(4) x 3H(2)O) as a second setting product. The biocompatibility of the material was investigated in vitro using the osteoblast-like cell line MC3T3-E1. A considerable increase of cell proliferation and expression of alkaline phosphatase, indicating an osteoblastic differentiation, could be noticed. Scanning electron microscopy analysis revealed an obvious cell growth on the surface of the scaffolds. Analysis of the culture medium showed minor alterations of pH value within the physiological range. The concentrations of free calcium, magnesium and phosphate ions were altered markedly due to the chemical solubility of the scaffolds. We conclude that the calcium magnesium phosphate (newberyite) cements have a promising potential for their use as bone replacement material since they provide a suitable biocompatibility, an extended workability and improved mechanical performance compared with brushite cements.

  17. The effect of magnesium on early osseointegration in osteoporotic bone: a histological and gene expression investigation.

    PubMed

    Galli, S; Stocchero, M; Andersson, M; Karlsson, J; He, W; Lilin, T; Wennerberg, A; Jimbo, R

    2017-07-01

    Magnesium has a key role in osteoporosis and could enhance implant osseointegration in osteoporotic patients. Titanium implants impregnated with Mg ions were installed in the tibia of ovariectomized rats. The release of Mg induced a significant increase of bone formation and the expression of anabolic markers in the peri-implant bone. The success of endosseous implants is highly predictable in patients possessing normal bone status, but it may be impaired in patients with osteoporosis. Thus, the application of strategies that adjuvate implant healing in compromized sites is of great interest. Magnesium has a key role in osteoporosis prevention and it is an interesting candidate for this purpose. In this study, the cellular and molecular effects of magnesium release from implants were investigated at the early healing stages of implant integration. Osteoporosis was induced in 24 female rats by means of ovariectomy and low-calcium diet. Titanium mini-screws were coated with mesoporous titania films and were loaded with magnesium (test group) or left as native (control group). The implants were inserted in the tibia and femur of the rats. One, 2 and 7 days after implantation, the implants were retrieved and histologically examined. In addition, expression of genes was evaluated in the peri-implant bone tissue at day 7 by means of quantitative polymerase chain reactions with pathway-oriented arrays. The histological evaluation revealed that new bone formation started already during the first week of healing for both groups. However, around the test implants, new bone was significantly more abundant and spread along a larger surface of the implants. In addition, the release of magnesium induced a significantly higher expression of BMP6. These results provide evidence that the release of magnesium promoted rapid bone formation and the activation of osteogenic signals in the vicinity of implants placed in osteoporotic bone.

  18. Synthesis and optical study of barium magnesium aluminate blue phosphors

    SciTech Connect

    Jeet, Suninder Pandey, O. P.; Sharma, Manoj

    2015-05-15

    Europium doped barium magnesium aluminate (BaMgAl{sub 10}O{sub 17}:Eu{sup 2+}) phosphor was prepared via solution combustion method at 550°C using urea as a fuel. Morphological and optical properties of the prepared sample was studied by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Photoluminescence spectroscopy (PL). XRD result showed the formation of pure phase BaMgAl{sub 10}O{sub 17}(JCPDS 26-0163) along with an additional phase BaAl{sub 2}O{sub 4}(JCPDS 01-082-1350). TEM image indicated the formation of faceted particles with average particle size 40 nm. From PL spectra, a broad emission band obtained at about 450 nm attributes to 4f{sup 6} 5d → 4f{sup 7} transition of Eu{sup 2+} which lies in the blue region of the visible spectrum.

  19. Synthesis and optical study of barium magnesium aluminate blue phosphors

    NASA Astrophysics Data System (ADS)

    Jeet, Suninder; Sharma, Manoj; Pandey, O. P.

    2015-05-01

    Europium doped barium magnesium aluminate (BaMgAl10O17:Eu2+) phosphor was prepared via solution combustion method at 550°C using urea as a fuel. Morphological and optical properties of the prepared sample was studied by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Photoluminescence spectroscopy (PL). XRD result showed the formation of pure phase BaMgAl10O17(JCPDS 26-0163) along with an additional phase BaAl2O4(JCPDS 01-082-1350). TEM image indicated the formation of faceted particles with average particle size 40 nm. From PL spectra, a broad emission band obtained at about 450 nm attributes to 4f6 5d → 4f7 transition of Eu2+ which lies in the blue region of the visible spectrum.

  20. Effect of acute hyperinsulinemia on magnesium homeostasis in humans.

    PubMed

    Xu, Li Hao Richie; Maalouf, Naim M

    2017-02-01

    Insulin may influence magnesium homeostasis through multiple mechanisms. Acutely, it stimulates the shift of magnesium from plasma into red blood cells and platelets, and in vitro, it stimulates the activity of the TRPM6 channel, a key regulator of renal magnesium reabsorption. We investigated the impact of hyperinsulinemia on magnesium handling in participants with a wide range of insulin sensitivity. Forty-seven participants were recruited, including 34 nondiabetic controls and 13 with type 2 diabetes mellitus. After stabilization under fixed metabolic diet, participants underwent hyperinsulinemic-euglycemic clamp. Serum and urine samples were collected before and during hyperinsulinemia. Change in serum magnesium, urinary magnesium to creatinine (Mg(2)(+) :Cr) ratio, fractional excretion of urinary magnesium (FEMg(2)(+) ), and estimated transcellular shift of magnesium were compared before and during hyperinsulinemia. Hyperinsulinemia led to a small but statistically significant decrease in serum magnesium, and to a shift of magnesium into the intracellular compartment. Hyperinsulinemia did not significantly alter urinary magnesium to creatinine ratio or fractional excretion of urinary magnesium in the overall population, although a small but statistically significant decline in these parameters occurred in participants with diabetes. There was no significant correlation between change in fractional excretion of urinary magnesium and body mass index or insulin sensitivity measured as glucose disposal rate. In human participants, acute hyperinsulinemia stimulates the shift of magnesium into cells with minimal alteration in renal magnesium reabsorption, except in diabetic patients who experienced a small decline in fractional excretion of urinary magnesium. The magnitude of magnesium shift into the intracellular compartment in response to insulin does not correlate with that of insulin-stimulated glucose entry into cells. Copyright © 2016 John Wiley & Sons, Ltd.