WorldWideScience

Sample records for investigating magnesium dependence

  1. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    Directory of Open Access Journals (Sweden)

    Berat Barıs BULDUM

    2013-01-01

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

  2. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    OpenAIRE

    Berat Barıs BULDUM; Aydın SIK; Iskender OZKUL

    2013-01-01

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

  3. Electrochemical investigations related to solid state magnesium ...

    Indian Academy of Sciences (India)

    Administrator

    Investigations leading to the understanding and development of solid state magnesium batteries are considered important, as Mg is free from hazards and is also highly stable and abundant. A gel polymer electrolyte (GPE) of about 100 mm thickness is investigated for electrochemical reversibility of the Mg/Mg2+ couple and ...

  4. Investigation of samarium solubility in the magnesium based solid solution

    International Nuclear Information System (INIS)

    Rokhlin, L.L.; Padezhnova, E.M.; Guzej, L.S.

    1976-01-01

    Electric resistance measurements and microscopic analysis were used to investigate the solubility of samarium in a magnesium-based solid solution. The constitutional diagram Mg-Sm on the magnesium side is of an eutectic type with the temperature of the eutectic transformation of 542 deg C. Samarium is partly soluble in solid magnesium, the less so, the lower is the temperature. The maximum solubility of samarium in magnesium (at the eutectic transformation point) is 5.8 % by mass (0.99 at. %). At 200 deg C, the solubility of samarium in magnesium is 0.4 % by mass (0.063 at. %)

  5. Magnesium

    Science.gov (United States)

    ... Consumer Datos en español Health Professional Other Resources Magnesium Fact Sheet for Consumers Have a question? Ask ... find out more about magnesium? Disclaimer What is magnesium and what does it do? Magnesium is a ...

  6. Ionized magnesium in plasma and erythrocytes for the assessment of low magnesium status in alcohol dependent patients.

    Science.gov (United States)

    Ordak, Michal; Maj-Zurawska, Magdalena; Matsumoto, Halina; Bujalska-Zadrozny, Magdalena; Kieres-Salomonski, Ilona; Nasierowski, Tadeusz; Muszynska, Elzbieta; Wojnar, Marcin

    2017-09-01

    Studies on the homeostasis of magnesium in alcohol-dependent patients have often been characterized by low hypomagnesemia detection rates. This may be due to the fact that the content of magnesium in blood serum constitutes only 1% of the average magnesium level within the human body. However, the concentration of ionized magnesium is more physiologically important and makes up 67% of the total magnesium within a human organism. There are no data concerning the determination of the ionized fraction of magnesium in patients addicted to alcohol and its influence on mental health status. This study included 100 alcohol-dependent patients and 50 healthy subjects. The free magnesium fraction was determined using the potentiometric method by means of using ion-selective electrodes. The total magnesium level was determined by using a biochemical Indiko Plus analyzer. In this study, different psychometric scales were applied. Our results confirm the usefulness of ionized magnesium concentrations in erythrocytes and plasma as a diagnostic parameter of low magnesium status in alcohol-dependent patients. The lower the concentration of ionized magnesium, the worse the quality of life an alcohol-dependent person might experience. In the case of total magnesium, no such correlation was determined. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Interactions between bicarbonate, potassium, and magnesium, and sulfur-dependent induction of luminescence in Vibrio fischeri.

    Science.gov (United States)

    Tabei, Yosuke; Era, Mariko; Ogawa, Akane; Morita, Hiroshi

    2012-06-01

    In spite of its central importance in research efforts, the relationship between seawater compounds and bacterial luminescence has not previously been investigated in detail. Thus, in this study, we investigated the effect of cations (Na(+) , K(+) , NH(4) (+) , Mg(2+) , and Ca(2+) ) and anions (Cl(-) , HCO(3) (-) , CO(3) (2-) , and NO(3) (-) ) on the induction of both inorganic (sulfate, sulfite, and thiosulfate) and organic (L-cysteine and L-cystine) sulfur-dependent luminescence in Vibrio fischeri. We found that HCO(3) (-) (bicarbonate) and CO(3) (2-) (carbonate), in the form of various compounds, had a stimulatory effect on sulfur-dependent luminescence. The luminescence induced by bicarbonate was further promoted by the addition of magnesium. Potassium also increased sulfur-dependent luminescence when sulfate or thiosulfate was supplied as the sole sulfur source, but not when sulfite, L-cysteine, or L-cystine was supplied. The positive effect of potassium was accelerated by the addition of magnesium and/or calcium. Furthermore, the additional supply of magnesium improved the induction of sulfite- or L-cysteine-dependent luminescence, but not the l-cystine-dependent type. These results suggest that sulfur-dependent luminescence of V. fischeri under nutrient-starved conditions is mainly controlled by bicarbonate, carbonate, and potassium. In addition, our results indicate that an additional supply of magnesium is effective for increasing V. fischeri luminescence. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Magnesium chloride concentration-dependent formation of tofu-like precipitates with different physicochemical properties.

    Science.gov (United States)

    Arii, Yasuhiro; Takenaka, Yasuyuki

    2013-01-01

    A wet precipitate is generated in the process of making tofu by adding a coagulant to the basic soymilk ingredient. We investigated the magnesium chloride concentration-dependent change in the precipitate weight. The wet precipitate weight dramatically increased following a short plateau phase at a low concentration of magnesium chloride. It is interesting that this weight slightly decreased following a long plateau phase at a high concentration. These low and high concentrations respectively induced precipitates with a smooth surface and rough surface. The precipitate with a smooth surface had a higher water content than that with a rough surface. These precipitates also had obviously different solubility in various chemical reagents. The different properties indicate that these precipitates were formed by different intermolecular interactions. These results can be utilized to more clearly understand the mechanisms involved in tofu formation.

  9. Effects of ketamine and magnesium on morphine induced tolerance and dependence in mice

    Directory of Open Access Journals (Sweden)

    Bohlul Habibi Asl

    2005-05-01

    Full Text Available The goal of this study was to evaluate the effects of ketamine and magnesium on prevention of development of morphine tolerance and dependence in mice. In this study different groups of mice received morphine (50 mg/kg, sc + (saline 10ml/kg, morphine (50 mg/kg, sc + ketamine (25,50 or 75mg/kg, ip, morphine (50 mg/kg, sc + magnesium (10,20 or 40 mg/kg, ip, morphine (50 mg/kg, sc +ketamine (25 mg/kg, ip + magnesium (10 mg/kg, ip] once a day for four days. Tolerance was assessed by administration of morphine (9 mg/kg, ip and using hot plate test on fifth day. Withdrawal symptoms were assessed by administration of naloxone (4 mg/kg, ip two hours after co-administration of morphine with either ketamine or magnesium. It was found that pretreatment with ketamine or magnesium decreased the degree of tolerance and dependence. Additionally, co-administration of ketamine and magnesium before morphine administration decreased the tolerance and dependence significantly. From these results it may be concluded that administration of ketamine or magnesium alone or together could prevent the development of tolerance and dependence to the analgesic effects of morphine. These effects may be related to the N-Methyl-DAspartate (NMDA receptor antagonist behavior of ketamine and the ability of magnesium to block the Ca channel of NMDA receptors.

  10. Ion beam investigation of hydrogen implanted in magnesium

    International Nuclear Information System (INIS)

    Chami, A.-C.

    1977-01-01

    The diffusion mechanism for hydrogen implanted in magnesium was investigated by nuclear reaction analysis or channeling. The hydrogen introduced is then in the presence of radiation defects created by implantation. The H( 11 B,α) reaction used allowed the profiles of implanted hydrogen to be drawn. The Winterbon calculations derived from LSS theory (Lindhard, Scharff, Schiott) were used. LSS profiles folding and the excitation curve unfolding give very same results. An analysis of the profile of the defects and the evaluation of the total number of Frenkel pairs produced show that the defects are isolated when low energy light elements are implanted, and hydrogen interactions are effected through point defects. A channeling analysis shows that hydrogen occupies tetrahedral sites as far as the temperature remains lower that the migration temperature (about 100K). Beyonds this temperature, the hydrogen migrates and is trapped on motionless defects [fr

  11. Magnesium

    Science.gov (United States)

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

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

  12. Temperature dependence of twinning activity in random textured cast magnesium

    Czech Academy of Sciences Publication Activity Database

    Čapek, J.; Farkas, G.; Pilch, Jan; Máthis, K.

    2015-01-01

    Roč. 627, MAR (2015), s. 333-335 ISSN 0921-5093 R&D Projects: GA ČR(CZ) GAP204/12/1360; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : magnesium * acoustic emission * neutron diffraction * deformation twinning * high temperature Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.647, year: 2015

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

    Science.gov (United States)

    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

  14. Magnesium Oxide

    Science.gov (United States)

    Magnesium is an element your body needs to function normally. Magnesium oxide may be used for different reasons. Some people use it as ... one to four times daily depending on which brand is used and what condition you have. Follow ...

  15. The Temperature Dependence of the Debye-Waller Factor of Magnesium

    DEFF Research Database (Denmark)

    Sledziewska-Blocka, D.; Lebech, Bente

    1976-01-01

    The temperature dependence of the average Debye-Waller factor for magnesium was measured by means of neutron diffraction spectrometry. The experimental results obtained in the temperature range from 5 to 256 K are compared with theoretical calculations, using the harmonic and quasi-harmonic appro......The temperature dependence of the average Debye-Waller factor for magnesium was measured by means of neutron diffraction spectrometry. The experimental results obtained in the temperature range from 5 to 256 K are compared with theoretical calculations, using the harmonic and quasi...

  16. Time-dependent physicochemical characteristics of Malaysian residual soil stabilized with magnesium chloride solution

    OpenAIRE

    Latifi, Nima; Rashid, Ahmad Safuan A.; Ecemiş, Nurhan; Tahir, Mahmood Md; Marto, Aminaton

    2016-01-01

    The effects of non-traditional additives on the geotechnical properties of tropical soils have been the subject of investigation in recent years. This study investigates the strength development and micro-structural characteristics of tropical residual soil stabilized with magnesium chloride (MgCl2) solution. Unconfined compression strength (UCS) and standard direct shear tests were used to assess the strength and shear properties of the stabilized soil. In addition, the micro-structural char...

  17. Investigation of biodegradable ternary Mg-Zn-La magnesium alloys

    Science.gov (United States)

    Özarslan, Selma; Şevik, Hüseyin; Sorar, Idris

    2018-02-01

    In this paper, the effect of Lanthanum (1, 2 and 4 wt.%) addition to biodegradable Mg-4Zn alloy and its influence on the microstructure and mechanical properties of the alloy were investigated. The alloys were produced under protective atmosphere by a cold chamber high pressure-die casting process. Microstructure analysis of the samples were carried out by scanning electron microscopy (SEM), an energy-dispersive spectrometer (EDS) and X-ray diffraction (XRD). X-ray difractometry revealed that the main phases are α-Mg and MgZn in the whole alloys. Also, the Mg17La2 phase was observed with addition of La. Hardness and tensile properties were examined to investigate the mechanical properties. Results showed that the yield strength and nanohardness of main alloy were improved from 40 % (100 MPa to 140 MPa), 24 % (from 1.04 GPa to 1.29 GPa) with addition of 4 wt.% La, respectively. However, elongation was decreased with increasing of La content.

  18. Orientation dependent slip and twinning during compression and tension of strongly textured magnesium AZ31 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Al-Samman, T., E-mail: al-samman@imm.rwth-aachen.de [Institut fuer Metallkunde und Metallphysik, RWTH Aachen, Kopernikusstr. 14, D-52064 Aachen (Germany); Li, X. [Institut fuer Metallkunde und Metallphysik, RWTH Aachen, Kopernikusstr. 14, D-52064 Aachen (Germany); Chowdhury, S. Ghosh [CSIR National Metallurgical Laboratory, MST Division, Jamshedpur 831007 (India)

    2010-06-15

    Over recent years there have been a remarkable number of studies dealing with compression of magnesium. A literature search, however, shows a noticeably less number of papers concerned with tension and a very few papers comparing both modes, systematically, in one study. The current investigation reports the anisotropic deformation behavior and concomitant texture and microstructure evolution investigated in uniaxial tension and compression tests in two sample directions performed on an extruded commercial magnesium alloy AZ31 at different Z conditions. For specimens with the loading direction parallel to the extrusion axis, the tension-compression strength anisotropy was pronounced at high Z conditions. Loading at 45{sup o} from the extrusion axis yielded a tension-compression strength behavior that was close to isotropic. During tensile loading along the extrusion direction the extrusion texture resists twinning and favors prismatic slip (contrary to compression). This renders the shape change maximum in the basal plane and equal to zero along the c-axis, which resulted in the orientation of individual grains remaining virtually intact during all tension tests at different Z conditions. For the other investigated sample direction, straining was accommodated along the c-axis, which was associated with a lattice rotation, and thus, a change of crystal orientation. Uniaxial compression at a low Z condition (400 deg. C/10{sup -4} s{sup -1}) yielded a desired texture degeneration, which was explained on the basis of a more homogeneous partitioning of slip systems that reduces anisotropy and enhanced dynamic recrystallization (DRX), which counteracts the strong deformation texture. The critical strains for the nucleation of DRX in tensiled specimens at the highest investigated Z condition (200 deg. C/10{sup -2} s{sup -1}) were found to range between 4% and 5.6%.

  19. Exoelectron emission from magnesium borate glass ceramics

    International Nuclear Information System (INIS)

    Kawamoto, Takamichi; Yanagisawa, Hideo; Nakamichi, Hiroshi; Kikuchi, Riichi; Kawanishi, Masaharu.

    1986-01-01

    Thermally stimulated exoelectron emission (TSEE) of a magnesium borate glass ceramics was investigated for its application to dosemetric use. It has been found that the TSEE glow patterns of the magnesium borate glass ceramics as well as a Li 2 B 4 O 7 glass ceramics depend on the kind of the radiation used and that the heat resistance of the magnesium borate glass ceramics is higher than that of the Li 2 B 4 O 7 glass ceramics. Therefore, the TSEE glow patterns of the magnesium borate glass ceramics indicate a possibility to be used as the dose measurement for each kind of radiation in the mixed radiation field. (author)

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

    NARCIS (Netherlands)

    Flores Ramirez, J.R.

    2006-01-01

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

  1. Investigations of effects of magnesium, zinc and copper on cadmium excretion in rabbits

    Directory of Open Access Journals (Sweden)

    Bulat Zorica

    2012-01-01

    Full Text Available Cadmium (Cd is today one of the most significant metal poisons, both in the area of professional as well as of eco toxicology. In the organism, cadmium has a harmful effect on the kidneys, liver, bones, testicles, etc., and, based on evidence in humans that it causes lung carcinoma, it has been placed in the first group of carcinogens. In spite of numerous data in literature on the harmful effects of cadmium, the interactions between cadmium and bioelements as a significant mechanism for cadmium toxicity have still not been sufficiently explained. Since the data so far point to a positive effect of supplementation with certain bioelements regarding toxicity and cadmium content in the organism, the objective of this work was to investigate the effect of increased simultaneous intake of magnesium, zinc and copper on urinary elimination of cadmium in rabbits exposed to cadmium. Rabbits were divided into two groups: Cd group - for a period of 28 days the animals received per os 10 mg Cd/kg b.m/day and Cd+(Mg+Zn+Cu group - 10 mg Cd/kg b.m. + 40 mg Mg/kg b.m, 20 mg Zn/kg b.m. and 10 mg Cu/kg b.m/day. Daily urine was collected on days 0, 10, 15, 17, 19, 21, 23, 25, and 28 of the experiment. Following decomposition of urine samples with the help of concentrated HNO3 and HClO4 (4:1, the metal concentration was determined using the method of atomic absorption spectrophotometry. Supplementation with magnesium, zinc and copper did not result in significant changes in the elimination of cadmium through urine in animals poisoned with cadmium, in comparison with the animals that were administered only cadmium, while the concentration of all three applied bioelements in urine was significantly increased. It can be concluded that the simultaneous administration of increased doses of zinc, copper and magnesium does not have a positive effect on the elimination of cadmium in conditions when rabbits are poisoned with cadmium.

  2. Magnesium Gluconate

    Science.gov (United States)

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

  3. Dependence of twinned volume fraction on loading mode and Schmid factor in randomly textured magnesium

    Czech Academy of Sciences Publication Activity Database

    Čapek, Jan; Máthis, K.; Clausen, B.; Barnett, M.R.

    2017-01-01

    Roč. 130, MAY (2017), s. 319-328 ISSN 1359-6454 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61389005 Keywords : twinning * magnesium * neutron diffraction * Schmid factor Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 5.301, year: 2016

  4. Nutrition and magnesium absorption

    OpenAIRE

    Brink, E.J.

    1992-01-01

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

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

    Czech Academy of Sciences Publication Activity Database

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

    2012-01-01

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

  6. Investigation Of Temperature Dependent Characteristics Of ...

    African Journals Online (AJOL)

    The structure, magnetization and magnetostriction of Laves phase compound TbCo2 were investigated by temperature dependent high resolution neutron powder diffraction. The compound crystallizes in the cubic Laves phase C15 structure above its Curie temperature, TC and exhibits a rhombohedral distortion (space ...

  7. Time-dependent electrochemical characterization of the corrosion of a magnesium rare-earth alloy in simulated body fluids.

    Science.gov (United States)

    Rettig, Ralf; Virtanen, Sannakaisa

    2008-04-01

    The electrochemistry of the corrosion process of a magnesium rare-earth-alloy is studied in detail in simulated body fluid (m-SBF) over the first 5 days. The aim is to investigate the corrosion mechanism under in vitro conditions. For this purpose we also used electrolytes that contain only some of the components of SBF, they were compared to SBF to investigate the influence of the different ions in SBF. The influence of albumin on the corrosion process was studied with a solution containing m-SBF and albumin in physiological concentration. For this study, impedance spectroscopy series measurements were performed. Additional results were gained from polarization curves. We conclude from the study that the corrosion resistance is significantly lower in m-SBF than in simple isotonic NaCl-solution. Albumin may form a blocking layer on the surface in the first hours of exposure. The formed corrosion layers consisting of amorphous apatite have only a low protective ability. Further results show that the corrosion processes in SBFs follow a linear time-law. The results elucidate critical factors and mechanisms of the electrochemical corrosion process of magnesium rare-earth alloys in SBFs, this understanding is crucial for a successful application of Mg alloys in biomedical applications. Copyright 2007 Wiley Periodicals, Inc.

  8. Investigations of Low Temperature Time Dependent Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Van der Sluys, W A; Robitz, E S; Young, B A; Bloom, J

    2002-09-30

    The objective of this project was to investigate metallurgical and mechanical phenomena associated with time dependent cracking of cold bent carbon steel piping at temperatures between 327 C and 360 C. Boiler piping failures have demonstrated that understanding the fundamental metallurgical and mechanical parameters controlling these failures is insufficient to eliminate it from the field. The results of the project consisted of the development of a testing methodology to reproduce low temperature time dependent cracking in laboratory specimens. This methodology was used to evaluate the cracking resistance of candidate heats in order to identify the factors that enhance cracking sensitivity. The resultant data was integrated into current available life prediction tools.

  9. Magnesium and Osteoporosis

    Directory of Open Access Journals (Sweden)

    Ferda Özdemir

    2004-03-01

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

  10. Investigation of Stress Corrosion Cracking in Magnesium Alloys by Quantitative Fractography Methods

    Directory of Open Access Journals (Sweden)

    Sozańska M.

    2017-06-01

    Full Text Available The article shows that the use of quantitative fracture description may lead to significant progress in research on the phenomenon of stress corrosion cracking of the WE43 magnesium alloy. Tests were carried out on samples in air, and after hydrogenation in 0.1 M Na2SO4 with cathodic polarization. Fracture surfaces were analyzed after different variants of the Slow Strain Rate Test. It was demonstrated that the parameters for quantitative evaluation of fracture surface microcracks can be closely linked with the susceptibility of the WE43 magnesium alloy operating under complex state of the mechanical load in corrosive environments. The final result of the study was the determination of the quantitative relationship between Slow Strain Rate Test parameters, the mechanical properties, and the parameters of the quantitative evaluation of fracture surface (microcracks.

  11. Structure and Properties Investigation of MCMgAl12Zn1 Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Dobrzański L.A.

    2013-03-01

    Full Text Available This work presents an influence of cooling rate on crystallization process, structure and mechanical properties of MCMgAl12Zn1 cast magnesium alloy. The experiments were performed using the novel Universal Metallurgical Simulator and Analyzer Platform. The apparatus enabled recording the temperature during refrigerate magnesium alloy with three different cooling rates, i.e. 0.6, 1.2 and 2.4°C/s and calculate a first derivative. Based on first derivative results, nucleation temperature, beginning of nucleation of eutectic and solidus temperature were described. It was fund that the formation temperatures of various thermal parameters, mechanical properties (hardness and ultimate compressive strength and grain size are shifting with an increasing cooling rate.

  12. Investigations of a two-level atom in a magneto-optical trap using magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Loo, F Y [Niels Bohr Institute, Oersted Laboratory, Universitetsparken 5, DK-2100 Copenhagen (Denmark); Brusch, A [Niels Bohr Institute, Oersted Laboratory, Universitetsparken 5, DK-2100 Copenhagen (Denmark); Sauge, S [Niels Bohr Institute, Oersted Laboratory, Universitetsparken 5, DK-2100 Copenhagen (Denmark); Allegrini, M [Niels Bohr Institute, Oersted Laboratory, Universitetsparken 5, DK-2100 Copenhagen (Denmark); Arimondo, E [Niels Bohr Institute, Oersted Laboratory, Universitetsparken 5, DK-2100 Copenhagen (Denmark); Andersen, N [Niels Bohr Institute, Oersted Laboratory, Universitetsparken 5, DK-2100 Copenhagen (Denmark); Thomsen, J W [Niels Bohr Institute, Oersted Laboratory, Universitetsparken 5, DK-2100 Copenhagen (Denmark)

    2004-01-01

    Magnesium atoms are cooled in a magneto-optical trap(MOT) using the 3s{sup 21}S{sub 0} {yields} 3s3p{sup 1}P{sub 1} resonance transition. Magnesium is a simple atom which offers a unique possibility for comparison to the Doppler theory of laser cooling. We measure trap parameters as a function of laser-intensity, -detuning and magnetic field gradient. We find the main features well accounted for by Doppler theory, but temperature measurements gave significant higher values than predicted by the Doppler theory. We also observe radiation pressure effects within the MOT that limit the maximum achievable density. Comparing our results to predictions by models in the literature shows a good agreement. Recently we have improved our set-up and now trap about 150 x 10{sup 6} atoms.

  13. Investigation of the setting reaction in magnesium phosphate ceramics with quasielastic neutron scattering

    Czech Academy of Sciences Publication Activity Database

    Viani, Alberto; Zbiri, M.; Bordallo, H. N.; Gualtieri, A. F.; Mácová, Petra

    2017-01-01

    Roč. 121, č. 21 (2017), s. 11355-11367 ISSN 1932-7447 R&D Projects: GA MŠk(CZ) LO1219 Keywords : magnesium potassium phosphate ceramics * amorphous materials * NMR-spectroscopy Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 4.536, year: 2016 http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.7b01396

  14. Investigation of setting reaction in magnesium potassium phosphate ceramics with time resolved infrared spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Mácová, Petra; Viani, Alberto

    2017-01-01

    Roč. 205, October (2017), s. 62-66 ISSN 0167-577X R&D Projects: GA MŠk(CZ) LO1219 Keywords : amorphous materials * magnesium potassium phosphate cements * FTIR Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 2.572, year: 2016 http://www.sciencedirect.com/science/article/pii/S0167577X17309552

  15. Magnesium, magnesium alloys, and magnesium composites

    National Research Council Canada - National Science Library

    Gupta, M; Sharon, Nai Mui Ling

    2011-01-01

    "Properties of Magnesium Composites for Material Scientists, Engineers and Selectors is the first book-length reference to provide an insight into current and future magnesium-based materials in terms...

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

    DEFF Research Database (Denmark)

    Ostenfeld, Christopher Worsøe; Chorkendorff, Ib

    2006-01-01

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

  17. Composition dependence of structural, magnetic and electrical properties of Co substituted magnesium ferrite

    Science.gov (United States)

    Ramarao, K.; Rajesh Babu, B.; Kishore Babu, B.; Veeraiah, V.; Ramarao, S. D.; Rajasekhar, K.; Venkateswara Rao, A.

    2018-01-01

    In this work cobalt substituted magnesium spinel ferrite having general formula Mg1-xCoxFe2O4 (where x = 0.0, 0.1, 0.15,0.2,0.25 and 0.3) was synthesized by solid state reaction method. All the sample are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Vibrating sample magnetometer (VSM) and dc resistivity measurements. XRD analysis confirms the formation of single phase spinel and the calculated lattice constant 'aexp' from XRD decreases as substitution of Co (x) is increased. The FTIR spectra reveled two prominent frequency bands in the wave number range 400-600 cm-1, which confirm the cubic spinel structure. Magnetic studies revealed that the saturation magnetization attains a maximum value when x = 0.2, and then decreases for higher concentration of (x). This non-linear trend in magnetization has been explained on the basis of redistribution of magnetic and non-magnetic cations among A and B sites of the spinel lattice. A significant influence of cation distribution observed on DC electrical resistivity and activation energy.

  18. Investigating deformation processes in AM60 magnesium alloy using the acoustic emission technique

    Energy Technology Data Exchange (ETDEWEB)

    Mathis, K. [Department of Metal Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Chmelik, F. [Department of Metal Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic)]. E-mail: chmelik@met.mff.cuni.cz; Janecek, M. [Department of Metal Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Hadzima, B. [Department of Materials Engineering, University of Zilina, Vel' ky diel, 010 26 Zilina (Slovakia); Trojanova, Z. [Department of Metal Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Lukac, P. [Department of Metal Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic)

    2006-12-15

    Microstructure changes in an AM60 magnesium alloy were monitored using the acoustic emission (AE) technique during tensile tests in the temperature range from 20 to 300 deg. C. The correlation of the AE signal and the deformation processes is discussed. It is shown, using transmission electron and light microscopy, that the character of the AE response is associated with various modes of mechanical twinning at lower temperatures, whereas at higher temperatures also the influence of non-basal dislocations on the AE response must be taken into account.

  19. Magnesium for Hydrogen Storage

    DEFF Research Database (Denmark)

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

    1980-01-01

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

  20. Nutrition and magnesium absorption

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

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

  1. Magnesium Hydroxide

    Science.gov (United States)

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

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

    KAUST Repository

    Wu, Xiaozhi

    2013-10-25

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

  3. Distinction between magnesium diboride and tetraboride by kelvin probe force microscopy

    International Nuclear Information System (INIS)

    Kim, Du-Na; Caron, Arnaud; Park, Hai Woong

    2016-01-01

    We analyze mixtures of magnesium diboride and tetraboride synthesized with magnesium powders of different shapes. To distinguish between magnesium diboride and tetraboride we use the contrast of kelvin probe force microscopy. The microstructural morphology strongly depends on the shape of the magnesium powders used in the reaction between magnesium and magnesium tetraboride to form magnesium diboride. With spherical magnesium powder an equiaxed microstructure of magnesium diboride is formed with residual magnesium tetraboride at the grain boundaries. With plate-like magnesium powders elongated magnesium diboride grains are formed. In this case, residual magnesium tetraboride is found to agglomerate.

  4. Disruption of an M. tuberculosis membrane protein causes a magnesium-dependent cell division defect and failure to persist in mice.

    Directory of Open Access Journals (Sweden)

    Nichole Goodsmith

    2015-02-01

    Full Text Available The identification of Mycobacterium tuberculosis genes necessary for persistence in vivo provides insight into bacterial biology as well as host defense strategies. We show that disruption of M. tuberculosis membrane protein PerM (Rv0955 resulted in an IFN-γ-dependent persistence defect in chronic mouse infection despite the mutant's near normal growth during acute infection. The perM mutant required increased magnesium for replication and survival; incubation in low magnesium media resulted in cell elongation and lysis. Transcriptome analysis of the perM mutant grown in reduced magnesium revealed upregulation of cell division and cell wall biosynthesis genes, and live cell imaging showed PerM accumulation at the division septa in M. smegmatis. The mutant was acutely sensitive to β-lactam antibiotics, including specific inhibitors of cell division-associated peptidoglycan transpeptidase FtsI. Together, these data implicate PerM as a novel player in mycobacterial cell division and pathogenesis, and are consistent with the hypothesis that immune activation deprives M. tuberculosis of magnesium.

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

    International Nuclear Information System (INIS)

    Denis, Pablo A.; Iribarne, Federico

    2014-01-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

  8. Investigation of organic solvents assisted nano magnesium oxide nanoparticles and their structural, morphological, optical and antimicrobial performance

    Science.gov (United States)

    Deepa, B.; Rajendran, V.

    2018-01-01

    Investigation on the structural, morphological, optical studies and antimicrobial performance of organic solvent assisted magnesium oxide (MgO) nanoparticles. Nanoparticles are in 16–18 nm of grain size prepared by sol–gel method. The XRD studies shows as synthesized products are in cubic phase with periclase structurer. The well disperesd spherical morphology were obtained in SEM and TEM. The organic solvent methanol had profound effects on the size of the nano particles. The optical absorption edge energy was present in UV region and the corresponding band gap energy values are 4.5 and 4.9 eV for water with ethanol and methanol mediated MgO sample respectively. The PL emission spectrum has a emission peak at 340 and 353 nm which is due to surface defects. The obtained MgO nanoparticles showed superior antimicrobial activities for the gram positive, gram negative and fungus strains using the ELISA reader at 450 nm.

  9. Chemical stabilisation of lead in shooting range soils with phosphate and magnesium oxide: Synchrotron investigation

    Energy Technology Data Exchange (ETDEWEB)

    Sanderson, Peter [Centre for Environmental Risk Assessment and Remediation and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), University of South Australia, University Parade, 5095 Mawson Lakes (Australia); Naidu, Ravi, E-mail: ravi.naidu@crccare.com [Centre for Environmental Risk Assessment and Remediation and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), University of South Australia, University Parade, 5095 Mawson Lakes (Australia); Bolan, Nanthi [Centre for Environmental Risk Assessment and Remediation and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), University of South Australia, University Parade, 5095 Mawson Lakes (Australia); Lim, Jung Eun; Ok, Yong Sik [Korea Biochar Research Center & Department of Biological Environment, Kangwon National University, Chuncheon 200-701 (Korea, Republic of)

    2015-12-15

    Highlights: • Quantitative speciation of Pb by XAS as a result of Phosphate and MgO treatment revealed Pb converted to pyromorphite was limited. • Subsequent MgO addition increased pyromorphite formation. • Pb was precipitated on the surface of MgO as PbO. • Bioaccessibility of Pb decreased with P treatments, but not with MgO only. - Abstract: Three Australian shooting range soils were treated with phosphate and magnesium oxide, or a combination of both to chemically stabilize Pb. Lead speciation was determined after 1 month ageing by X-ray absorption spectroscopy combined with linear combination fitting in control and treated soils. The predominant Pb species in untreated soils were iron oxide bound Pb, humic acid bound Pb and the mineral litharge. Treatment with phosphate resulted in substantial pyromorphite formation in two of the soils (TV and PE), accounting for up to 38% of Pb species present, despite the addition of excess phosphate. In MgO treated soils only, up to 43% of Pb was associated with MgO. Litharge and Pb hydroxide also formed as a result of MgO addition in the soils. Application of MgO after P treatment increased hydroxypyromorphite/pyromorphite formation relative to soils teated with phosphate only. X-ray diffraction and Scanning electron microscopy revealed PbO precipitate on the surface of MgO. Soil pH, (5.3–9.3) was an important parameter, as was the solubility of existing Pb species. The use of direct means of determination of the stabilisation of metals such as by X-ray absorption spectroscopy is desirable, particularly in relation to understanding long term stability of the immobilised contaminants.

  10. Magnesium and Osteoporosis

    OpenAIRE

    Ferda Özdemir; Meliha Rodoplu

    2004-01-01

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

  11. Concentration-dependent behaviors of bone marrow derived mesenchymal stem cells and infectious bacteria toward magnesium oxide nanoparticles.

    Science.gov (United States)

    Wetteland, Cheyann Lee; Nguyen, Nhu-Y Thi; Liu, Huinan

    2016-04-15

    This article reports the quantitative relationship between the concentration of magnesium oxide (MgO) nanoparticles and its distinct biological activities towards mammalian cells and infectious bacteria for the first time. The effects of MgO nanoparticles on the viability of bone marrow derived mesenchymal stem cells (BMSCs) and infectious bacteria (both gram-negative Escherichia coli and gram-positive Staphylococcus epidermidis) showed a concentration-dependent behavior in vitro. The critical concentrations of MgO nanoparticles identified in this study provided valuable guidelines for biomaterial design toward potential clinical translation. BMSCs density increased significantly when cultured in 200μg/mL of MgO in comparison to the Cells Only control without MgO. The density of BMSCs decreased significantly after culture in the media with 500μg/mL or more of MgO. Concentrations at or above 1000μg/mL of MgO resulted in complete BMSCs death. Quantification of colony forming units (CFU) revealed that the minimum bactericidal concentration (MBC) of MgO for E. coli and S. epidermidis was 1200μg/mL. The addition of MgO nanoparticles into the cultures increased the pH and Mg(2+) ion concentration in the respective culture media, which might have played a role in the observed cell responses but not the main factors. E. coli and S. epidermidis still proliferated significantly at alkaline pH up to 10 or with supplemental Mg(2+) dosages up to 50mM, indicating bactericidal properties of MgO are beyond the effects of increased media pH and Mg(2+) ion concentrations. MgO nanoparticles at a concentration of 200μg/mL provided dual benefits of promoting BMSC proliferation while reducing bacterial adhesion, which should be further studied for potential medical implant applications. The use of free MgO nanoparticles yielded detrimental effects to BMSCs in concentrations above 300μg/mL. We recommend further study into MgO nanoparticle as a coating material or as a part of a

  12. FOCUS ON MAGNESIUM BASED DRUGS

    Directory of Open Access Journals (Sweden)

    I. I. Esenova

    2011-01-01

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

  13. Magnesium-dependent non-specific binding of [125I]prolactin to myelinated tracts in the rat central nervous system

    International Nuclear Information System (INIS)

    Mangurian, L.P.; Walsh, R.J.; Posner, B.I.

    1989-01-01

    An in vitro autoradiographic assay was used in identifying a magnesium-dependent, non-specific binding of [ 125 I] prolactin to myelinated fiber tracts in the rat brain. Frozen tissue sections were incubated for 18 h at 4 degrees C in media which included [ 125 I]prolactin alone or with a 500 fold excess of unlabelled prolactin. Magnesium in the incubation medium caused a non-specific binding of radiolabelled prolactin to the myelinated fiber tracts in the brain. In contrast, calcium did not facilitate prolactin non-specific binding to myelin. Hence, calcium should optimize the detection of specific prolactin binding sites in the brain by in vitro autoradiographic or radioreceptor assays

  14. Magnesium, magnesium alloys, and magnesium composites

    National Research Council Canada - National Science Library

    Gupta, M; Sharon, Nai Mui Ling

    2011-01-01

    ... of science, characteristics, and applications. It emphasizes the properties of magnesium-based composites and the effects of different types of reinforcements, from micron length to nanometer scale, on the properties of the resulting composites...

  15. Magnesium, magnesium alloys, and magnesium composites

    National Research Council Canada - National Science Library

    Gupta, M; Sharon, Nai Mui Ling

    2011-01-01

    .... With the popularity of magnesium-based materials in the automotive, aerospace, electronics, and sports equipment industries, and its unique role as a lightweight, energy-saving and high-performance...

  16. In-depth investigation on physicochemical and thermal properties of magnesium (II gluconate using spectroscopic and thermoanalytical techniques

    Directory of Open Access Journals (Sweden)

    Mahendra Kumar Trivedi

    2017-10-01

    Full Text Available Magnesium gluconate is a classical organometallic pharmaceutical compound used for the prevention and treatment of hypomagnesemia as a source of magnesium ion. The present research described the in-depth study on solid state properties viz. physicochemical and thermal properties of magnesium gluconate using sophisticated analytical techniques like PXRD, PSA, FT-IR, UV–Vis spectroscopy, TGA/DTG, and DSC. Magnesium gluconate was found to be crystalline in nature along with the crystallite size ranging from 14.10 to 47.35 nm. The particle size distribution was at d(0.1=6.552 µm, d(0.5=38.299 µm, d(0.9=173.712 µm and D(4,3=67.122 µm along with the specific surface area of 0.372 m2/g. The wavelength for the maximum absorbance was at 198.0 nm. Magnesium gluconate exhibited 88.51% weight loss with three stages of thermal degradation process up to 895.18 °C from room temperature. The TGA/DTG thermograms of the analyte indicated that magnesium gluconate was thermally stable up to around 165 °C. Consequently, the melting temperature of magnesium gluconate was found to be 169.90 °C along with the enthalpy of fusion of 308.7 J/g. Thus, the authors conclude that the achieved results from this study are very useful in pharmaceutical and nutraceutical industries for the identification, characterization and qualitative analysis of magnesium gluconate for preformulation studies and also for developing magnesium gluconate based novel formulation.

  17. In-depth investigation on physicochemical and thermal properties of magnesium (II) gluconate using spectroscopic and thermoanalytical techniques.

    Science.gov (United States)

    Trivedi, Mahendra Kumar; Dixit, Neena; Panda, Parthasarathi; Sethi, Kalyan Kumar; Jana, Snehasis

    2017-10-01

    Magnesium gluconate is a classical organometallic pharmaceutical compound used for the prevention and treatment of hypomagnesemia as a source of magnesium ion. The present research described the in-depth study on solid state properties viz. physicochemical and thermal properties of magnesium gluconate using sophisticated analytical techniques like PXRD, PSA, FT-IR, UV-Vis spectroscopy, TGA/DTG, and DSC. Magnesium gluconate was found to be crystalline in nature along with the crystallite size ranging from 14.10 to 47.35 nm. The particle size distribution was at d(0.1)=6.552 µm, d(0.5)=38.299 µm, d(0.9)=173.712 µm and D(4,3)=67.122 µm along with the specific surface area of 0.372 m 2 /g. The wavelength for the maximum absorbance was at 198.0 nm. Magnesium gluconate exhibited 88.51% weight loss with three stages of thermal degradation process up to 895.18 °C from room temperature. The TGA/DTG thermograms of the analyte indicated that magnesium gluconate was thermally stable up to around 165 °C. Consequently, the melting temperature of magnesium gluconate was found to be 169.90 °C along with the enthalpy of fusion of 308.7 J/g. Thus, the authors conclude that the achieved results from this study are very useful in pharmaceutical and nutraceutical industries for the identification, characterization and qualitative analysis of magnesium gluconate for preformulation studies and also for developing magnesium gluconate based novel formulation.

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

    International Nuclear Information System (INIS)

    Hasni, Abdellatif

    1988-01-01

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

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

    DEFF Research Database (Denmark)

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

    2006-01-01

    The dehydrogenation kinetics of pure and nickel (Ni)-doped (2w/w%) magnesium hydride (MgH2) have been investigated by in situ time-resolved powder X-ray diffraction (PXD). Deactivated samples, i.e. air exposed, are investigated in order to focus on the effect of magnesium oxide (MgO) surface layers......, which might be unavoidable for magnesium (Mg)-based storage media for mobile applications. A curved position-sensitive detector covering 120 degrees in 20 and a rotating anode X-ray source provide a time resolution of 45 s and up to 90 powder pattems collected during an experiment under isothermal...... by the Johnson-Mehi-Avrami formalism in order to derive rate constants at different temperatures. The apparent activation energies for dehydrogenation of pure and Ni-doped magnesium hydride were E-A approximate to 300 and 250 kJ/mol, respectively. Differential scanning calorimetry gave, E-A = 270 k...

  20. Magnesium Test

    Science.gov (United States)

    ... and Iron-binding Capacity (TIBC, UIBC) Trichomonas Testing Triglycerides Troponin Tryptase Tumor Markers Uric Acid Urinalysis Urine ... numbness or tingling. They can also affect calcium metabolism and exacerbate calcium deficiencies. Symptoms of excess magnesium ...

  1. Production of magnesium metal

    Science.gov (United States)

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

    2010-02-23

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

  2. Thermodynamic investigation of the effect of alkali metal impuries on the processing of aluminum and magnesium alloys

    Science.gov (United States)

    Zhang, Shengjun

    2006-12-01

    Aluminum and magnesium alloys are widely used in the automobile and aerospace industries as structural materials due to their light weight, high specific strength and good formability. However, they suffer from the poor hot rolling characteristics due to undesired impurities like calcium, potassium, lithium and sodium. They increase the hydrogen solubility in the melt and promote the formation of porosity in aluminum castings. During fabrication of aluminum alloys, they cause the hot-shortness and embrittlement due to cracking. They also led to "blue haze" corrosion which promotes the discoloration of aluminum under humid condition. The removal of these elements increases overall melt loss of aluminum alloys when aluminum products are remelted and recast. Na is one of the common impurities in the Al and Mg alloys. In industry, primary Al is produced by the Hall-Heroult process, through the electrolysis of the mixture of molten alumina and cryolite (Al2O3+Na 3AlF6), the latter being added to lower the melting point. Therefore, Al inevitably contains some Na (>0.002%) without further treatment. The Na content in Al is influenced by the thermodynamics and kinetics of the electrolysis. Similarly, in the electrolytic production and subsequent processing of Mg, Mg is commonly in contact with molten salt mixtures of NaCl and MgCl 2. Consequently, 2--20 wt. ppm Na is often found in Mg alloys. Besides originating from the industrial production process, Na can be introduced in laboratory experiments from alumina crucibles by the reaction between the molten Al-Mg alloys and the Na2O impurity in the alumina crucible. The trace element K plays a similar role in Al alloys although it is seldom discussed. No systematic theoretic research has been carried out to investigate the behavior of these impurities during the processing of aluminum alloys. The thermodynamic description of the Al-Ca-K-Li-Mg-Na system is needed to understand the effects of Ca, K, Li and Na on phase stability

  3. Function of magnesium aluminate hydrate and magnesium nitrate ...

    Indian Academy of Sciences (India)

    MgO was added both as spinel (MgAl2O4) forming precursor i.e. magnesium aluminate hydrate, and magnesium nitrate. Sintering investigations were conducted in the temperature range 1500–1600°C with 2 h soaking. Structural study of sintered pellets was carried out by extensive XRD analysis. Scanning electron mode ...

  4. Preclinical investigation of an innovative magnesium-based bone graft substitute for potential orthopaedic applications

    Directory of Open Access Journals (Sweden)

    Chen Liu

    2014-07-01

    Full Text Available Degradable or corrosive biometal is an attractive research and development (R&D area in clinical orthopaedics. This study was designed to investigate biomechanical and biological properties of magnesium (Mg and strontium (Sr with a focus on Mg-based metals, including pure Mg and Mg–xwt% Sr (x = 0.25, x = 1.0, x = 1.5, x = 2.5 alloys, as potential bone graft substitutes in respect to their mechanical strength, corrosion resistance, and cytocompatibility for further optimization and establishing indications for relevant in vivo applications. Our data showed that the tensile and compressive strength increased with addition of Sr because of the Mg17Sr2 precipitation strengthen. Compared with commercially used bone graft substitutes, the mechanical properties of Mg–Sr alloys were close to those of cortical bone, and the compressive strength could reach 300 MPa, suggesting its potential application for load-bearing bone as bone defect filler. The corrosion rates of Mg–xwt% Sr alloys were controlled in the range of 0.05–0.07 mm/y, indicating feasibility of bone grafting and the in situ bone repair process. Moreover, Mg–Sr alloys also exhibit good cytocompatibility and antibacterial properties. Our innovation presented in this work supported in vivo clinical indication-based assessment of biodegradable Mg-based metals that could be potential candidates for bone graft substitutes for future orthopaedic applications.

  5. In situ neutron diffraction investigation of deformation twinning and pseudoelastic-like behaviour of extruded AZ31 magnesium alloy

    Czech Academy of Sciences Publication Activity Database

    Muránsky, O.; Carr, D.G.; Šittner, Petr; Oliver, E.C.

    2009-01-01

    Roč. 25, č. 6 (2009), s. 1107-1127 ISSN 0749-6419 Institutional research plan: CEZ:AV0Z10100520 Keywords : psudoelasticity * magnesium * twinning-untwinning * deformation mechanism * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.791, year: 2009

  6. INVESTIGATION FOR THE INFLUENCE OF DIFFERENT MAGNESIUM SULFATE DOSES ON THE CONTENT OF CALCIUM AND CHLORIDE IN BLOOD SERUM OF RATS OF BOTH GENDERS

    Directory of Open Access Journals (Sweden)

    A. V. Voronkov

    2016-01-01

    Full Text Available We have conducted an investigation for the influence of different magnesium sulfate doses on the content of calcium and chloride in blood serum of rats of both genders. As the result of the study, we have established that peroral administration of magnesium sulfate at dose 1.7 g/kg leads to the significant decrease of chlorides content in blood serum of male rats, concerning the control group of animals, and at dose 5 g/kg to the decrease of concentration, chloride as well as calcium in rats of both genders.

  7. 76 FR 69284 - Pure Magnesium From China

    Science.gov (United States)

    2011-11-08

    ... COMMISSION Pure Magnesium From China Determination On the basis of the record \\1\\ developed in the subject... order on pure magnesium from China would be likely to lead to continuation or recurrence of material... USITC Publication 4274 (October 2011), entitled Pure Magnesium from China: Investigation No. 731-TA-696...

  8. Magnesium compounds

    Science.gov (United States)

    Kramer, D.A.

    2012-01-01

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

  9. Reaction Kinetics with Hydrogen and Temperature Dependence of the Hydriding Rate for a Magnesium-Based Nickel Iron Oxide Alloy

    International Nuclear Information System (INIS)

    Song, Myoung Youp; Baek, Sung Hwan; Park, Hye Ryoung

    2012-01-01

    A 71.5 wt%Mg-23.5 wt%Ni-5 wt%Fe 2 O 3 (Mg-23.5Ni-5Fe 2 O 3 ) sample was prepared by a quite simple process, reactive mechanical grinding, and its hydriding and dehydriding properties were then investigated. The reactive mechanical grinding of Mg with Ni and Fe 2 O 3 is considered to facilitate nucleation and shorten the diffusion distances of the hydrogen atoms. After the hydriding-dehydriding cycling, the Mg-23.5Ni-5Fe 2 O 3 sample contained Mg 2 Ni phase. Expansion and contraction of the hydride-forming materials (Mg and Mg 2 Ni) with the hydriding and dehydriding reactions are also considered to increase the hydriding and dehydriding rates of the mixture by forming defects and cracks leading to the fragmentation of the particles. The temperature dependence of the hydriding rate of the sample is discussed.

  10. Anticorrosive magnesium hydroxide coating on AZ31 magnesium alloy by hydrothermal method

    International Nuclear Information System (INIS)

    Zhu Yanying; Wu Guangming; Xing Guangjian; Li Donglin; Zhao Qing; Zhang Yunhong

    2009-01-01

    Magnesium alloys are potential biodegradable biomaterials in orthopedic surgery. However, the rapid degradation rate has limited their application in biomedical field. A great deal of studies have been done to improve the resistance of magnesium alloys. In this article, An anticorrosive magnesium hydroxide coating with a thickness of approximately 100μm was formed on an AZ31 magnesium alloy by hydrothermal method. The morphology of the coatings were observed by an optical microscope and SEM. And the samples were soaked in hank's solution (37 deg. C) to investigate the corrosion resistance. Magnesium alloy AZ31 with magnesium hydroxide coatings present superior corrosion resistance than untreated samples.

  11. Regulation of magnesium balance: lessons learned from human genetic disease

    OpenAIRE

    de Baaij, Jeroen H. F.; Hoenderop, Joost G. J.; Bindels, Ren? J. M.

    2012-01-01

    Magnesium (Mg2+) is the fourth most abundant cation in the body. Thus, magnesium homeostasis needs to be tightly regulated, and this is facilitated by intestinal absorption and renal excretion. Magnesium absorption is dependent on two concomitant pathways found in both in the intestine and the kidneys: passive paracellular transport via claudins facilitates bulk magnesium absorption, whereas active transcellular pathways mediate the fine-tuning of magnesium absorption. The identification of g...

  12. Higher dietary magnesium intake and higher magnesium status are associated with lower prevalence of coronary heart disease in patients with type 2 diabetes

    NARCIS (Netherlands)

    Gant, C.M.; Soedamah-Muthu, S.S.; Binnenmars, S.H.; Bakker, S.J.L.; Navis, G.; Laverman, G.D.

    2018-01-01

    In type 2 diabetes mellitus (T2D), the handling of magnesium is disturbed. Magnesium deficiency may be associated with a higher risk of coronary heart disease (CHD). We investigated the associations between (1) dietary magnesium intake; (2) 24 h urinary magnesium excretion; and (3) plasma magnesium

  13. Analysis of flow stress and deformation mechanism under hot working of ZK60 magnesium alloy by a new strain-dependent constitutive equation

    Science.gov (United States)

    Ciccarelli, D.; El Mehtedi, M.; Jäger, A.; Spigarelli, S.

    2015-12-01

    The present study investigates the variation of flow stress and microstructural evolution with strain for ZK60 magnesium alloy. A new constitutive equation was used to model the flow stress with excellent results. This constitutive analysis and the microstructural studies carried out on strained samples revealed the existence of two different regimes. At temperatures above 300 °C, moderate grain growth and intragranular dislocation activity. Yet, the calculated value of the activation energy and the marked increase in the equivalent strain to fracture indicated grain boundary sliding as a dominant mechanism in this regime of strain rate and temperature, with dislocation motion playing an ancillary role. At lower temperatures, deformation was exclusively governed by dislocation motion, with the extensive occurrence of dynamic recrystallization, which started at low strains, and absence of grain growth.

  14. A Double-Blind Randomized Placebo Controlled Trial of Magnesium Oxide for Alleviation of Chronic Low Back Pain

    Science.gov (United States)

    1999-10-01

    relationship of magnesium. Another extensively investigated clinical problem related to magnesium research is migraine headaches. Altura (1985) hypothesized... Altura , Cracco, and B. M. Altura (1992), the researchers assessed total serum magnesium, serum ionized magnesium levels, percent ionized magnesium...not be an accurate measure when assessing magnesium balance. Mauskop, B. T. Altura , Cracco, and B. M. Altura (1995) conducted a similar study while

  15. Magnesium in diet

    Science.gov (United States)

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

  16. Low magnesium level

    Science.gov (United States)

    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, ...

  17. Investigation of Electrochemical Studies of Magnesium Ion Conducting Poly(vinyl alcohol)-Poly(vinyl pyrrolidone) Based Blend Polymers.

    Science.gov (United States)

    Jeyabanu, K; Siva, V; Nallamuthu, N; Selvanayagam, S; Bahadur, S Asath; Manikandan, A

    2018-02-01

    Polymer blend electrolytes based on magnesium ion conducting PVA-PVP-MgCl2 polymer were prepared at different compositions by solution casting techniques. The prepared films were characterised by various techniques such as XRD and FTIR. Amorphous nature and structural coordination of polymer electrolyte were confirmed by X-ray diffraction and Fourier transform infrared spectroscopy studies. The ionic conductivity of the prepared polymer electrolytes were analysed through ac impedance spectroscopy. The highest conductivity was found to be in the order of ~10-6 Scm-1 at an ambient temperature for the composition of 50PVA:50PVP:5 wt% MgCl2. Conductivity versus temperature plot was found to follow an Arrhenius nature. The dielectric behaviour and ionic transport properties of the polymer electrolytes were also analyzed.

  18. MicroRaman, PXRD, EDS and microscopic investigation of magnesium calcite biomineral phases. The case of sea urchin biominerals

    Science.gov (United States)

    Borzęcka-Prokop, B.; Wesełucha-Birczyńska, A.; Koszowska, E.

    2007-02-01

    This study concerns Mg-calcite characterization (and in particular molecular structure and microstructural studies of mineral phases) of a sea urchin mineralised test and spines. Sea urchins are spiny sea animals (kingdom Animalia, phylum Echinodermata, class Echinoidea). Microscopic observations, SEM, EDS, PXRD and spectroscopic microRaman methods have been applied to characterize the biomineral parts of the sea urchin. The latter technique is very useful in research of biological systems and especially suitable for monitoring differences within biomineral phases exhibiting varieties of morphological forms. Crystalline magnesium calcium carbonate, Mg xCa 1- xCO 3 (magnesian calcite; space group R-3 cH; a = 4.9594(8) Å, c = 16.886(6) Å), has been identified as the predominant biomineral component.

  19. Magnesium: Nutrition and Homoeostasis

    OpenAIRE

    Jürgen Vormann

    2016-01-01

    The essential mineral magnesium is involved in numerous physiological processes. Recommended dietary intake is often not met and a low magnesium status increases the risk for various diseases. Magnesium status is regulated by several magnesium transport systems either in cellular or paracellular pathways. Numerous drugs either interfere with magnesium absorption in the intestines or the reabsorption from primary urine in the kidney. Low magnesium status has been identified as a significant ri...

  20. Magnesium tube hydroforming

    Energy Technology Data Exchange (ETDEWEB)

    Liewald, M.; Pop, R. [Institute for Metal Forming Technology (IFU), Stuttgart (Germany)

    2008-04-15

    Magnesium alloys reveal a good strength-to-weight ratio in the family of lightweight metals and gains potential to provide up to 30% mass savings compared to aluminium and up to 75 % compared to steel. The use of sheet magnesium alloys for auto body applications is however limited due to the relatively low formability at room temperature. Within the scope of this paper, extruded magnesium tubes, which are suitable for hydroforming applications, have been investigated. Results obtained at room temperature using magnesium AZ31 tubes show that circumferential strains are limited to a maximal value of 4%. In order to examine the influence of the forming temperature on tube formability, investigations have been carried out with a new die set for hot internal high pressure (IHP) forming at temperatures up to 400 C. Earlier investigations with magnesium AZ31 tubes have shown that fractures occur along the welding line at tubes extruded over a spider die, whereby a non-uniform expansion at bursting with an elongation value of 24% can be observed. A maximum circumferential strain of approx. 60% could be attained when seamless, mechanically pre-expanded and annealed tubes of the same alloy have been used. The effect of annealing time on materials forming properties shows a fine grained structure for sufficient annealing times as well as deterioration with a large increase at same time. Hence, seamless ZM21 tubes have been used in the current investigations. With these tubes, an increased tensile fracture strain of 116% at 350 C is observed as against 19% at 20 C, obtained by tensile testing of milled specimens from the extruded tubes. This behaviour is also seen under the condition of tool contact during the IHP forming process. To determine the maximum circumferential strain at different forming temperatures and strain rates, the tubes are initially bulged in a die with square cross-section under plane stress conditions. Thereafter, the tubes are calibrated by using an

  1. Microstructure and mechanical properties of selective laser melted magnesium

    International Nuclear Information System (INIS)

    Ng, C.C.; Savalani, M.M.; Lau, M.L.; Man, H.C.

    2011-01-01

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

  2. Magnesium prevents phosphate-induced vascular calcification via TRPM7 and Pit-1 in an aortic tissue culture model.

    Science.gov (United States)

    Sonou, Tomohiro; Ohya, Masaki; Yashiro, Mitsuru; Masumoto, Asuka; Nakashima, Yuri; Ito, Teppei; Mima, Toru; Negi, Shigeo; Kimura-Suda, Hiromi; Shigematsu, Takashi

    2017-06-01

    Previous clinical and experimental studies have indicated that magnesium may prevent vascular calcification (VC), but mechanistic characterization has not been reported. This study investigated the influence of increasing magnesium concentrations on VC in a rat aortic tissue culture model. Aortic segments from male Sprague-Dawley rats were incubated in serum-supplemented high-phosphate medium for 10 days. The magnesium concentration in this medium was increased to demonstrate its role in preventing VC, which was assessed by imaging and spectroscopy. The mineral composition of the calcification was analyzed using Fourier transform infrared (FTIR) spectroscopic imaging, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) mapping. Magnesium supplementation of high-phosphate medium dose-dependently suppressed VC (quantified as aortic calcium content), and almost ablated it at 2.4 mm magnesium. The FTIR images and SEM-EDX maps indicated that the distribution of phosphate (as hydroxyapatite), phosphorus and Mg corresponded with calcium content in the aortic ring and VC. The inhibitory effect of magnesium supplementation on VC was partially reduced by 2-aminoethoxy-diphenylborate, an inhibitor of TRPM7. Furthermore, phosphate transporter-1 (Pit-1) protein expression was increased in tissues cultured in HP medium and was gradually-and dose dependently-decreased by magnesium. We conclude that a mechanism involving TRPM7 and Pit-1 underpins the magnesium-mediated reversal of high-phosphate-associated VC.

  3. Magnesium borate radiothermoluminescent detectors

    International Nuclear Information System (INIS)

    Kazanskaya, V.A.; Kuzmin, V.V.; Minaeva, E.E.; Sokolov, A.D.

    1974-01-01

    In the report the technology of obtaining polycrystalline magnesium borate activated by dysprosium is described briefly and the method of preparing the tabletted detectors from it is presented. The dependence of the light sum of the samples on the proportion of the components and on the sintering regime has shown that the most sensitive material is obtained at the proportion of boric anhydride and magnesium oxide 2.2-2.4 and at the dysprosium concentration about 1 milligram-atom per gram molecule of the base. The glow curve of such a material has a simple form with one peak the maximum of which is located at 190-200 0 C. The measurement of the main dosimetric characteristics of the magnesium borate tabletted detectors and the comparison with similar parmaeters of the lithium fluoride tabletted detectors have shown that at practically identical effective number the former detectors have the following substantial advantages: the sensitivity is ten-twenty times as large, they are substantially more technological on synthesis of the radiothermoluminophor and during the production of the tabletted detectors, they have a simple glow curve, they do not require the utilization of the thermocycling during the use. (author)

  4. Magnesium: Nutrition and Homoeostasis

    Directory of Open Access Journals (Sweden)

    Jürgen Vormann

    2016-05-01

    Full Text Available The essential mineral magnesium is involved in numerous physiological processes. Recommended dietary intake is often not met and a low magnesium status increases the risk for various diseases. Magnesium status is regulated by several magnesium transport systems either in cellular or paracellular pathways. Numerous drugs either interfere with magnesium absorption in the intestines or the reabsorption from primary urine in the kidney. Low magnesium status has been identified as a significant risk factor for several diseases, including type-2 diabetes, cardiovascular diseases, arrhythmias, as well as general muscular and neurological problems. Therefore, an adequate magnesium supply would be of special benefit to our overall health.

  5. Investigation of the Effect of Magnesium on the Microstructure and Mechanical Properties of NiTi Shape Memory Alloy Prepared by Self-Propagating High-Temperature Synthesis

    Science.gov (United States)

    Školáková, Andrea; Novák, Pavel; Salvetr, Pavel; Moravec, Hynek; Šefl, Václav; Deduytsche, Davy; Detavernier, Christophe

    2017-07-01

    This work aims to describe the effect of magnesium on the microstructure, phase composition, amount of undesirable Ti2Ni phase, martensitic transformation, mechanical properties, and corrosion resistance of NiTi alloy. To minimize the quantity of Ti2Ni phase, we use the magnesium as an element with high affinity to oxygen, because this phase is stabilized by oxygen. Various quantities of magnesium (1, 3, and 5 wt pct) were tested. Self-propagating high-temperature synthesis (SHS) was used as a production method of the alloys. The samples prepared by SHS were pulverized by a vibrating mill, and the obtained powders were used for consolidation by means of spark plasma sintering. Results showed a significant reduction of the content of undesirable Ti2Ni phase by the addition of magnesium. Further, magnesium increased corrosion resistance and yield strength.

  6. Low Temperature Synthesis of Magnesium Aluminate Spinel

    International Nuclear Information System (INIS)

    Lebedovskaya, E.G.; Gabelkov, S.V.; Litvinenko, L.M.; Logvinkov, D.S.; Mironova, A.G.; Odejchuk, M.A.; Poltavtsev, N.S.; Tarasov, R.V.

    2006-01-01

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

  7. Oxide films on magnesium and magnesium alloys

    International Nuclear Information System (INIS)

    Shih, T.-S.; Liu, J.-B.; Wei, P.-S.

    2007-01-01

    Magnesium alloys are very active and readily ignite during heating and melting. In this study, we discuss the combustion of magnesium and magnesium alloys and propose prospective anti-ignition mechanisms for magnesium alloys during the heating process. When magnesium and magnesium alloys were heated in air, the sample surfaces produced layers of thermally formed oxides. These thermally formed oxides played an important role in affecting the combustion of the magnesium and magnesium alloys. When magnesium was heated in air, brucite that formed in the early stage was then transformed into periclase by dehydroxylation. By extending the heating time, more periclase formed and increased in thickness which was associated with microcracks formation. When magnesium was heated in a protective atmosphere (SF 6 ), a film of MgF 2 formed at the interface between the oxide layer and the Mg substrate. This film generated an anti-ignition behavior which protected the substrate from oxidation. When solution-treated AZ80 alloy was heated, spinel developed at the interface between the thermally formed oxide layer and the Mg substrate, improving the anti-ignition properties of the substrate. In addition, we also explain the effects of beryllium in an AZB91 alloy on the ignition-proofing behavior

  8. The Importance of Magnesium in Clinical Healthcare

    Directory of Open Access Journals (Sweden)

    Gerry K. Schwalfenberg

    2017-01-01

    Full Text Available The scientific literature provides extensive evidence of widespread magnesium deficiency and the potential need for magnesium repletion in diverse medical conditions. Magnesium is an essential element required as a cofactor for over 300 enzymatic reactions and is thus necessary for the biochemical functioning of numerous metabolic pathways. Inadequate magnesium status may impair biochemical processes dependent on sufficiency of this element. Emerging evidence confirms that nearly two-thirds of the population in the western world is not achieving the recommended daily allowance for magnesium, a deficiency problem contributing to various health conditions. This review assesses available medical and scientific literature on health issues related to magnesium. A traditional integrated review format was utilized for this study. Level I evidence supports the use of magnesium in the prevention and treatment of many common health conditions including migraine headache, metabolic syndrome, diabetes, hyperlipidemia, asthma, premenstrual syndrome, preeclampsia, and various cardiac arrhythmias. Magnesium may also be considered for prevention of renal calculi and cataract formation, as an adjunct or treatment for depression, and as a therapeutic intervention for many other health-related disorders. In clinical practice, optimizing magnesium status through diet and supplementation appears to be a safe, useful, and well-documented therapy for several medical conditions.

  9. Magnesium Hydride for Load Levelling Energy Storage

    DEFF Research Database (Denmark)

    Vigeholm, B.

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

  10. Enhancements in Magnesium Die Casting Impact Properties

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-06-30

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

  11. 77 FR 59979 - Pure Magnesium (Granular) From China

    Science.gov (United States)

    2012-10-01

    ... COMMISSION Pure Magnesium (Granular) From China Determination On the basis of the record \\1\\ developed in the... antidumping duty order on pure magnesium (granular) from China would be likely to lead to continuation or...), entitled Pure Magnesium (Granular) from China: Investigation No.731-TA- 895 (Second Review). Issued...

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

    NARCIS (Netherlands)

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

    2007-01-01

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

  13. Study of the loading mode dependence of the twinning in random textured cast magnesium by acoustic emission and neutron diffraction methods

    Czech Academy of Sciences Publication Activity Database

    Čapek, J.; Máthis, K.; Clausen, B.; Stráská, J.; Beran, Přemysl; Lukáš, Petr

    2014-01-01

    Roč. 602, APR (2014), s. 25-32 ISSN 0921-5093 R&D Projects: GA ČR(CZ) GAP204/12/1360 Institutional support: RVO:61389005 Keywords : magnesium * acoustic emission * neutron diffraction * deformation twinning Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.567, year: 2014

  14. Choline Magnesium Trisalicylate

    Science.gov (United States)

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

  15. Magnesium and Space Flight

    Science.gov (United States)

    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

  16. Effect of acute hyperinsulinemia on magnesium homeostasis in humans.

    Science.gov (United States)

    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.

  17. Protein phosphatase magnesium-dependent 1δ (PPM1D mRNA expression is a prognosis marker for hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Guang-Bing Li

    Full Text Available Protein phosphatase magnesium-dependent 1δ (PPM1D is an oncogene, overexpressed in many solid tumors, including ovarian cancer and breast cancer. The current study examined the expression and the prognostic value of PPM1D mRNA in human hepatocellular carcinoma (HCC.Total RNA was extracted from 86 HCC and paired non-cancerous liver tissues. PPM1D mRNA expression was determined by real-time quantitative reverse transcriptase-polymerase chain reaction (qPCR. Immunohistochemistry assay was used to verify the expression of ppm1d protein in the HCC and non-cancerous liver tissues. HCC patients were grouped according to PPM1D mRNA expression with the average PPM1D mRNA level in non-cancerous liver tissue samples as the cut-off. Correlations between clinicopathologic variables, overall survival and PPM1D mRNA expression were analyzed.PPM1D mRNA was significantly higher in HCC than in the paired non-cancerous tissue (p<0.01. This was confirmed by ppm1d staining. 56 patients were classified as high expression group and the other 30 patients were categorized as low expression group. There were significant differences between the two groups in term of alpha-fetoprotein (α-FP level (p<0.01, tumor size (p<0.01, TNM stage (p<0.01, recurrence incidence (p<0.01 and family history of liver cancer (p<0.01. The current study failed to find significant differences between the two groups in the following clinical characteristics: age, gender, portal vein invasion, lymphnode metastasis, hepatitis B virus (HBV infection and alcohol intake. Survival time of high expression group was significantly shorter than that of low expression group (median survival, 13 months and 32 months, respectively, p<0.01.Up-regulation of PPM1D mRNA was associated with progressive pathological feature and poor prognosis in HCC patients. PPM1D mRNA may serve as a prognostic marker in HCC.

  18. Investigating the time-dependent zeta potential of wood surfaces.

    Science.gov (United States)

    Muff, Livius F; Luxbacher, Thomas; Burgert, Ingo; Michen, Benjamin

    2018-05-15

    This work reports on streaming potential measurements through natural capillaries in wood and investigates the cause of a time-dependent zeta potential measured during the equilibration of wood cell-walls with an electrolyte solution. For the biomaterial, this equilibration phase takes several hours, which is much longer than for many other materials that have been characterized by electrokinetic measurements. During this equilibration phase the zeta potential magnitude is decaying due to two parallel mechanisms: (i) the swelling of the cell-wall which causes a dimensional change reducing the charge density at the capillary interface; (ii) the transport of ions from the electrolyte solution into the permeable cell-wall which alters the electrical potential at the interface by internal charge compensation. The obtained results demonstrate the importance of equilibration kinetics for an accurate determination of the zeta potential, especially for materials that interact strongly with the measurement electrolyte. Moreover, the change in zeta potential with time can be correlated with the bulk swelling of wood if the effect of electrolyte ion diffusion is excluded. This study shows the potential of streaming potential measurements of wood, and possibly of other hygroscopic and nanoporous materials, to reveal kinetic information about their interaction with liquids, such as swelling and ion uptake. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. A review on hot tearing of magnesium alloys

    Directory of Open Access Journals (Sweden)

    Jiangfeng Song

    2016-09-01

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

  20. Investigation of Combination Effect of Magnesium Oxide and Iron Oxide Nanoparticles on the Growth And Morphology of the Bacteria Staphylococcus Aureus and Escherichia Coli in Juice

    Directory of Open Access Journals (Sweden)

    mahdi torabi zarchi

    2017-02-01

    Full Text Available Introduction: Nanoparticles (NPs are one of the antibacterial substances, among them nanoparticles type MgO and Fe2O3 are less toxic to mammalian cells. So, the aim of this study was investigation of combination effects of iron oxide and magnesium oxide nanoparticles on the growth of Staphylococcus aureus and Escherichia coli (E.coli to achieve the optimum combination of nanoparticles inhibit the growth of Staphylococcus aureus and Escherichia coli in food (juice. Methods: In this experimental research, the effect of MgO and Fe2O3 Nanoparticles compound on Staphylococcus aureus and Escherichia coli bacteria in liquid environment was investigated, and then their effect was investigated separately in juices of carrot, pomegranate and apple via colony count approach. Also, scanning electron microscopy was used to characterize the morphological changes of Staphylococcus aureus and Escherichia coli after antimicrobial treatments. The results of the research were analyzed using one way ANNOVA. Results: The results of the research indicated that in liquid medium, these nanoparticles lead to reduce the growth of both bacteria. compound of 1.5Mg+0.5Fe2O3 was introduced as the most appropriate antibacterial compounds; Staphylococcus aureus sensitivity to Escherichia coli was higher against nanoparticles. The findings of research about the juices revealed that the combined effect of nanoparticles reduced the growth of both bacteria. the combined effect of Fe2o3 and MgO nanoparticles treatments distorted and damaged the cell membrane, resulting in a leakage of intracellular contents and eventually the death of bacterial cells. Conclusion: Nanoparticles in the allowed concentrations have significant effect on Staphylococcus aureus and Escherichia coli bacteria.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-15

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

  2. Investigation into the Manufacture and Properties of Inhalable High-Dose Dry Powders Produced by Comilling API and Lactose with Magnesium Stearate.

    Science.gov (United States)

    Lau, Michael; Young, Paul M; Traini, Daniela

    2017-08-01

    The aim of the study was to understand the impact of different concentrations of the additive material, magnesium stearate (MGST), and the active pharmaceutical ingredient (API), respectively, on the physicochemical properties and aerosol performance of comilled formulations for high-dose delivery. Initially, blends of API/lactose with different concentrations of MGST (1-7.5% w/w) were prepared and comilled by the jet-mill apparatus. The optimal concentration of MGST in comilled formulations was investigated, specifically for agglomerate structure and strength, particle size, uniformity of content, surface coverage, and aerosol performance. Secondly, comilled formulations with different API (1-40% w/w) concentrations were prepared and similarly analyzed. Comilled 5% MGST (w/w) formulation resulted in a significant improvement in in vitro aerosol performance due to the reduction in agglomerate size and strength compared to the formulation comilled without MGST. Higher concentrations of MGST (7.5% w/w) led to reduction in aerosol performance likely due to excessive surface coverage of the micronized particles by MGST, which led to failure in uniformity of content and an increase in agglomerate strength and size. Generally, comilled formulations with higher concentrations of API increased the agglomerate strength and size, which subsequently caused a reduction in aerosol performance. High-dose delivery was achieved at API concentration of >20% (w/w). The study provided a platform for the investigation of aerosol performance and physicochemical properties of other API and additive materials in comilled formulations for the emerging field of high-dose delivery by dry powder inhalation.

  3. Investigation in magnesium-aluminum-calcium-strontium system by computational thermodynamics approach coupled with first-principles energetics and experiments

    Science.gov (United States)

    Ozturk, Koray

    The thermodynamic database for the Mg-Al-Ca-Sr quaternary system was constructed by combining the thermodynamic descriptions of the constituent binary systems. There are six binaries in the quaternary system: Al-Ca, Al-Mg, Al-Sr, Ca-Sr, Ca-Mg and Mg-Sr. Only two of them had been absent from the databases: Al-Ca and Ca-Sr. Therefore, they were investigated in detail to develop their thermodynamic descriptions. They were evaluated using Thermo-Calc, the software developed at The Royal Institute of Technology, Sweden. It is based on the CALPHAD approach. The modeling in CALPHAD approach relies on the Gibbs energy of individual phases. Therefore, the Gibbs energy functions for each phase in the binaries were defined in the binary databases. The Ca-Sr system was modeled by using random solution model. In modeling of the Al-Ca system, both random solution and associate models were applied to liquid phase. It was also demonstrated for the Al-Ca that the first-principles calculations provide reliable enthalpies of formation for stoichiometric compounds. The constructed quaternary database were used to calculate the liquidus projections of the ternary Mg-Al-Ca, Mg-Al-Sr, Mg-Ca-Sr and Al-Ca-Sr systems. Their primary crystallization fields and invariant reaction points were determined. Two Mg-based Mg-Al-Ca alloys were studied experimentally. The equilibrium phases in the alloys were determined after heat treatment. The present experimental results as well as the literature data were compared with the present thermodynamic calculations. The database was also utilized to understand the microstructures and phase relationships of the two quaternary alloys. Scheil simulations and equilibrium calculations were performed for the solidification process and compared with experimental observations.

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

    Science.gov (United States)

    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.

  5. Features of solid solutions composition in magnesium with yttrium alloys

    International Nuclear Information System (INIS)

    Drits, M.E.; Rokhlin, L.L.; Tarytina, I.E.

    1983-01-01

    Additional data on features of yttrium solid solutions composition in magnesium in the course of their decomposition investigation in the case of aging are obtianed. The investigation has been carried out on the base of a binary magnesium-yttrium alloy the composition of which has been close to maximum solubility (at eutectic temperature) and magnesium-yttrium alloys additionally doped with zinc. It is shown that higher yttrium solubility in solid magnesium than it has been expected, issueing from the difference in atomic radii of these metals indicates electron yttrium-magnesium atoms interaction. In oversaturated magnesium-yttrium solid solutions at earlier decomposition stages Mg 3 Cd type ordering is observed. At aging temperatures up to 250 deg C and long exposures corresponding to highest strengthening in oversaturated magnesium yttrium solid solutions a rhombic crystal lattice phase with three symmetric orientations is formed

  6. Investigation of Apple Scum and Its Modification with Magnesium Chloride and Hydrogen Peroxide for Removal of Toxic Hexavalent Chromium from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    M. Noori Sepehr

    2014-12-01

    Full Text Available Introduction: Chromium is one of the heavy metals present in effluents produced from industrial activities and exists in the trivalent and hexavalent state. It is mentioned that hexavalent chromium has is more hazardous due to its carcinogenic properties. Due to its hazard, Cr(VI must be removed from wastewaters prior discharge into the environment. For this reason, the present aimed for removal of hexavalent chromium by Apple Scum and its modification with magnesium chloride and hydrogen peroxide. Material and Methods: Apple Scum was obtained from Galin Plan as waste materials. The Apple Scum was modified with 2M MgCl2 and 30% H2O2. Several experimental parameters such as solution pH (1-9, contact time (1-100 min, solution temperature (20-60oC, adsorbent dosage (2-10 g/L and initial chromium concentration (10-100 mg/L was investigated. All experiments were done in batch system. Results: The results of present work reveals that chromium removal efficiency was increased with increase in adsorbent dosage, contact time and initial chromium concentration, while decreased for increase in solution pH and temperature. Higher removal efficiency was observed at pH 1, 100 min contact time, 100 mg/L chromium concentration and 20oC temperature. At this optimal condition up to 90% of chromium was removed. In addition, the modification of Apple Scum leads to increase in chromium removal efficiency up to 98% for MgCl2 modified adsorbent and up to 95% forH2O2 modified one. Conclusion: The results of present work well demonstrate the waste Apple Scum for removal of hexavalent chromium and its sorption capacity will be improved in the case of modification with H2O2 and MgCl2.

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

    DEFF Research Database (Denmark)

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

    2004-01-01

    temperatures. Apparent activation energies were calculated from Arrhenius plots revealing values of ca. 300 and 250 kJ/mol for the dehydrogenationof pure and nickel-doped magnesium hydride, respectively, in accord with EA= 270 kJ/mol measured by thermal desorption spectroscopy for these non-activated materials...

  8. Magnesium motorcycle applications

    International Nuclear Information System (INIS)

    Jianyong Cao; Zonghe Zhang; Dongxia Xiang; Jun Wang

    2005-01-01

    Magnesium, the lightest engineering structural metal, has been comprehensively used in castings of aviation and aerospace, communication and transportation, and IT components. This paper introduced the history, advantages and difficulties of magnesium castings for motorcycle application as well as its application state in China. It also indicated the production situation of magnesium motorcycle components in CQMST and difficulties need to overcome for further development. (orig.)

  9. Investigating the Spectral Dependence of Biomass Burning Aerosol Optical Properties

    Science.gov (United States)

    Odwuor, A.; Corr, C.; Pusede, S.

    2016-12-01

    Aerosol optical properties, such as light absorption and scattering, are important for understanding how aerosols affect the global radiation budget and for comparison with data gathered from remote sensing. It has been established that the optical properties of aerosols are wavelength dependent, although some remote sensing measurements do not consider this. Airborne measurements of these optical properties were used to calculate the absorption Angstrom exponent, a parameter that characterizes the wavelength dependence of light absorption by aerosols, and single scattering albedo, which measures the relative magnitude of light scattering to total extinction (scattering and absorption combined). Aerosols produced by biomass burning in Saskatchewan, Canada in July 2008 and a forest fire in Southern California, U.S. in June 2016 were included in this analysis. These wildfires were sampled by the NASA DC-8 aircraft during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) and NASA Student Airborne Research Program (SARP) missions, respectively. Aerosol absorption was measured using a particle soot photometer (PSAP) at 470, 532 and 660 nm. Scattering was measured using a 3-wavelength (450, 550 and 700 nm) nephelometer. Absorption Angstrom exponents were calculated at 470 and 660 nm and single scattering albedos were calculated at 450 and 550 nm. Results of this study indicate that disregarding the wavelength dependence of organic aerosol can understate the positive radiative forcing (warming) associated with aerosol absorption.

  10. Magnesium in pregnancy.

    Science.gov (United States)

    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.

  11. Radioactive 210Po in magnesium supplements

    International Nuclear Information System (INIS)

    Struminska-Parulska, Dagmara Ida

    2016-01-01

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

  12. Radioactive {sup 210}Po in magnesium supplements

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-01

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

  13. Effects of magnesium supplementation on electrophysiological remodeling of cardiac myocytes in L-NAME induced hypertensive rats.

    Science.gov (United States)

    Ozturk, Nihal; Olgar, Yusuf; Aslan, Mutay; Ozdemir, Semir

    2016-08-01

    Hypertension is one of the major risk factors of cardiac hypertrophy and magnesium deficiency is suggested to be a contributing factor in the progression of this complication. In this study, we aimed to investigate the relationship between intracellular free Mg(2+) levels and electrophysiological changes developed in the myocardium of L-NAME induced hypertensive rats. Hypertension was induced by administration of 40 mg/kg of L-NAME for 6 weeks, while magnesium treated rats fed with a diet supplemented with 1 g/kg of MgO for the same period. L-NAME administration for 6 weeks elicited a significant increase in blood pressure which was corrected with MgO treatment; thereby cardiac hypertrophy developing secondary to hypertension was prevented. Cytosolic free magnesium levels of ventricular myocytes were significantly decreased with hypertension and magnesium administration restored these changes. Hypertension significantly decreased the fractional shortening with slowing of shortening kinetics in left ventricular myocytes whereas magnesium treatment was capable of restoring hypertension-induced contractile dysfunction. Long-term magnesium treatment significantly restored the hypertension-induced prolongation in action potentials of ventricular myocytes and suppressed Ito and Iss currents. In contrast, hypertension dependent decrement in intracellular Mg(2+) level did not cause a significant change in L-type Ca(2+) currents, SR Ca(2+) content and NCX activity. Nevertheless, hypertension mediated increase in superoxide anion, hydrogen peroxide and protein oxidation mitigated with magnesium treatment. In conclusion, magnesium administration improves mechanical abnormalities observed in hypertensive rat ventricular myocytes due to reduced oxidative stress. It is likely that, changes in intracellular magnesium balance may contribute to the pathophysiology of chronic heart diseases.

  14. Temperature-dependent magnetic EXAFS investigation of Gd

    CERN Document Server

    Wende, H; Poulopoulos, P N; Rogalev, A; Goulon, J; Schlagel, D L; Lograsso, T A; Baberschke, K

    2001-01-01

    Magnetic EXAFS (MEXAFS) is the helicity-dependent counterpart of the well-established EXAFS technique. By means of MEXAFS it is possible not only to analyze the local magnetic structure but also to learn about magnetic fluctuations. Here we present the MEXAFS of a Gd single crystal at the L sub 3 sub , sub 2 -edges in the temperature range of 10-250 K. For the first time MEXAFS was probed over a large range in reduced temperature of 0.04<=T/T sub C<=0.85 with T sub C =293 K. We show that the vibrational damping described by means of a Debye temperature of theta sub D =160 K must be taken into account for the spin-dependent MEXAFS before analyzing magnetic fluctuations. For a detailed analysis of the MEXAFS and the EXAFS, the experimental data are compared to ab initio calculations. This enables us to separate the individual single- from the multiple-scattering contributions. The MEXAFS data have been recorded at the ID 12A beamline of the European Synchrotron Radiation Facility (ESRF). To ensure that th...

  15. Extracellular Calcium and Magnesium

    African Journals Online (AJOL)

    ABSTRACT. The cause of preeclampsia remains unknown and calcium and magnesium supplement are being suggested as means of prevention. The objective of this study was to assess magnesium and calcium in the plasma and cerebrospinal fluid of Nigerian women with preedamp sia and eclampsia. Setting was ...

  16. Magnesium in subarachnoid hemorrhage

    NARCIS (Netherlands)

    Bergh, W.M. (Walter Marcel) van den

    2004-01-01

    The main objective of this thesis was to determine the role of serum magnesium in the pathophysiology after subarachnoid hemorrhage (SAH) and to assess the effect of magnesium treatment in reducing cerebral ischemia in experimental SAH and in improving clinical outcome in patients with

  17. Solubilities of magnesium sulfite

    Czech Academy of Sciences Publication Activity Database

    Nývlt, Jaroslav

    2001-01-01

    Roč. 66, č. 2 (2001), s. 509-512 ISSN 1418-2874 Institutional research plan: CEZ:AV0Z4032918 Keywords : magnesium sulfate * magnesium sulfite * metastable solid Subject RIV: CA - Inorganic Chemistry Impact factor: 0.545, year: 2001

  18. Microscopic Investigation of Reversible Nanoscale Surface Size Dependent Protein Conjugation

    Directory of Open Access Journals (Sweden)

    Michael A. Carpenter

    2009-05-01

    Full Text Available Aβ1-40 coated 20 nm gold colloidal nanoparticles exhibit a reversible color change as pH is externally altered between pH 4 and 10. This reversible process may contain important information on the initial reversible step reported for the fibrillogenesis of Aβ (a hallmark of Alzheimer’s disease. We examined this reversible color change by microscopic investigations. AFM images on graphite surfaces revealed the morphology of Aβ aggregates with gold colloids. TEM images clearly demonstrate the correspondence between spectroscopic features and conformational changes of the gold colloid.

  19. Investigation of the Microstructure Evolution and Deformation Mechanisms of a Mg-Zn-Zr-RE Twin-Roll-Cast Magnesium Sheet by In-Situ Experimental Techniques

    Czech Academy of Sciences Publication Activity Database

    Máthis, K.; Horváth, Klaudia; Farkas, Gergely; Choe, H.; Shin, K. S.; Vinogradov, A.

    2018-01-01

    Roč. 11, č. 2 (2018), č. článku 200. ISSN 1996-1944 R&D Projects: GA ČR GB14-36566G; GA MŠk EF16_013/0001794 Institutional support: RVO:61389005 Keywords : magnesium * twin roll casting * neutron diffraction * acoustic emission * twinning * yield strength Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis Impact factor: 2.654, year: 2016

  20. Effect of sintering conditions on the microstructural and mechanical characteristics of porous magnesium materials prepared by powder metallurgy.

    Science.gov (United States)

    Čapek, Jaroslav; Vojtěch, Dalibor

    2014-02-01

    There has recently been an increased demand for porous magnesium materials in many applications, especially in the medical field. Powder metallurgy appears to be a promising approach for the preparation of such materials. Many works have dealt with the preparation of porous magnesium; however, the effect of sintering conditions on material properties has rarely been investigated. In this work, we investigated porous magnesium samples that were prepared by powder metallurgy using ammonium bicarbonate spacer particles. The effects of the purity of the argon atmosphere and sintering time on the microstructure (SEM, EDX and XRD) and mechanical behaviour (universal loading machine and Vickers hardness tester) of porous magnesium were studied. The porosities of the prepared samples ranged from 24 to 29 vol.% depending on the sintering conditions. The purity of atmosphere played a significant role when the sintering time exceeded 6h. Under a gettered argon atmosphere, a prolonged sintering time enhanced diffusion connections between magnesium particles and improved the mechanical properties of the samples, whereas under a technical argon atmosphere, oxidation at the particle surfaces caused deterioration in the mechanical properties of the samples. These results suggest that a refined atmosphere is required to improve the mechanical properties of porous magnesium. © 2013.

  1. Urinary and plasma magnesium and risk of ischemic heart disease.

    Science.gov (United States)

    Joosten, Michel M; Gansevoort, Ron T; Mukamal, Kenneth J; van der Harst, Pim; Geleijnse, Johanna M; Feskens, Edith J M; Navis, Gerjan; Bakker, Stephan J L

    2013-06-01

    Previous studies on dietary magnesium and risk of ischemic heart disease (IHD) have yielded inconsistent results, in part because of a lack of direct measures of actual magnesium uptake. Urinary excretion of magnesium, an indicator of dietary magnesium uptake, might provide more consistent results. The objective was to investigate whether urinary magnesium excretion and plasma magnesium are associated with IHD risk. We examined 7664 adult participants free of known cardiovascular disease in the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study-a prospective population-based cohort study. Urinary magnesium excretion was measured in 2 baseline 24-h urine collections. Mean ± SD urinary magnesium excretion was 4.24 ± 1.65 mmol/24 h for men and 3.54 ± 1.40 mmol/24 h for women. During a median follow-up of 10.5 y (IQR: 9.9-10.8 y), 462 fatal and nonfatal IHD events occurred. After multivariable adjustment, urinary magnesium excretion had a nonlinear relation with IHD risk (P-curvature = 0.01). The lowest sex-specific quintile (men: magnesium excretion. A similar increase in risk of the lowest quintile was observed for mortality related to IHD (HR: 1.70; 95% CI: 1.10, 2.61). No associations were observed between circulating magnesium and risk of IHD. Low urinary magnesium excretion was independently associated with a higher risk of IHD incidence. An increased dietary intake of magnesium, particularly in those with the lowest urinary magnesium, could reduce the risk of IHD.

  2. Modeling Adsorption Kinetics of Magnesium and Phosphate Ions on Goethite by Empirical Equations

    Directory of Open Access Journals (Sweden)

    Malihe Talebi Atouei

    2017-06-01

    Full Text Available Introduction: Natural environments, including soils and sediments, are open and complex systems in which physico-chemical reactions are in semi equilibrium state. In these systems, bioavailability of plant nutrients, like phosphate, is influenced by environmental conditions and concentrations of other ions such as calcium and magnesium. Magnesium is a dominant cation in irrigation water and in the soil solution of calcareous soils. Recent evidences show relative increase in the concentration of magnesium in irrigation water. Because of the importance of chemical kinetics in controlling concentrations of these ions in the soil solution and for understanding their effects of adsorption kinetics of magnesium and phosphate ions, in this research, adsorption kinetics of these two ions on goethite is investigated as function of time and pH in single ion and binary ion systems. The experimental data are described by using the adsorption kinetics equations. These data are of the great importance in better understanding adsorption interactions and ion adsorption mechanism.With respect to the importance of these interactions from both economical and environmental point of view, in this research, the kinetics and thermodynamics of phosphate and Mg2adsorption interactions were investigated as function of pH on soil model mineral goethite in both single and binary ion systems. Materials and Methods: Kinetics experiments were performed in the presence of 0.2 mM magnesium and 0.4 mM phosphate in 0.1 M NaCl background solution and 3 g L-1 goethite concentration as function of pH and time (1, 5, 14, 24, 48. 72 and 168 h in single ion and binary ion systems. After reaction time, the suspensions were centrifuged and a sample of supernatant was taken for measuring ions equilibrium concentrations.Phosphate concentration was measured calorimetrically with the ammonium molybdate blue method by spectrophotometer (Jenway-6505 UV/Vis. Magnesium concentration was

  3. Experimental investigations of a chimney-dependent solar crop dryer

    Energy Technology Data Exchange (ETDEWEB)

    Afriyie, J.K.; Nazha, M.A.A.; Rajakaruna, H. [School of Engineering and Technology, De Montfort University, Queens Building, The Gateway, Leicester LE1 9BH (United Kingdom); Forson, F.K. [Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana)

    2009-01-15

    An experimental investigation into the performance of a solar crop dryer with solar chimney and no air preheating is described. Tests were first performed on the cabinet dryer, using a normal chimney. The trials were repeated with a solar chimney. Still with the solar chimney, further trials were carried out with the roof of the drying chamber inclined further to form a tent dryer. The described tests include no-load tests for airflow rate measurements and drying tests, with cassava as the crop. Air velocities, temperatures, ambient relative humidity and the drop in crop moisture contents at different stages of the drying process are also presented. The effects of the various configurations described above on the drying process are deduced and discussed while comparing the experimental results with one another. In addition, the performance of the dryer in relation to other natural convection dryers is discussed. The results show that the solar chimney can increase the airflow rate of a direct-mode dryer especially when it is well designed with the appropriate angle of drying-chamber roof. However, the increase in flow rate only increases the drying rate when the relative humidity (RH) of the ambient air is below a certain mark (60% for cassava). (author)

  4. LOST FOAM CASTING OF MAGNESIUM ALLOYS

    Energy Technology Data Exchange (ETDEWEB)

    Han, Qingyou [ORNL; Dinwiddie, Ralph Barton [ORNL; Sklad, Philip S [ORNL; Currie, Kenneth [Tennessee Technological University; Abdelrahman, Mohamed [Tennessee Technological University; Vondra, Fred [Tennessee Technological University; Walford, Graham [Walford Technologies; Nolan, Dennis J [Foseco-Morval

    2007-01-01

    The lost foam casting process has been successfully used for making aluminum and cast iron thin walled castings of complex geometries. Little work has been carried out on cast magnesium alloys using the lost foam process. The article describes the research activities at Oak Ridge National Laboratory and Tennessee Technological University on lost foam casting of magnesium alloys. The work was focused on castings of simple geometries such as plate castings and window castings. The plate castings were designed to investigate the mold filling characteristics of magnesium and aluminum alloys using an infrared camera. The pate castings were then characterized for porosity distribution. The window castings were made to test the castability of the alloys under lost foam conditions. Significant differences between lost foam aluminum casting and lost foam magnesium casting have been observed.

  5. [Magnesium level in human organism during 105-day isolation].

    Science.gov (United States)

    Piruzian, L A; Protasova, O V; Maksimova, I A; Morukov, B V; Protasov, S V; Ushakov, I B

    2012-01-01

    Total and ionized magnesium in blood serum and in daily urine were determined before (baseline values) and on days 30, 60 and 105 of the experiment with 105-d isolation and confinement (Mars-105)/ Magnesium in hair was investigated before (baseline values) and on day-105 of the experiment. The investigations were performed using atomic emission spectrometry with inductively coupled argon plasma. Changes in magnesium were most significant over the initial 30 days in the experiment. Reduction of serum magnesium was accounted for by the fall in the ionized fraction. In organism magnesium is controlled by the ion-regulatory function of the kidney and varies with individuals. Levels of ionized magnesium in blood serum and excreted with daily urine can serve as indicators of stress resistivity .

  6. Magnesium for Crashworthy Components

    Science.gov (United States)

    Abbott, T.; Easton, M.; Schmidt, R.

    Most applications of magnesium in automobiles are for nonstructural components. However, the light weight properties of magnesium make it attractive in structural applications where energy absorption in a crash is critical. Because most deformation in a crash occurs as bending rather than simple tension or compression, the advantages of magnesium are greater than anticipated simply from tensile strength to weight ratios. The increased thickness possible with magnesium strongly influences bending behavior and theoretical calculations suggest almost an order of magnitude greater energy absorption with magnesium compared to the same weight of steel. The strain rate sensitivity of steel is of concern for energy absorption. Mild steels exhibit a distinct yield point which increases with strain rate. At strain rates typical of vehicle impact, this can result in strain localization and poor energy absorption. Magnesium alloys with relatively low aluminum contents exhibit strain rate sensitivity, however, this is manifest as an increase in work hardening and tensile / yield ratio. This behavior suggests that the performance of magnesium alloys in terms of energy absorption actually improves at high strain rates.

  7. Magnesium excretion and hypomagnesemia in pediatric renal transplant recipients.

    Science.gov (United States)

    Uslu Gökceoğlu, Arife; Comak, Elif; Dogan, Cagla Serpil; Koyun, Mustafa; Akbas, Halide; Akman, Sema

    2014-08-01

    We investigated magnesium excretion and rate of hypomagnesemia in pediatric renal transplant recipients. The medical records of 114 pediatric renal transplant recipients were retrospectively evaluated. After exclusion of 23 patients, 91 patients were included in the study. We recorded serum magnesium levels at the time of measurement of urine magnesium wasting. Mean serum magnesium levels were 1.73 ± 0.22 mg/dL and 38 of the patients (41%) had hypomagnesemia. There was a negative correlation between serum magnesium levels and estimated glomerular filtration rate and serum tacrolimus trough level (r=-0.215, p=0.040 and r=-0.409, p=0.000, respectively). Also, there was a statistically significant positive correlation between serum magnesium levels and transplantation duration (r=0.249, p=0.017). Mean fractional magnesium excretion was 5.9 ± 3.7% and 59 patients (65%) had high magnesium excretion. There was a significant negative correlation between fractional magnesium excretion and estimated glomerular filtration rate (r=-0.432, p=0.001). There was a significant positive correlation between fractional magnesium excretion and serum creatinine (r=0.379 p=0.003). Patients with higher tacrolimus trough blood levels, lower glomerular filtration rate and at early posttransplant period had risk of hypomagnesemia.

  8. Method for production of magnesium

    Science.gov (United States)

    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.

  9. Discussion about magnesium phosphating

    OpenAIRE

    Pokorny, P.; Tej, P.; Szelag, P.

    2016-01-01

    The paper describes results from recently published research focused on production of non-conventional magnesium phosphate Mg3(PO4)2・4H2O – bobierrite, or MgHPO4・3H2O – newberyite) coating for both magnesium alloys and/or mild steel. This new kind of coating is categorized in the context of current state of phosphating technology and its potential advantages and crystal structure is discussed. At the same time, the suitable comparison techniques for magnesium phosphate coating and convention...

  10. Discussion about magnesium phosphating

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2016-07-01

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

  11. Castability of Magnesium Alloys

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2013-12-01

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

  13. The Importance of Magnesium in the Human Body: A Systematic Literature Review

    DEFF Research Database (Denmark)

    Glasdam, Sidsel-Marie; Glasdam, Stinne; Peters, Günther H.J.

    2016-01-01

    Magnesium, the second and fourth most abundant cation in the intracellular compartment and whole body, respectively, is of great physiologic importance. Magnesium exists as bound and free ionized forms depending on temperature, pH, ionic strength, and competing ions. Free magnesium participates...

  14. Struvite precipitation from urine with electrochemical magnesium dosage.

    Science.gov (United States)

    Hug, Alexandra; Udert, Kai M

    2013-01-01

    When magnesium is added to source-separated urine, struvite (MgNH(4)PO(4)·6H(2)O) precipitates and phosphorus can be recovered. Up to now, magnesium salts have been used as the main source of magnesium. Struvite precipitation with these salts works well but is challenging in decentralized reactors, where high automation of the dosage and small reactor sizes are required. In this study, we investigated a novel approach for magnesium dosage: magnesium was electrochemically dissolved from a sacrificial magnesium electrode. We demonstrated that this process is technically simple and economically feasible and thus interesting for decentralized reactors. Linear voltammetry and batch experiments at different anode potentials revealed that the anode potential must be higher than -0.9 V vs. NHE (normal hydrogen electrode) to overcome the strong passivation of the anode. An anode potential of -0.6 V vs. NHE seemed to be suitable for active magnesium dissolution. For 13 subsequent cycles at this potential, we achieved an average phosphate removal rate of 3.7 mg P cm(-2) h(-1), a current density of 5.5 mA cm(-2) and a current efficiency of 118%. Some magnesium carbonate (nesquehonite) accumulated on the anode surface; as a consequence, the current density decreased slightly, but the current efficiency was not affected. The energy consumption for these experiments was 1.7 W h g P(-1). A cost comparison showed that sacrificial magnesium electrodes are competitive with easily soluble magnesium salts such as MgCl(2) and MgSO(4), but are more expensive than dosing with MgO. Energy costs for the electrochemical process were insignificant. Dosing magnesium electrochemically could thus be a worthwhile alternative to dosing magnesium salts. Due to the simple reactor and handling of magnesium, this may well be a particularly interesting approach for decentralized urine treatment. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  16. The Circulating Concentration and 24-h Urine Excretion of Magnesium Dose- and Time-Dependently Respond to Oral Magnesium Supplementation in a Meta-Analysis of Randomized Controlled Trials.

    Science.gov (United States)

    Zhang, Xi; Del Gobbo, Liana C; Hruby, Adela; Rosanoff, Andrea; He, Ka; Dai, Qi; Costello, Rebecca B; Zhang, Wen; Song, Yiqing

    2016-03-01

    Accurate determination of Mg status is important for improving nutritional assessment and clinical risk stratification. We aimed to quantify the overall responsiveness of Mg biomarkers to oral Mg supplementation among adults without severe diseases and their dose- and time responses using available data from randomized controlled trials (RCTs). We identified 48 Mg supplementation trials (n = 2131) through searches of MEDLINE and the Cochrane Library up to November 2014. Random-effects meta-analysis was used to estimate weighted mean differences of biomarker concentrations between intervention and placebo groups. Restricted cubic splines were used to determine the dose- and time responses of Mg biomarkers to supplementation. Among the 35 biomarkers assessed, serum, plasma, and urine Mg were most commonly measured. Elemental Mg supplementation doses ranged from 197 to 994 mg/d. Trials ranged from 3 wk to 5 y (median: 12 wk). Mg supplementation significantly elevated circulating Mg by 0.04 mmol/L (95% CI: 0.02, 0.06) and 24-h urine Mg excretion by 1.52 mmol/24 h (95% CI: 1.20, 1.83) as compared to placebo. Circulating Mg concentrations and 24-h urine Mg excretion responded to Mg supplementation in a dose- and time-dependent manner, gradually reaching a steady state at doses of 300 mg/d and 400 mg/d, or after ~20 wk and 40 wk, respectively (all P-nonlinearity ≤ 0.001). The higher the circulating Mg concentration at baseline, the lower the responsiveness of circulating Mg to supplementation, and the higher the urinary excretion (all P-linearity urine calcium were significantly more elevated by Mg supplementation than by placebo (all P-values urine Mg excretion to oral Mg supplementation. © 2016 American Society for Nutrition.

  17. Magnesium blood test

    Science.gov (United States)

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

  18. [Magnesium and bronchopulmonary dysplasia].

    Science.gov (United States)

    Fridman, Elena; Linder, Nehama

    2013-03-01

    Bronchopulmonary dysplasia (BPD) is a chronic lung disease that occurs in premature infants who have needed mechanical ventilation and oxygen therapy. BPD is defined as the presence of persistent respiratory symptoms, the need for supplemental oxygen to treat hypoxemia, and an abnormal chest radiograph at 36 weeks gestational age. Proinflammatory cytokines and altered angiogenic gene signaling impair prenatal and postnatal lung growth, resulting in BPD. Postnatal hyperoxia exposure further increases the production of cytotoxic free radicals, which cause lung injury and increase the levels of proinflammatory cytokines. Magnesium is the fourth most abundant metal in the body. It is commonly used for the treatment of preeclamsia, as well as for premature labor alleviation. Magnesium's role in BPD development is not clear. A significant association between high magnesium levels at birth and respiratory distress syndrome (RDS), pulmonary interstitial emphysema in the extremely low birth weight, respiratory failure, and later development BPD was found. Conversely, low magnesium intake is associated with lower lung functions, and hypomagnesemia was found in 16% of patients with acute pulmonary diseases. Magnesium is used for the treatment of asthmatic attacks. Magnesium deficiency in pregnant women is frequently seen due to low intake. Hypomagnesemia was also found among preterm neonates and respiratory distress syndrome (RDS). Experimental hypomagnesemia evokes an inflammatory response, and oxidative damage of tissues. These were accompanied by changes in gene expression mostly involved in regulation of cell cycle, apoptosis and remodeling, processes associated with BPD. It is rational to believe that hypomagnesemia can contribute to BPD pathogenesis.

  19. Solidification of metallic aluminum on magnesium phosphate cements

    International Nuclear Information System (INIS)

    Lahalle, Hugo

    2016-01-01

    This work deals with the stabilization/solidification of radioactive waste using cement. More particularly, it aims at assessing the chemical compatibility between metallic aluminum and mortars based on magnesium phosphate cement. The physical and chemical processes leading to setting and hardening of the cement are first investigated. X-ray diffraction (XRD), thermogravimetry (TGA) and nuclear magnetic resonance spectroscopy ( 31 P and 11 B MAS-NMR) are first used to characterize the solid phases formed during hydration, while inductively coupled plasma atomic emission spectroscopy analysis (ICP-AES), electrical conductometry and pH measurements provide information on the pore solution composition. Then, the corrosion of metallic aluminum in magnesium phosphate mortars is studied by monitoring the equilibrium potential and by electrochemical impedance spectroscopy (EIS). Magnesium phosphate cement is prepared from a mix of magnesium oxide (MgO) and potassium dihydrogen orthophosphate (KH 2 PO 4 ). In the presence of water, hydration occurs according to a dissolution - precipitation process. The main hydrate is K-struvite (MgKPO 4 .6H 2 O). Its precipitation is preceded by that of two transient phases: phosphorrosslerite (MgHPO 4 .7H 2 O) and Mg 2 KH(PO 4 ) 2 .15H 2 O. Boric acid retards cement hydration by delaying the formation of cement hydrates. Two processes may be involved in this retardation: the initial precipitation of amorphous or poorly crystallized minerals containing boron and phosphorus atoms, and/or the stabilization of cations (Mg 2+ , K + ) in solution. As compared with a Portland cement-based matrix, corrosion of aluminum is strongly limited in magnesium phosphate mortar. The pore solution pH is close to neutrality and falls within the passivation domain of aluminum. Corrosion depends on several parameters: it is promoted by a water-to-cement ratio (w/c) significantly higher than the chemical water demand of cement (w/c = 0.51), and by the

  20. Electrodeposition of magnesium and magnesium/aluminum alloys

    Science.gov (United States)

    Mayer, A.

    1988-01-21

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

  1. Validation of magnesium sensitive genes as a biomarkers for the intracellular magnesium status of patients with diabetes mellitus

    OpenAIRE

    Kurth, Katharina

    2013-01-01

    The expression of magnesium sensitive genes as a function of the extracellular magnesium concentration was investigated in a cell culture experiment. At low magnesium condition, cells of JVM-13 and Jurkat lines exhibited high expression of SLC41A1, CNNM2, TRPM7, NIPA1 and N33 genes. It was hypothesized, that with knowledge of the expression rate of these genes, one gains insight about the intracellular magnesium status. The capability of the CNNM2 gene as a biomarker was tested in a screening...

  2. Grain refinement of AZ31 magnesium alloy by electromagnetic ...

    Indian Academy of Sciences (India)

    The effects of electromagnetic stirring and Al4C3 grain refiner on the grain refinement of semicontinuously cast AZ31 magnesium alloy were discussed in this investigation. The results indicate that electromagnetic stirring has an effective refining effect on the grain size of AZ31 magnesium alloy under the effect of Al4C3 ...

  3. Effects of magnesium sulfate on the acquisition and reinstatement of ...

    African Journals Online (AJOL)

    In the current study, the effects of magnesium sulfate on the acquisition and reinstatement of morphine-induced conditioned place preference (CPP) in an animal model were investigated. The acquisition and extinction and reinstatement phases induced using morphine 40 and 10mg/kg. Magnesium sulfate 300 and 600 ...

  4. Gastroprotective Effect of Magnesium on Indomethacin-induced ...

    African Journals Online (AJOL)

    Magnesium is reported to reduce acid secretion and possess hypoglycemic properties. However, information about its gastroprotective ability is unknown. The gastroprotective effect of magnesium on indomethacin-induced gastric ulceration in normal and alloxan-induced diabetic rats was investigated. Male rats were ...

  5. Grain refinement of AZ31 magnesium alloy by electromagnetic ...

    Indian Academy of Sciences (India)

    Abstract. The effects of electromagnetic stirring and Al4C3 grain refiner on the grain refinement of semi- continuously cast AZ31 magnesium alloy were discussed in this investigation. The results indicate that electromag- netic stirring has an effective refining effect on the grain size of AZ31 magnesium alloy under the effect of ...

  6. 76 FR 11813 - Magnesium From China and Russia

    Science.gov (United States)

    2011-03-03

    ... COMMISSION Magnesium From China and Russia Determinations On the basis of the record \\1\\ developed in the... China and Russia: Investigation Nos.731-TA- 1071-1072 (Review). By order of the Commission. Issued... antidumping duty order on magnesium from China would be likely to lead to continuation or recurrence of...

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

    Directory of Open Access Journals (Sweden)

    W.H. Ma

    2015-03-01

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

  8. The initial oxidation of magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Kurth, M.

    2004-07-01

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

  9. Spider silk as a template for obtaining magnesium oxide and magnesium hydroxide fibers

    Directory of Open Access Journals (Sweden)

    Dmitrović Svetlana

    2018-01-01

    Full Text Available Spider silk fibers, collected from Pholcus Phalangioides spider were used as a template for obtaining magnesium oxide (MgO, periclase as well as magnesium hydroxide (Mg(OH2, brucite fibers. Magnesium oxide fibers were obtained in a simple manner by heat induced decomposition of magnesium salt (MgCl2 in the presence of the spider silk fibers, while magnesium hydroxide fibers were synthesized by hydration of MgO fibers at 50, 70 and 90 C, for 48 and 96 h. According to Scanning electron microscopy (SEM, dimensions of spider silk fibers determined the dimension of synthesized MgO fibers, while for Mg(OH2 fibers, the average diameter was increased with prolonging the hydration period. The surface of Mg(OH2 fibers was noticed to be covered with brucite in a form of plates. X-Ray diffraction (XRD analysis showed that MgO fibers were single-phased (the pure magnesium oxide fibers were obtained, while Mg(OH2 fibers were two- or single-phased brucite depending on incubation period, and/or incubation temperature. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 45012

  10. [Plasma ionized magnesium concentration following cardiopulmonary bypass].

    Science.gov (United States)

    Amaya, Fumimasa; Fukui, Michihiko; Tsuruta, Hiroshi; Kooguchi, Kunihiko; Shimosato, Goshun

    2002-06-01

    We performed a retrospective study to analyze plasma ionized magnesium concentration following cardiopulmonary bypass. Severe decrease of ionized magnesium concentration associated with frequent abnormal ECG sign was found in a patient with magnesium-free cardioplegia. Cardioplegia containing 16 mmol.l-1 of magnesium ion maintained ionized magnesium concentration within normal ranges without postoperative magnesium loading. Use of cardioplegia containing magnesium or adequate magnesium supplement is thought to be essential for patients receiving cardiopulmonary bypass.

  11. Effect of chronic stress and sleep deprivation on both flow-mediated dilation in the brachial artery and the intracellular magnesium level in humans.

    Science.gov (United States)

    Takase, Bonpei; Akima, Takashi; Uehata, Akimi; Ohsuzu, Fumitaka; Kurita, Akira

    2004-04-01

    Chronic mental and physical stress has been suggested to be a trigger for cardiovascular events. In addition, a reduction in levels of intracellular magnesium has been reported to cause vasoconstriction while enhancing platelet-dependent thrombosis. The purpose of this study was to investigate whether chronic stress affects endothelial function and intracellular magnesium levels in humans. Flow-mediated dilation (endothelium-dependent vasodilation) and sublingual nitroglycerin-induced dilation (0.3 mg, endothelium-independent vasodilation) were measured in the brachial artery in 30 healthy male college students, aged 22 +/- 1 years, using high-resolution ultrasound both before and immediately after a 4-week final term examination period. Erythrocyte magnesium concentration was measured simultaneously. All students had chronic sleep deprivation for 4 weeks, during which sleep lasted students were under great stress to pass the examination. This condition was considered to be chronic stress. Chronic stress decreased flow-mediated dilation and erythrocyte magnesium concentration (from 7.4 +/- 3.0 to 3.7 +/- 2.3%, p < 0.05; from 5.7 +/- 0.4 to 5.5 +/- 0.4 mg/ml, p < 0.05, respectively). The change in flow-mediated dilation correlated significantly with that of the erythrocyte magnesium concentration (r = 0.43, p < 0.05), but not with nitroglycerin-induced dilation. Chronic stress was found to attenuate endothelial function, which may also be associated with a reduction in the intracellular magnesium level in humans.

  12. Magnesium Borohydride: From Hydrogen Storage to Magnesium Battery

    OpenAIRE

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

    2012-01-01

    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.

  13. 21 CFR 184.1434 - Magnesium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium phosphate. 184.1434 Section 184.1434 Food... Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic (MgHPO4·3H2O...

  14. Aluminum Hydroxide and Magnesium Hydroxide

    Science.gov (United States)

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

  15. Hetero- and Homoleptic Magnesium Triazenides

    Directory of Open Access Journals (Sweden)

    Denis Vinduš

    2017-05-01

    Full Text Available Using monoanionic triazenide ligands derived from biphenyl and m-terphenyl substituted triazenes Dmp(TphN3H (1a, (Me4Ter2N3H (1b or Dmp(MphN3H (1c (Dmp = 2,6-Mes2C6H3 with Mes = 2,4,6-Me3C6H2; Me4Ter = 2,6-(3,5-Me2C6H32C6H3; Mph = 2-MesC6H4; Tph = 2-TripC6H4 with Trip = 2,4,6-i-Pr3C6H2, several magnesium triazenides were synthesized. Heteroleptic complexes [Mg(N3Ar2I(OEt2] (Ar2 = Dmp/Tph (2a, (Me4Ter2 (2b were obtained from metalation of the corresponding triazenes with di-n-butylmagnesium followed by reaction with iodine in diethyl ether as the solvent in high yields. Replacing diethyl ether by n-heptane afforded trinuclear compounds [Mg3(N3Ar22I4] (3a, 3b in low yields in which a central MgI2 fragment is coordinated by two iodomagnesium triazenide moieties. Two unsolvated homoleptic magnesium compounds [Mg(N3Ar22] (4b, 4c were obtained from di-n-butylmagnesium and triazenes 1b or 1c in a 1:2 ratio. Depending on the nature of the substituents, the magnesium center either shows the expected tetrahedral or a rather unusual square planar coordination.

  16. Magnesium for Hydrogen Storage

    DEFF Research Database (Denmark)

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

    1983-01-01

    A study of the hydrogenation characteristics of fine magnesium powder during repeated cycling has been performed using a high-pressure microbalance facility. No effect was found from the cycling regarding kinetics and storage capacity. The reaction rate of the absorption process was fast at tempe......A study of the hydrogenation characteristics of fine magnesium powder during repeated cycling has been performed using a high-pressure microbalance facility. No effect was found from the cycling regarding kinetics and storage capacity. The reaction rate of the absorption process was fast...

  17. Post traumatic tetanus and role magnesium sulphate

    International Nuclear Information System (INIS)

    Sikendr, R.I.; Samad, B.U.; Memon, M.I.

    2009-01-01

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

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

    International Nuclear Information System (INIS)

    Kim, Dong-Wook; Kim, Tae-Hee; Park, Hyun-Woo; Park, Dong-Wha

    2011-01-01

    Nanocrystalline magnesium nitride (Mg 3 N 2 ) powder was synthesized from bulk magnesium by thermal plasma at atmospheric pressure. Magnesium vapor was generated through heating the bulk magnesium by DC plasma jet and reacted with ammonia gas. Injecting position and flow rates of ammonia gas were controlled to investigate an ideal condition for Mg 3 N 2 synthesis. The synthesized Mg 3 N 2 was cooled and collected on the chamber wall. Characteristics of the synthesized powders for each experimental condition were analyzed by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and thermogravity analysis (TGA). In absence of NH 3 , magnesium metal powder was formed. The synthesis with NH 3 injection in low temperature region resulted in a formation of crystalline magnesium nitride with trigonal morphology, whereas the mixture of magnesium metal and amorphous Mg 3 N 2 was formed when NH 3 was injected in high temperature region. Also, vaporization process of magnesium was discussed.

  19. Investigation into the mechanisms of time dependent deformation of hard rocks.

    CSIR Research Space (South Africa)

    Drescher, K

    2002-02-01

    Full Text Available The testing undertaken for this dissertation is intended to help quantify the various time-dependant deformation processes around typical deep level hard rock tabular excavations. Three mechanisms were investigated and two different hard rock types...

  20. Investigating the Impact of Internet Dependency on Student-Teachers' Loneliness of Adiyaman University

    Science.gov (United States)

    Aytaç, Kürsat Yusuf

    2018-01-01

    This research was conducted to investigate the effect of internet dependency on student- teachers' loneliness of Admiyaman University. The study also examined the differences in internet dependency and loneliness among students and teachers of Adiyaman University of Turkey. The standard questionnaire of Jung (1996) was used to measure the internet…

  1. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    TECS

    ting. It is used in industrial floorings, ship decks, railway passenger coach floorings, hospital floors, ammunition factory floors, missile silos and underground armament factories and bunkers. Recently, concrete of high compres- sive and tensile strength prepared with magnesium oxy- chloride cement and recycled rubber ...

  2. Magnesium fluoride recovery method

    International Nuclear Information System (INIS)

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

    1989-01-01

    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

  3. Serum magnesium concentration in drug-addicted patients.

    Science.gov (United States)

    Karakiewicz, Beata; Kozielec, Tadeusz; Brodowski, Jacek; Chlubek, Dariusz; Noceń, Iwona; Starczewski, Andrzej; Brodowska, Agnieszka; Laszczyńska, Maria

    2007-03-01

    Drug addiction is a complex problem which leads to many somatic, psychic and social diseases. It is accompanied by the disturbed metabolism of various macro and micronutrients. The aim of this study was to assess serum magnesium concentration in drug-addicted patients and analyze whether Human Immunodeficiency Virus (HIV) infection and methadone treatment affect the level of serum magnesium in these patients. The examination was conducted in a group of 83 people - patients of Szczecin-Zdroje Psychiatric Hospital (Poland). They were 21 to 49 years old, and the mean age was 32 +/- 7 years. The control group consisted of 81 healthy individuals. Flame atomic-absorption spectrometry method was used to determine the magnesium concentration. The total serum magnesium concentration was calculated for the whole patient group, subgroups of women and men, a subgroup of people infected with HIV, and a subgroup receiving methadone substitution treatment. How magnesium behaves depending on age and addiction period, was checked. The mean concentration of magnesium in blood serum of the patients examined was 0.57 mmol/L, which was significantly lower than in the control group. In the subgroup of men it was 0.57 mmol/L, and in the subgroup of women - 0.55 mmol/L; the differences were not statistically significant. In the patient group nobody had the appropriate magnesium concentration in blood serum. No significant correlation was found between the magnesium concentration, age of the patients and addiction period. In the subgroup of seropositive people the mean concentration of magnesium was 0.55 mmol/L, and in the subgroup of non-infected patients - 0.58 mmol/L; the difference was not statistically significant. The mean concentration of magnesium in the subgroup treated with methadone was 0.59 mmol/L, and in the subgroup not involved in this type of therapy - 0.55 mmol/L; it was not a statistically significant difference.

  4. The forming process of magnesium alloy for Japanese home electric components

    Energy Technology Data Exchange (ETDEWEB)

    Takara, A. [Matsushita Electric Industrial Co., Kadoma, Osaka (Japan); Higashi, K. [Osaka Prefecture Univ., Sakai, Osaka (Japan)

    2005-07-01

    Magnesium alloys have replaced resins as a material for the components of electronic products such as cell phone and notebook personal computer mainly, because of their lightness and rigidity. Thin walls, a complicated shape, and high appearance quality are all needed in the external parts. Die-casting and injection molding are the main method of manufacturing magnesium alloy parts. The optimal cast conditions and mold design have been investigated in order that a few defects such as surface cracks and mold cavities in casting parts would be reduced. Instead of cast, plastic forming technologies such as warm drawing and hot forging have been developed to form thinner walls and less defects. Plastic formability of magnesium alloy in hot working is dependent on a grain size of material. The material with fine grains has advantage of being formed at high strain rate. The characteristics of forming processes of magnesium parts for Japanese home electric appliances are compared in the viewpoint of quality, cost, and productivity. (orig.)

  5. Optical Humidity Sensing Using Transparent Hybrid Film Composed of Cationic Magnesium Porphyrin and Clay Mineral.

    Science.gov (United States)

    Fujimura, Takuya; Shimada, Tetsuya; Sasai, Ryo; Takagi, Shinsuke

    2018-03-13

    A transparent hybrid film composed of cationic magnesium porphyrin and clay mineral was developed, and its chromic behavior depending on relative humidity (RH) was investigated. The hybrid film was obtained via intercalation of magnesium porphyrin into clay film; magnesium porphyrin was intercalated into the interlayer spaces of the clay mineral without aggregation. The absorption spectra of the hybrid film showed red shifts compared to the aqueous solution of magnesium porphyrin because of the π-conjugated system extension with coplanarization of the meso-substituted pyridinium group and porphyrin ring. The absorption maximum of the hybrid film was gradually shifted to a shorter wavelength, and the color of the hybrid film was changed with increasing RH. The X-ray diffraction measurement suggested that the basal space of clay was expanded with increasing RH, indicating that the interlayer space of clay was expanded by water adsorption, and the spectral shift was induced by the change in coplanarization degree between the porphyrin ring and meso-substituted pyridinium groups.

  6. Investigation of the dependency of wind turbine loads on the simulation time

    DEFF Research Database (Denmark)

    Tibaldi, Carlo; Henriksen, Lars Christian; Bak, Christian

    2014-01-01

    In this work the dependency of several wind turbine parameters with respect to the length of simulations used for their evaluation is investigated. The analysis is performed by computing the parameters with a different number of turbulent wind simulations, therefore simulation time, and repeating...... the computation with different turbulence realizations. The repetition of the computation is performed to identify the scatter of the parameters for a given number of turbulent seeds due to the different turbulence realization. The dependency on the simulation time of load variations due to changes...... in the collective pitch controller tuning is also investigated. Results show a significantly high dependency of the parameters and their variations on the turbulent wind realization. This dependency makes the use of turbulent wind simulation results not reliable for numerical optimization purposes....

  7. Protein phosphatase magnesium dependent 1A (PPM1A plays a role in the differentiation and survival processes of nerve cells.

    Directory of Open Access Journals (Sweden)

    Meytal Shohat

    Full Text Available The serine/threonine phosphatase type 2C (PPM1A has a broad range of substrates, and its role in regulating stress response is well established. We have investigated the involvement of PPM1A in the survival and differentiation processes of PC6-3 cells, a subclone of the PC12 cell line. This cell line can differentiate into neuron like cells upon exposure to nerve growth factor (NGF. Overexpression of PPM1A in naive PC6-3 cells caused cell cycle arrest at the G2/M phase followed by apoptosis. Interestingly, PPM1A overexpression did not affect fully differentiated cells. Using PPM1A overexpressing cells and PPM1A knockdown cells, we show that this phosphatase affects NGF signaling in PC6-3 cells and is engaged in neurite outgrowth. In addition, the ablation of PPM1A interferes with NGF-induced growth arrest during differentiation of PC6-3 cells.

  8. Low brain magnesium in migraine

    International Nuclear Information System (INIS)

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

    1989-01-01

    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. Serum magnesium and the risk of prediabetes: a population-based cohort study.

    Science.gov (United States)

    Kieboom, Brenda C T; Ligthart, Symen; Dehghan, Abbas; Kurstjens, Steef; de Baaij, Jeroen H F; Franco, Oscar H; Hofman, Albert; Zietse, Robert; Stricker, Bruno H; Hoorn, Ewout J

    2017-05-01

    Previous studies have found an association between serum magnesium and incident diabetes; however, this association may be due to reverse causation, whereby diabetes may induce urinary magnesium loss. In contrast, in prediabetes (defined as impaired fasting glucose), serum glucose levels are below the threshold for urinary magnesium wasting and, hence, unlikely to influence serum magnesium levels. Thus, to study the directionality of the association between serum magnesium levels and diabetes, we investigated its association with prediabetes. We also investigated whether magnesium-regulating genes influence diabetes risk through serum magnesium levels. Additionally, we quantified the effect of insulin resistance in the association between serum magnesium levels and diabetes risk. Within the population-based Rotterdam Study, we used Cox models, adjusted for age, sex, lifestyle factors, comorbidities, kidney function, serum levels of electrolytes and diuretic use, to study the association between serum magnesium and prediabetes/diabetes. In addition, we performed two mediation analyses: (1) to study if common genetic variation in eight magnesium-regulating genes influence diabetes risk through serum magnesium levels; and (2) to quantify the proportion of the effect of serum magnesium levels on diabetes that is mediated through insulin resistance (quantified by HOMA-IR). A total of 8555 participants (mean age, 64.7 years; median follow-up, 5.7 years) with normal glucose levels (mean ± SD: 5.46 ± 0.58 mmol/l) at baseline were included. A 0.1 mmol/l decrease in serum magnesium level was associated with an increase in diabetes risk (HR 1.18 [95% CI 1.04, 1.33]), confirming findings from previous studies. Of interest, a similar association was found between serum magnesium levels and prediabetes risk (HR 1.12 [95% CI 1.01, 1.25]). Genetic variation in CLDN19, CNNM2, FXYD2, SLC41A2, and TRPM6 significantly influenced diabetes risk (p magnesium levels. We

  10. The Corrosion of Magnesium and of the Magnesium Aluminum Alloys Containing Manganese

    Science.gov (United States)

    Boyer, J A

    1927-01-01

    The extensive use of magnesium and its alloys in aircraft has been seriously handicapped by the uncertainties surrounding their resistance to corrosion. This problem has been given intense study by the American Magnesium Corporation and at the request of the Subcommittee on Materials for Aircraft of the National Advisory Committee for Aeronautics this report was prepared on the corrosion of magnesium. The tentative conclusions drawn from the experimental facts of this investigation are as follows: the overvoltage of pure magnesium is quite high. On immersion in salt water the metal corrodes with the liberation of hydrogen until the film of corrosion product lowers the potential to a critical value. When the potential reaches this value it no longer exceeds the theoretical hydrogen potential plus the overvoltage of the metal. Rapid corrosion consequently ceases. When aluminum is added, especially when in large amounts, the overvoltage is decreased and hydrogen plates out at a much lower potential than with pure magnesium. The addition of small amount of manganese raises the overvoltage back to practically that of pure metal, and the film is again negative.

  11. Investigation of drop geometry at free-falling process depending on volume of dozing

    Directory of Open Access Journals (Sweden)

    Batischeva Ksenia A.

    2015-01-01

    Full Text Available Present work performs experimental investigation of the changes in the geometric shape of the drop in terms of its free-falling, depending on the conditions of drop formation on dispenser. It was found that volume and velocity of drop formation on dispenser are the factors affecting the geometric shape of the drop in terms of its free-falling.

  12. Strength and deformation behaviour of magnesium die casting alloys

    International Nuclear Information System (INIS)

    Regener, D.; Schick, E.; Wagner, I.; Heyse, H.

    1999-01-01

    Modern magnesium die casting alloys are used for the manufacturing of automotive parts due to their low density, fortunate mechanical and physical properties as well as good castability and machinability. However, in comparison to other materials the automotive application of these alloys is still low. The reasons for this are among other things the shortage of relevant materials values, insufficient knowledge concerning the correlation between the microstructure and the mechanical properties as well as deficits in relation to the die cast technology. This paper investigates the influence of the microstructure and manufacture-induced defects like micro-shrinkage and gas pores on the strength and deformability of the alloys AZ91, AM50 and AE42 under tensile and bend loading. To characterise the microstructure in the dependence on the wall thickness, the investigations are mainly carried out using in situ specimens obtained from die castings. (orig.)

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

    International Nuclear Information System (INIS)

    Nabiyouni, Maryam; Ren, Yufu; Bhaduri, Sarit B.

    2015-01-01

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

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

    Science.gov (United States)

    Nabiyouni, Maryam; Ren, Yufu; Bhaduri, Sarit B

    2015-01-01

    As biocompatible materials, magnesium phosphates have received a lot of attention for orthopedic applications. During the last decade multiple studies have shown advantages for magnesium phosphate such as lack of cytotoxicity, biocompatibility, strong mechanical properties, and high biodegradability. The present study investigates the role of Mg(+2) and Ca(+2) ions in the structure of magnesium phosphate and calcium phosphate nanoparticles. To directly compare the effect of Mg(+2) and Ca(+2) ions on structure of nanoparticles and their biological behavior, three groups of nanoparticles including amorphous magnesium phosphates (AMPs) which release Mg(+2), calcium magnesium phosphates (CMPs) which release Mg(+2) and Ca(+2), and hydroxyapatites (HAs) which release Ca(+2) were studied. SEM, TEM, XRD, and FTIR were used to evaluate the morphology, crystallinity, and chemical properties of the particles. AMP particles were homogeneous nanospheres, whereas CMPs were combinations of heterogeneous nanorods and nanospheres, and HAs which contained heterogeneous nanosphere particles. Cell compatibility was monitored in all groups to determine the cytotoxicity effect of particles on studied MC3T3-E1 preosteoblasts. AMPs showed significantly higher attachment rate than the HAs after 1 day and both AMPs and CMPs showed significantly higher proliferation rate when compared to HAs after 7days. Gene expression level of osteoblastic markers ALP, COL I, OCN, OPN, RUNX2 were monitored and they were normalized to GAPDH housekeeping gene. Beta actin expression level was monitored as the second housekeeping gene to confirm the accuracy of results. In general, AMPs and CMPs showed higher expression level of osteoblastic genes after 7 days which can further confirm the stimulating role of Mg(+2) and Ca(+2) ions in increasing the proliferation rate, differentiation, and mineralization of MC3T3-E1 preosteoblasts. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Lindsy Kass

    Full Text Available 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

  17. Yttrium ion implantation on the surface properties of magnesium

    International Nuclear Information System (INIS)

    Wang, X.M.; Zeng, X.Q.; Wu, G.S.; Yao, S.S.

    2006-01-01

    Owing to their excellent physical and mechanical properties, magnesium and its alloys are receiving more attention. However, their application has been limited to the high reactivity and the poor corrosion resistance. The aim of the study was to investigate the beneficial effects of ion-implanted yttrium using a MEVVA ion implanter on the surface properties of pure magnesium. Isothermal oxidation tests in pure O 2 at 673 and 773 K up to 90 min indicated that the oxidation resistance of magnesium had been significantly improved. Surface morphology of the oxide scale was analyzed using scanning electron microscope (SEM). Auger electron spectroscopy (AES) and X-ray diffraction (XRD) analyses indicated that the implanted layer was mainly composed of MgO and Y 2 O 3 , and the implanted layer with a duplex structure could decrease the inward diffusion of oxygen and reduce the outward diffusion of Mg 2+ , which led to improving the oxidation resistance of magnesium. Potentiodynamic polarization curves were used to evaluate the corrosion resistance of the implanted magnesium. The results show yttrium implantation could enhance the corrosion resistance of implanted magnesium compared with that of pure magnesium

  18. The history of biodegradable magnesium implants: a review.

    Science.gov (United States)

    Witte, Frank

    2010-05-01

    Today, more than 200years after the first production of metallic magnesium by Sir Humphry Davy in 1808, biodegradable magnesium-based metal implants are currently breaking the paradigm in biomaterial science to develop only highly corrosion resistant metals. This groundbreaking approach to temporary metallic implants is one of the latest developments in biomaterials science that is being rediscovered. It is a challenging topic, and several secrets still remain that might revolutionize various biomedical implants currently in clinical use. Magnesium alloys were investigated as implant materials long ago. A very early clinical report was given in 1878 by the physician Edward C. Huse. He used magnesium wires as ligature for bleeding vessels. Magnesium alloys for clinical use were explored during the last two centuries mainly by surgeons with various clinical backgrounds, such as cardiovascular, musculoskeletal and general surgery. Nearly all patients benefited from the treatment with magnesium implants. Although most patients experienced subcutaneous gas cavities caused by rapid implant corrosion, most patients had no pain and almost no infections were observed during the postoperative follow-up. This review critically summarizes the in vitro and in vivo knowledge and experience that has been reported on the use of magnesium and its alloys to advance the field of biodegradable metals. Copyright (c) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Witte, Frank

    2015-09-01

    Today, more than 200 years after the first production of metallic magnesium by Sir Humphry Davy in 1808, biodegradable magnesium-based metal implants are currently breaking the paradigm in biomaterial science to develop only highly corrosion resistant metals. This groundbreaking approach to temporary metallic implants is one of the latest developments in biomaterials science that is being rediscovered. It is a challenging topic, and several secrets still remain that might revolutionize various biomedical implants currently in clinical use. Magnesium alloys were investigated as implant materials long ago. A very early clinical report was given in 1878 by the physician Edward C. Huse. He used magnesium wires as ligature for bleeding vessels. Magnesium alloys for clinical use were explored during the last two centuries mainly by surgeons with various clinical backgrounds, such as cardiovascular, musculoskeletal and general surgery. Nearly all patients benefited from the treatment with magnesium implants. Although most patients experienced subcutaneous gas cavities caused by rapid implant corrosion, most patients had no pain and almost no infections were observed during the postoperative follow-up. This review critically summarizes the in vitro and in vivo knowledge and experience that has been reported on the use of magnesium and its alloys to advance the field of biodegradable metals. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. Dose-response relationship between dietary magnesium intake, serum magnesium concentration and risk of hypertension: a systematic review and meta-analysis of prospective cohort studies.

    Science.gov (United States)

    Han, Hedong; Fang, Xin; Wei, Xin; Liu, Yuzhou; Jin, Zhicao; Chen, Qi; Fan, Zhongjie; Aaseth, Jan; Hiyoshi, Ayako; He, Jia; Cao, Yang

    2017-05-05

    The findings of prospective cohort studies are inconsistent regarding the association between dietary magnesium intake and serum magnesium concentration and the risk of hypertension. We aimed to review the evidence from prospective cohort studies and perform a dose-response meta-analysis to investigate the relationship between dietary magnesium intake and serum magnesium concentrations and the risk of hypertension. We searched systematically PubMed, EMBASE and the Cochrane Library databases from October 1951 through June 2016. Prospective cohort studies reporting effect estimates with 95% confidence intervals (CIs) for hypertension in more than two categories of dietary magnesium intake and/or serum magnesium concentrations were included. Random-effects models were used to combine the estimated effects. Nine articles (six on dietary magnesium intake, two on serum magnesium concentration and one on both) of ten cohort studies, including 20,119 cases of hypertension and 180,566 participates, were eligible for inclusion in the meta-analysis. We found an inverse association between dietary magnesium intake and the risk of hypertension [relative risk (RR) = 0.92; 95% CI: 0.86, 0.98] comparing the highest intake group with the lowest. A 100 mg/day increment in magnesium intake was associated with a 5% reduction in the risk of hypertension (RR = 0.95; 95% CI: 0.90, 1.00). The association of serum magnesium concentration with the risk of hypertension was marginally significant (RR = 0.91; 95% CI: 0.80, 1.02). Current evidence supports the inverse dose-response relationship between dietary magnesium intake and the risk of hypertension. However, the evidence about the relationship between serum magnesium concentration and hypertension is limited.

  1. Magnesium Hall Thruster

    Science.gov (United States)

    Szabo, James J.

    2015-01-01

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

  2. Oxidation behavior of molten magnesium in atmospheres containing SO2

    International Nuclear Information System (INIS)

    Wang Xianfei; Xiong Shoumei

    2011-01-01

    Graphical abstract: Highlights: → We found the film formed on molten magnesium had a two or three layers structure. → The formation mechanism of film was investigated and a growth model was proposed. → We found the formation of MgSO 4 was critical and promoted the growth of the film. - Abstract: The microchemistry and morphology of the oxide layer formed on molten magnesium in atmospheres containing SO 2 were examined. Based on the results and the thermodynamic and kinetic calculations of oxide-growth process, a schematic oxidation mechanism is presented. The results showed that the oxide scales with network structure were generally composed of MgO, MgS, and MgSO 4 with different layers, depending on the SO 2 content, the time and the temperature. The formation of MgSO 4 was important for the formation of the protective oxide scales. The growth of the oxide scales followed the parabolic law at 973 K and was controlled by diffusion.

  3. Electrolytes for magnesium electrochemical cells

    Science.gov (United States)

    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.

  4. Magnesium - distribution and basic metabolism

    African Journals Online (AJOL)

    Magnesium is extensively distributed in soil, water and plants. It is essential for ehzymatic reactions requiring adenosine triphosphate, and the recom- mended dietary allowance in man is 5 - 10 mg/kg/d. About 50% of magnesium in man is stored ~n bone, where it is regulated by parathyroid hormone'and. 1,25(OHb-D3.

  5. Hydrostatic extrusion of magnesium alloys

    NARCIS (Netherlands)

    Sillekens, W.H.; Bohlen, J.

    2012-01-01

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

  6. Magnesium in Prevention and Therapy

    Science.gov (United States)

    Gröber, Uwe; Schmidt, Joachim; Kisters, Klaus

    2015-01-01

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

  7. Magnesium in Prevention and Therapy

    Directory of Open Access Journals (Sweden)

    Uwe Gröber

    2015-09-01

    Full Text Available 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.

  8. Innovative Vacuum Distillation for Magnesium Recycling

    Science.gov (United States)

    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.

  9. Impact of magnesium:calcium ratio on calcification of the aortic wall.

    Science.gov (United States)

    Villa-Bellosta, Ricardo

    2017-01-01

    An inverse relationship between serum magnesium concentration and vascular calcification has been reported following observational clinical studies. Moreover, several studies have been suggesting a protective effect of magnesium on the vascular calcification. However, the exact mechanism remains elusive, and investigators have speculated among a myriad of potential actions. The effect of magnesium on calcification of the aortic wall is yet to be investigated. In the present study, the effects of magnesium and calcium on the metabolism of extracellular PPi, the main endogenous inhibitor of vascular calcification, were investigated in the rat aorta. Calcium and magnesium have antagonist effects on PPi hydrolysis in the aortic wall. Km and Ki values for PPi hydrolysis in rat aortic rings were 1.1 mmol/L magnesium and 32 μmol/L calcium, respectively, but ATP hydrolysis was not affected with calcium. Calcium deposition in the rat aortic wall dramatically increased when the magnesium concentration was increased (ratio of Mg:Ca = 1:1; 1.5 mmol/L calcium and 1.5 mmol/L magnesium) respect to low magnesium concentration (ratio Mg:Ca = 1:3, 1.5 mmol/L calcium and 0.75 mmol/L magnesium). Data from observational clinical studies showing that the serum magnesium concentration is inversely correlated with vascular calcification could be reinterpreted as a compensatory regulatory mechanism that reduces both PPi hydrolysis and vascular calcification. The impact of magnesium in vascular calcification in humans could be studied in association with calcium levels, for example, as the magnesium:calcium ratio.

  10. Investigation of the dependency of wind turbine loads on the simulation time

    OpenAIRE

    Tibaldi, Carlo; Henriksen, Lars Christian; Bak, Christian

    2014-01-01

    In this work the dependency of several wind turbine parameters with respect to the length of simulations used for their evaluation is investigated. The analysis is performed by computing the parameters with a different number of turbulent wind simulations, therefore simulation time, and repeating the computation with different turbulence realizations. The repetition of the computation is performed to identify the scatter of the parameters for a given number of turbulent seeds due to the diffe...

  11. Influence of Cobalt on the Properties of Load-Sensitive Magnesium Alloys

    Directory of Open Access Journals (Sweden)

    Kai Kerber

    2012-12-01

    Full Text Available In this study, magnesium is alloyed with varying amounts of the ferromagnetic alloying element cobalt in order to obtain lightweight load-sensitive materials with sensory properties which allow an online-monitoring of mechanical forces applied to components made from Mg-Co alloys. An optimized casting process with the use of extruded Mg-Co powder rods is utilized which enables the production of magnetic magnesium alloys with a reproducible Co concentration. The efficiency of the casting process is confirmed by SEM analyses. Microstructures and Co-rich precipitations of various Mg-Co alloys are investigated by means of EDS and XRD analyses. The Mg-Co alloys’ mechanical strengths are determined by tensile tests. Magnetic properties of the Mg-Co sensor alloys depending on the cobalt content and the acting mechanical load are measured utilizing the harmonic analysis of eddy-current signals. Within the scope of this work, the influence of the element cobalt on magnesium is investigated in detail and an optimal cobalt concentration is defined based on the performed examinations.

  12. 21 CFR 184.1443 - Magnesium sulfate.

    Science.gov (United States)

    2010-04-01

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

  13. Combustion and extinction of magnesium fires

    International Nuclear Information System (INIS)

    Malet, J.C.; Duverger de Cuy, G.

    1988-01-01

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

  14. Mineral resource of the month: magnesium

    Science.gov (United States)

    Kramer, Deborah A.

    2012-01-01

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

  15. Magnesium deficiency: What is our status

    Science.gov (United States)

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

  16. 21 CFR 184.1431 - Magnesium oxide.

    Science.gov (United States)

    2010-04-01

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

  17. 21 CFR 184.1426 - Magnesium chloride.

    Science.gov (United States)

    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... hydrochloric acid solution and crystallizing out magnesium chloride hexahydrate. (b) The ingredient meets the...

  18. Investigation of the Microstructure Evolution and Deformation Mechanisms of a Mg-Zn-Zr-RE Twin-Roll-Cast Magnesium Sheet by In-Situ Experimental Techniques.

    Science.gov (United States)

    Máthis, Kristián; Horváth, Klaudia; Farkas, Gergely; Choe, Heeman; Shin, Kwang Seon; Vinogradov, Alexei

    2018-01-27

    Twin roll casting (TRC), with a relatively fast solidification rate, is an excellent production method with promising potential for producing wrought semi or final Mg alloy products that can often suffer from poor formability. We investigate in this study the effect of the TRC method and the subsequent heat treatment on the microstructure and deformation mechanisms in Mg-Zn-Zr-Nd alloy deformed at room temperature using the in-situ neutron diffraction and acoustic emission techniques and ex-situ texture measurement and microscopy, respectively. Although a higher work hardening is observed in the rolling direction due to the more intensive -type dislocation activity, the difference in the mechanical properties of the specimens deformed in the RD and TD directions is small in the as-rolled condition. An additional heat treatment results in recrystallization and significant anisotropy in the deformation. Due to the easier activation of the extension twinning in the TD given by texture, the yield stress in the TD is approximately 40% lower than that in the RD.

  19. MAGNESIUM, DRINKING WATER HARDNESS AND CARDIOVASCULAR DISEASE

    Directory of Open Access Journals (Sweden)

    Dragana Nikic

    2006-01-01

    Full Text Available Many different countries suggest and justify an integrated laboratory and epidemiological research program with an aim to reject or accept the magnesium – CVD (cardiovascular disease hypothesis. The studies shown in this paper that have investigated the relationship between water hardness, especially magnesium and CVD indicate that, even though there has been an ongoing research for nearly half a century (1957-2004, it has not been completed yet. Different study designs (obductional, clinical, ecological, case-control and cohort restrict an adequate comparison of their results as well as the deduction of results applicable on each territorial level.The majority of researchers around the world, using populational and individual studies, have found an inverse (protective association between mortality and morbidity from CVD and the increase in water hardness, especially the increase in the concentration of magnesium. The most frequent benefit of the water with an optimal mineral composition is the reduction of mortality from ischemic heart disease.It was suggested that Mg from water is a supplementary source of Mg of high biological value, because magnesium from water is absorbed around 30% better than Mg in a diet. The vast majority of studies consider lower concentrations of Mg in the water, in the range of 10% of the total daily intake of Mg.Future research efforts must give better answers to low Mg concentrations in the drinking water, before any concrete recommendations are given to the public. Moreover, the researchers must also determine which chemical form of Mg is most easily absorbed and has the greatest impact.Additional research is necessary in order to further investigate the interrelation between different water and food components as well as individual risk factors in the pathogenesis of CVD.

  20. Numerical Investigation of Structural Response of Corrugated Blast Wall Depending on Blast Load Pulse Shapes

    Directory of Open Access Journals (Sweden)

    Jung Min Sohn

    Full Text Available Abstract Hydrocarbon explosions are one of most hazardous events for workers on offshore platforms. To protect structures against explosion loads, corrugated blast walls are typically installed. However, the profiles of real explosion loads are quite different depending on the congestion and confinement of Topside structures. As the level of congestion and confinement increases, the explosion load increases by up to 8 bar, and the rising time of the load decreases. This study primarily aims to investigate the structural behavior characteristics of corrugated blast walls under different types of explosion loadings. Four loading shapes were applied in the structural response analysis, which utilized a dynamic nonlinear finite element method.

  1. Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid.

    Science.gov (United States)

    Lidong, Wang; Yongliang, Ma; Wendi, Zhang; Qiangwei, Li; Yi, Zhao; Zhanchao, Zhang

    2013-08-15

    Magnesia flue gas desulfurization is a promising process for small to medium scale industrial coal-fired boilers in order to reduce sulfur dioxide emissions, in which oxidation control of magnesium sulfite is of great importance for the recycling of products. Effects of four inhibitors were compared by kinetic experiments indicating that ascorbic acid is the best additive, which retards the oxidation process of magnesium sulfite in trace presence. The macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid were studied. Effects of the factors, including ascorbic acid concentration, magnesium sulfite concentration, oxygen partial pressure, pH, and temperature, were investigated in a stirred reactor with bubbling. The results show that the reaction rate is -0.55 order in ascorbic acid, 0.77 in oxygen partial pressure, and zero in magnesium sulfite concentration, respectively. The apparent activation energy is 88.0 kJ mol(-1). Integrated with the kinetic model, it is concluded that the oxidation rate of magnesium sulfite inhibited by ascorbic acid is controlled by the intrinsic chemical reaction. The result provides a useful reference for sulfite recovery in magnesia desulfurization. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Viral prevalence and laboratory investigations of gastroenteritis in institutions for dependent people.

    Science.gov (United States)

    Gaspard, P; Pothier, P; Roth, C; Larocca, S; Heck, B; Ambert-Balay, K

    2017-12-01

    Viruses are recognized as important agents of gastroenteritis outbreaks in institutions caring for dependent people. We aimed to define norovirus (NoV) and rotavirus (RV) immunochromatographic tests (ICT) and reverse transcription-polymerase chain reaction (RT-PCR) used in gastroenteritis investigations. Fourteen sites were monitored from 2010 to 2015, with 360 laboratory investigations. Twenty-two outbreaks and 44 sporadic case patients were investigated with ICTs (114 NoVs and 80 RVs) and RT-PCRs (114 NoVs and 52 RVs). ICTs were useful during outbreaks (identification of NoVs and RVs in respectively 76.5% and 75.0% of episodes) despite the NoV sensitivity limit (55.1%) and the four RV false positive results observed for 10 samples. Given the NoV ICT performance and the observed variations of the NoV and RV prevalence (between 20.0% and 5.0%), ICTs are not appropriate to identify sporadic gastroenteritis case patients. Positive predictive values ICT during outbreaks, control of positive RV ICT in cases of suspected NoV and RV co-circulation, patients with long symptom duration, and NoV genogroup and genotype identifications (infection control and epidemiological surveillance). Inclusion of patients with specific clinical symptoms is recommended irrespective of the technique. On the basis of the ICT limits identified in this work, RT-PCR development seems essential to improve viral gastroenteritis investigations in institutions caring for dependent people. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Erythrocyte magnesium fluxes in mice with nutritionally and genetically low magnesium status.

    Science.gov (United States)

    Feillet-Coudray, Christine; Trzeciakiewicz, A; Coudray, C; Rambeau, M; Chanson, A; Rayssiguier, Y; Opolski, A; Wolf, F I; Mazur, A

    2006-03-01

    Low intracellular magnesium (Mg) contents may be observed in case of severe Mg insufficient intake or because of genetic regulation. This work was conducted to investigate the influence of intracellular Mg content on erythrocyte Mg(2+) influx and efflux in mice with low nutritionally and genetically (MGL and MGH mice) Mg status. C57BL6 mice were fed for 2 wks a diet containing 1000 mg Mg/kg diet Mg (control group), 100 mg Mg/kg diet (Mg-marginal group) or 30 mg Mg/kg diet (Mg deficient group), while mice with low (MGL) and high (MGH) Mg levels were fed a control diet for 2 wks. The quantification of erythrocyte Mg(2+) influx and efflux was performed using a stable isotope of Mg. Our results showed that erythrocyte Mg(2+) influx and efflux were respectively increased and decreased in nutritional Mg deficiency; while in genetically determined Mg status Mg(2+) fluxes were lower in MGL mice compared to MGH mice. Moreover Mg(2+) efflux was significantly correlated to Mg level in erythrocytes in all the mice studied (p low Mg status, namely decreased Mg(2+) efflux compensate for nutritional Mg deficiency, while the genetic regulation of erythrocyte Mg(2+) content depends on modification of Mg(2+) influx.

  4. [Progress of in vivo study on degradable magnesium alloys application as bone-implant materials].

    Science.gov (United States)

    Qi, Zhengrong; Zhang, Qiang; Yin, Yi; Wang, Yan

    2012-11-01

    To review the progress of in vivo study on degradable magnesium alloys application as bone-implant materials. Recent literature was extensively reviewed and summarized, concerning the in vivo study on degradable magnesium alloys as orthopaedic implants. Magnesium alloys possess a natural ability to degrade via corrosion in vivo, which is promising candidate material for orthopaedic medical device applications. A great progress has been made to improve in vivo performance and integration with bone tissue. However, the degradation mechanism of magnesium-based materials in the physiological environment and long-term effect on body are not available. The modulation of the corrosion rate of magnesium alloys must also be accomplished. Magnesium alloys have the potential to serve as degradable implants for orthopaedic applications, but a great deal of further investigation is still necessary.

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

    Directory of Open Access Journals (Sweden)

    Rajan Choudhary

    2015-06-01

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

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

    International Nuclear Information System (INIS)

    Chew, K.V.; Haseeb, A.S.M.A.; Masjuki, H.H.; Fazal, M.A.; Gupta, M.

    2013-01-01

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

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

    Science.gov (United States)

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

    2015-08-15

    The aim of this research was to investigate the effect of magnesium on the removal efficiency of sulphate as gypsum from mine water. The precipitation conditions were simulated with MINEQL + software and the simulation results were compared with the results from laboratory jar test experiments. Both the simulation and the laboratory results showed that magnesium in the mine water was maintaining sulphate in a soluble form as magnesium sulphate (MgSO4) at pH 9.6. Thus magnesium was preventing the removal of sulphate as gypsum (CaSO4·2H2O). However, change in the lime precipitation pH from 9.6 to 12.5 resulted in magnesium hydroxide (Mg(OH)2) precipitation and improved sulphate removal. Additionally, magnesium hydroxide could act as seed crystals for gypsum precipitation or co-precipitate sulphate further enhancing the removal of sulphate from mine water. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    OpenAIRE

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

    1980-01-01

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

  9. Mechanical analysis on magnesium alloy rotating mirror for ultra-high-speed camera

    Science.gov (United States)

    Li, Chunbo; Liu, Minqiu; Ren, Xikui; Du, Chenlin; Huang, Hongbin; Ruan, Shuangchen

    2018-03-01

    Rotating mirror is not only as an imaging element in optical path of ultra-high speed camera, where imaging quality is affected by surface quality and plane deformation of the rotating mirror, but also as an element to implement ultra-high speed, because performances of the ultra-high-speed camera system are mainly dependent on the static and dynamic mechanical properties of the rotating mirror. In this paper, the static and dynamic properties of magnesium alloy rotating mirror with equilateral-triangle cross-sections were investigated by theoretically and numerically method. At the speed of 2×105 rpm, the maximum lateral deformations of the mirror facet with width 17.32 mm and length 40 mm is 2.476 μm. The maximum von Mises stress is 35.1 MPa. The deformation and stress are less than that of aluminum alloy rotating mirror, which has been successfully applied in many types of RM for ultra-high speed cameras. The first three frequencies of magnesium alloy rotating mirror are 9,539.9 Hz, 9,540.9 Hz and 12,726.0 Hz, respectively. While the first three frequencies of aluminium alloy rotating-mirror are 9,683.9 Hz, 9,685.2 Hz and 11,016.0 Hz. From which it is preliminarily shown that a magnesium alloy rotating mirror can be used as replacement for an aluminium alloy rotating mirror in ultra-high-speed camera.

  10. Effect of cutting parameters on machinability characteristics in milling of magnesium alloy with carbide tool

    Directory of Open Access Journals (Sweden)

    Kaining Shi

    2016-01-01

    Full Text Available Magnesium alloy has attracted more attentions due to its excellent mechanical properties. However, in process of dry cutting operation, many problems restrict its further development. In this article, the effect of cutting parameters on machinabilities of magnesium alloy is explored under dry milling condition. This research is an attempt to investigate the impact of cutting speed at multiple feed rates on cutting force and surface roughness, while a statistical analysis is adopted to determine the influential intensities accurately. The results showed that cutting force is affected by the positively constant intensity from feed rate and the increasingly negative intensity from cutting speed. In contrast, surface roughness is determined by the gradually increasing negative tendency from feed rate and the positive effect with constant intensity from cutting speed. Within the range of the experiments, feed rate is the leading contribution for cutting force while the cutting speed is the dominant factor for surface roughness according to the absolute intensity values. Meanwhile, the trends of influencing intensities between cutting force and surface roughness are opposite. Besides, it is also found that in milling magnesium alloy, chip morphology is highly sensitive to cutting speed while the chip quality mainly depends on feed rate.

  11. Thermodynamic criteria for the removal of impurities from end-of-life magnesium alloys by evaporation and flux treatment

    Directory of Open Access Journals (Sweden)

    Takehito Hiraki, Osamu Takeda, Kenichi Nakajima, Kazuyo Matsubae, Shinichiro Nakamura and Tetsuya Nagasaka

    2011-01-01

    Full Text Available In this paper, the possibility of removing impurities during magnesium recycling with pyrometallurgical techniques has been evaluated by using a thermodynamic analysis. For 25 different elements that are likely to be contained in industrial magnesium alloys, the equilibrium distribution ratios between the metal, slag and gas phases in the magnesium remelting process were calculated assuming binary systems of magnesium and an impurity element. It was found that calcium, gadolinium, lithium, ytterbium and yttrium can be removed from the remelted end-of-life (EoL magnesium products by oxidization. Calcium, cerium, gadolinium, lanthanum, lithium, plutonium, sodium, strontium and yttrium can be removed by chlorination with a salt flux. However, the other elements contained in magnesium alloy scrap are scarcely removed and this may contribute toward future contamination problems. The third technological option for the recycling of EoL magnesium products is magnesium recovery by a distillation process. Based on thermodynamic considerations, it is predicted that high-purity magnesium can be recovered through distillation because of its high vapor pressure, yet there is a limit on recoverability that depends on the equilibrium vapor pressure of the alloying elements and the large energy consumption. Therefore, the sustainable recycling of EoL magnesium products should be an important consideration in the design of advanced magnesium alloys or the development of new refining processes.

  12. Investigating the context-dependency of plant-soil-AMF-microbe interactions along a pollution gradient

    Science.gov (United States)

    Glassman, S. I.; Casper, B. B.

    2010-12-01

    Background/Question/Methods Investigating how arbuscular mycorrhizal fungi (AMF)-plant interactions vary with edaphic conditions provides an opportunity to test the context-dependency of interspecific interactions, which is currently recognized as a major avenue of future research. We study plant-mycorrhiza symbiotic relationships along a gradient of heavy metal contamination at a recently revegetated “Superfund” site on Blue Mountain, in Palmerton, Pennsylvania. We investigated the interactions involving the native mycorrhizal fungi, non-mycorrhizal soil microbes, soil, and two plant species (a C3 and C4 grass) along the contamination gradient. The native C3 study species Deschampsia flexuosa, is dominant along the gradient and established naturally; the C4 Sorghastrum nutans, is native to Pennsylvania but not to the site and was introduced during restoration. Because C4 grasses are obligate mycotrophs, we expected S. nutans to have a different effect on and response to the soil symbiont community than the C3 grass. We carried out a full factorial greenhouse experiment using field-collected seeds of D. flexuosa and S. nutans, soil, AMF spores, and non-mycorrhizal microbes from both high and low contaminated ends of the gradient. After 11 weeks of growth in the greenhouses, we harvested above and belowground plant biomass, and quantified AMF root colonization and AMF sporulation. Results/Conclusions Our results indicate that context-dependent function is an important factor driving specific ecological interactions between plants and soil microbes. We found that soil origin significantly affected plant growth. Plants from both species grew much larger in soil from low contaminated (LC) origin than high contaminated (HC) origin. Furthermore, we found that the efficacy of AMF in promoting plant growth depended on AMF origin. Specifically, AMF from LC improved growth of D. flexuosa best in either soil background and improved survivorship of S. nutans in HC soil

  13. Research of magnesium phosphosilicate cement

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2011-12-01

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

  15. ESR dosimetry with magnesium sulphate

    International Nuclear Information System (INIS)

    Morton, J.R.; Ahlers, F.J.; Schneider, C.C.J.

    1993-01-01

    The aim of the investigation is to enhance the ESR dosemeter sensitivity in the therapy dose range below 10 Gy, where the ESR spectrum of the α-alanine radical becomes increasingly difficult to evaluate for dosimetry. Anhydrous magnesium sulphate, MgSO 4 , appears to be an excellent candidate from the spectrometric point of view. On irradiation with 60 Co γ rays, the stable radical SO 3 - is produced whose ESR signal amplitude increases linearly with dose up to about 10 5 Gy. Ignoring the abundant isotopes 17 O (0.04%) and 33 S (0.74%), the spectrum of SO 3 - is a single line at g = 2.0036 of width 0.5 mT which is stable at temperatures up to at least 120 o C. Using the conventional peak-to-peak method of dosimeter readout, the MgSO 4 dosemeter is somewhat more sensitive than the traditional alanine dosemeter of the same mass. Its main advantage over the alanine dosemeter is, however, the ease of computer enhancement and the possibility of integration which the single-line spectrum offers. (author)

  16. Investigation of the toroidal dependence of first wall conditions in the Large Helical Device

    International Nuclear Information System (INIS)

    Hino, T.; Ashikawa, N.; Masuzaki, S.; Sagara, A.; Komori, A.; Yamauchi, Y.; Nobuta, Y.; Matsunaga, Y.

    2010-11-01

    The non-uniform wall conditions such as the fuel hydrogen retention and the erosion/deposition have been investigated in the Large Helical Device (LHD) by using toroidally and poloidally distributed material probes. They were installed in every experimental campaign from 2003 to 2010, and the evolutions of the wall conditions were clearly obtained. The wall conditions significantly depended on the operational procedures and the positions of in-vessel devices such as anodes for glow discharge and the ICRF antennas. The toroidal profiles for the amounts of retained hydrogen and helium, and the depth of wall erosion, were systematically measured. The hydrogen, helium and neon glow discharges have been conducted by using two anodes before and after the hydrogen or helium main discharges. The amount of retained hydrogen was large in the vicinity of the anodes, and drastically decreased as increase of the campaign number. This reduction well corresponds to the time period used for the hydrogen glow discharge conditioning. The erosion depth was large at the walls relatively close to the anodes, which is owing to the sputtering during the helium and neon glow discharges. The depositions of carbon and boron also depended on the positions of NBI and diborane gas inlet used for boronization, respectively. The amount of the retained helium was large at the walls close to the anodes owing to the helium glow discharge. The amount of retained helium became large at the walls close to the ICRF antennas owing to the implantation of high energy helium during the helium main discharge with the ICRF heating. In the present study, the toroidal dependences of the gas retention and the erosion/deposition in LHD were obtained, and the effects of the in-vessel devices on these plasma wall interactions were clarified. (author)

  17. Effect of different concentrations of potassium and magnesium on ...

    African Journals Online (AJOL)

    The rate of root colonization by mycorrhizal fungi largely depends on the concentration of nutrient elements in roots and soil. In this study, the effects of different concentrations of potassium and magnesium on mycorrhizal colonization of maize grown in pot cultures were studied. This experiment was performed using natural ...

  18. Numerical investigation of time-dependent cloud cavitating flow around a hydrofoil

    Directory of Open Access Journals (Sweden)

    Zhang De-Sheng

    2016-01-01

    Full Text Available Time-dependent cloud cavitation around the 2-D Clark-Y hydrofoil was investigated in this paper based on an improved filter based model and a density correction method. The filter-scale in filter based model simulation was discussed and validated according to the grid size. Numerical results show that in the transition from sheet cavitation to cloud cavitation, the sheet cavity grows slowly to the maximum length during the re-entrant jet develops. The mild shedding bubble cluster convects downwards the hydrofoil and continues to grow up after detaching from the suction surface of hydrofoil, and a bubble cluster introduced at the rear part of hydrofoil. While the sheet cavity generates, the bubble cluster breakups.

  19. Rheological Investigation on the Effect of Shear and Time Dependent Behavior of Waxy Crude Oil

    Directory of Open Access Journals (Sweden)

    Japper-Jaafar A.

    2014-07-01

    Full Text Available Rheological measurements are essential in transporting crude oil, especially for waxy crude oil. Several rheological measurements have been conducted to determine various rheological properties of waxy crude oil including the viscosity, yield strength, wax appearance temperature (WAT, wax disappearance temperature (WDT, storage modulus and loss modulus, amongst others, by using controlled stress rheometers. However, a procedure to determine the correct parameters for rheological measurements is still unavailable in the literature. The paper aims to investigate the effect of shear and time dependent behaviours of waxy crude oil during rheological measurements. It is expected that the preliminary work could lead toward a proper rheological measurement guideline for reliable rheological measurement of waxy crude oil.

  20. Investigation of the redox-dependent modulation of structure and dynamics in human cytochrome c

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Mizue [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810 (Japan); Saio, Tomohide [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810 (Japan); Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Kumeta, Hiroyuki [Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021 (Japan); Uchida, Takeshi [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810 (Japan); Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Inagaki, Fuyuhiko [Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021 (Japan); Ishimori, Koichiro, E-mail: koichiro@sci.hokudai.ac.jp [Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810 (Japan); Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan)

    2016-01-22

    Redox-dependent changes in the structure and dynamics of human cytochrome c (Cyt c) were investigated by solution NMR. We found significant structural changes in several regions, including residues 23–28 (loop 3), which were further corroborated by chemical shift differences between the reduced and oxidized states of Cyt c. These differences are essential for discriminating redox states in Cyt c by cytochrome c oxidase (CcO) during electron transfer reactions. Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments identified that the region around His33 undergoes conformational exchanges on the μs-ms timescale, indicating significant redox-dependent structural changes. Because His33 is not part of the interaction site for CcO, our data suggest that the dynamic properties of the region, which is far from the interaction site for CcO, contribute to conformational changes during electron transfer to CcO. - Highlights: • Solution structure and dynamics analysis for human Cyt c by NMR. • Structural changes responsible for the discrimination of the redox state in Cyt c. • Conformational exchange in the region outside of the interaction site for CcO. • Less flexibility and rigid structure of the interaction site on Cyt c for CcO.

  1. Investigation of the field dependent spin structure of exchange coupled magnetic heterostructures

    International Nuclear Information System (INIS)

    Gurieva, Tatiana

    2016-05-01

    This thesis describes the investigation of the field dependent magnetic spin structure of an antiferromagnetically (AF) coupled Fe/Cr heterostructure sandwiched between a hardmagnetic FePt buffer layer and a softmagnetic Fe top layer. The depth-resolved experimental studies of this system were performed via Magneto-optical Kerr effect (MOKE), Vibrating Sample Magnetometry (VSM) and various measuring methods based on nuclear resonant scattering (NRS) technique. Nucleation and evolution of the magnetic spiral structure in the AF coupled Fe/Cr multilayer structure in an azimuthally rotating external magnetic field were observed using NRS. During the experiment a number of time-dependent magnetic side effects (magnetic after-effect, domain-wall creep effect) caused by the non-ideal structure of a real sample were observed and later explained. Creation of the magnetic spiral structure in rotating external magnetic field was simulated using a one-dimensional micromagnetic model.The cross-sectional magnetic X-ray diffraction technique was conceived and is theoretically described in the present work. This method allows to determine the magnetization state of an individual layer in the magnetic heterostructure. It is also applicable in studies of the magnetic structure of tiny samples where conventional x-ray reflectometry fails.

  2. Requirements for investigating the temperature-dependent fracture behavior of irradiated materials by indentation

    Energy Technology Data Exchange (ETDEWEB)

    Sacksteder, Irène, E-mail: irene.sacksteder@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, Eggenstein-Leopoldshafen (Germany); Hostettler, Simon [Synton-MDP Inc., Nidau (Switzerland); Charbonneau, Grégoire; Albinski, Bartlomiej; Schneider, Hans-Christian [Karlsruhe Institute of Technology, Institute for Applied Materials, Eggenstein-Leopoldshafen (Germany)

    2013-10-15

    Highlights: • A custom-made indenter is designed for indentations at high temperature. • The instrumented indentation technique at high temperature will be used to investigate temperature dependent fracture mechanisms in structural materials. • A finite-element based model has been validated with a view to predict crack initiation and propagation in Eurofer97 and tungsten-like materials. -- Abstract: The instrumented indentation technique is an interesting testing tool to examine temperature-dependent fracture mechanisms. It is planned to be used to generate cracks at defined temperatures in hard and brittle metallic materials. The present study describes the properties needed for the use of a new type of indenter operating at high temperature. The indenter was designed to meet mechanical and thermal requirements and other constraints relating to the operation of functional units of the indentation instrument. Additionally, a finite element model has been built with a view to predict indentation induced cracks in Eurofer97 and tungsten. The model has been validated both with the theory of Hertz and experimentally by comparison with indentation curves.

  3. Investigation of the pH-dependence of dye-doped protein-protein interactions.

    Science.gov (United States)

    Nudelman, Roman; Gloukhikh, Ekaterina; Rekun, Antonina; Richter, Shachar

    2016-11-01

    Proteins can dramatically change their conformation under environmental conditions such as temperature and pH. In this context, Glycoprotein's conformational determination is challenging. This is due to the variety of domains which contain rich chemical characters existing within this complex. Here we demonstrate a new, straightforward and efficient technique that uses the pH-dependent properties of dyes-doped Pig Gastric Mucin (PGM) for predicting and controlling protein-protein interaction and conformation. We utilize the PGM as natural host matrix which is capable of dynamically changing its conformational shape and adsorbing hydrophobic and hydrophilic dyes under different pH conditions and investigate and control the fluorescent properties of these composites in solution. It is shown at various pH conditions, a large variety of light emission from these complexes such as red, green and white is obtained. This phenomenon is explained by pH-dependent protein folding and protein-protein interactions that induce different emission spectra which are mediated and controlled by means of dye-dye interactions and surrounding environment. This process is used to form the technologically challenging white light-emitting liquid or solid coating for LED devices. © 2016 The Protein Society.

  4. Investigation of temperature dependent barrier height of Au/ZnO/Si schottky diodes

    International Nuclear Information System (INIS)

    Asghar, M.; Mahmood, K.; Rabia, S.; BM, S.; Shahid, M. Y.; Hasan, M. A.

    2013-01-01

    In this study, temperature dependent current-voltage (I-V) measurements have been performed to investigate the inhomogeneity in the temperature dependent barrier heights of Au/ZnO/Si Schottky barrier diode in the temperature range 150 - 400K. The room temperature values for ideality factor and barrier height were found to be 2.9 and 0.60 eV respectively indicating the inhomogenity in the barrier heights of grown samples. The Richardson plot and ideality factor verses barrier height graph were also drawn to verified the discontinuity between Au and ZnO. This barrier height inhomogenity was explained by applying Gaussian distribution model. The extrapolation of the linear Fap (n) plot to n= 1 has given a homogeneous barrier height of approximately 1.1 eV. Fap versus 1/T plot was drawn to obtain the values of mean barrier height for Au/ZnO/Si Schottky diode (1.1 eV) and standard deviation(ds) (0.02 V) at zero bais. (author)

  5. Investigation of temperature dependent barrier height of Au/ZnO/Si schottky diodes

    International Nuclear Information System (INIS)

    Asghar, M; Mahmood, K; Rabia, S; M, Samaa B; Shahid, M Y; Hasan, M A

    2014-01-01

    In this study, temperature dependent current-voltage (I-V) measurements have been performed to investigate the inhomogeneity in the temperature dependent barrier heights of Au/ZnO/Si Schottky barrier diode in the temperature range 150 – 400K. The room temperature values for ideality factor and barrier height were found to be 2.9 and 0.60 eV respectively indicating the inhomogenity in the barrier heights of grown samples. The Richardson plot and ideality factor verses barrier height graph were also drawn to verified the discontinuity between Au and ZnO. This barrier height inhomogenity was explained by applying Gaussian distribution model. The extrapolation of the linear Φ ap (n) plot to n= 1 has given a homogeneous barrier height of approximately 1.1 eV. Φ ap versus 1/T plot was drawn to obtain the values of mean barrier height for Au/ZnO/Si Schottky diode (1.1 eV) and standard deviation(δ s ) (0.02 V) at zero bais

  6. Properties of porous magnesium prepared by powder metallurgy.

    Science.gov (United States)

    Čapek, Jaroslav; Vojtěch, Dalibor

    2013-01-01

    Porous magnesium-based materials are biodegradable and promising for use in orthopaedic applications, but their applications are hampered by their difficult fabrication. This work reports the preparation of porous magnesium materials by a powder metallurgy technique using ammonium bicarbonate as spacer particles. The porosity of the materials depended on the amount of ammonium bicarbonate and was found to have strong negative effects on flexural strength and corrosion behaviour. However, the flexural strength of materials with porosities of up to 28 vol.% was higher than the flexural strength of non-metallic biomaterials and comparable with that of natural bone. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. The distribution of Magnesium, Zinc & Copper in the skin and hair of ...

    African Journals Online (AJOL)

    The distribution of magnesium, zinc and copper was investigated in the hair and skin of African dwarf sheep. The 3 elements were found to be present in varying degrees in these organs. All were more abundant in the hair than in the skin. For instance, 2026 ppm were the highest amount of magnesium found in the hair ...

  8. Comparison between magnesium sulfate and dexmedetomidine in controlled hypotension during functional endoscopic sinus surgery

    OpenAIRE

    Adnan Bayram; Ayse Ülgey; Isin Günes; Ibrahim Ketenci; Ayse Çapar; Aliye Esmaoglu; Adem Boyaci

    2015-01-01

    BACKGROUND AND OBJECTIVES: It is crucial to decrease bleeding during functional endoscopic sinus surgery. Our primary goal was to investigate the effects of magnesium sulfate and dexmedetomidine used for controlled hypotension on the visibility of the surgical site. METHODS: 60 patients aged between 18 and 65 years were enrolled. In the magnesium sulfate ...

  9. Methodologies for using stable isotopes to assess magnesium absorption and secretion in children.

    Science.gov (United States)

    Abrams, S A; Wen, J P

    1999-02-01

    To provide methodological information regarding the absorption and excretion of dietary magnesium by children and adolescents. Recently, stable isotope techniques for assessing magnesium absorption and excretion have been developed which allow for these studies to be safely performed in subjects of all ages. In the report, we describe the dosing and sample requirements for such studies. Our data demonstrate that, after oral and intravenous dosing of isotopes, a complete 72-hour urine collection will allow for determination of fractional magnesium absorption. In our study, urinary, but not endogenous fecal magnesium excretion, was closely correlated with magnesium intake (r = 0.47, p = 0.02 vs r = 0.08, p = 0.69). As endogenous fecal magnesium excretion is small relative to urinary magnesium excretion, measurement of endogenous fecal magnesium excretion is not needed to make a reasonable estimate of net magnesium retention for most studies. Using high-precision analytical techniques, an intravenous dose of 25Mg of approximately 0.2 to 0.3 mg/kg would be adequate for absorption measurements. The cost and availability of isotopes and their analysis are such that it should be feasible for increasing numbers of investigators to make use of these techniques.

  10. 21 CFR 862.1495 - Magnesium test system.

    Science.gov (United States)

    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 of magnesium). (b) Classification. Class I. ...

  11. Treatment with magnesium sulphate in pre-term birth

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  12. Transparent thin films of indium tin oxide: Morphology-optical investigations, inter dependence analyzes

    Science.gov (United States)

    Prepelita, P.; Filipescu, M.; Stavarache, I.; Garoi, F.; Craciun, D.

    2017-12-01

    Using a fast and eco-friendly deposition method, ITO thin films with different thicknesses (0.5 μm-0.7 μm) were deposited on glass substrates by radio frequency magnetron sputtering technique. A comparative analysis of these oxide films was then carried out. AFM investigations showed that the deposited films were smooth, uniform and having a surface roughness smaller than 10 nm. X-ray diffraction investigations showed that all samples were polycrystalline and the grain sizes of the films, corresponding to (222) cubic reflection, were found to increase with the increasing film thickness. The optical properties, evaluated by UV-VIS-NIR (190-3000 nm) spectrophotometer, evidenced that the obtained thin films were highly transparent, with a transmission coefficient between 90 and 96%, depending on the film thickness. Various methods (Swanepoel and Drude) were employed to appreciate the optimal behaviour of transparent oxide films, in determining the dielectric optical parameters and refractive index dispersion for ITO films exhibiting interference patterns in the optical transmission spectra. The electrical conductivity also increased as the film thickness increased.

  13. Magnesium for skeletal muscle cramps.

    Science.gov (United States)

    Garrison, Scott R; Allan, G Michael; Sekhon, Ravneet K; Musini, Vijaya M; Khan, Karim M

    2012-09-12

    Skeletal muscle cramps are common and often presented to physicians in association with pregnancy, advanced age, exercise or disorders of the motor neuron (such as amyotrophic lateral sclerosis). Magnesium supplements are marketed for the prophylaxis of cramps but the efficacy of magnesium for this indication has never been evaluated by systematic review. To assess the effects of magnesium supplementation compared to no treatment, placebo control or other cramp therapies in people with skeletal muscle cramps.   We searched the Cochrane Neuromuscular Disease Group Specialized Register (11 October 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (2011, Issue 3), MEDLINE (January 1966 to September 2011), EMBASE (January 1980 to September 2011), LILACS (January 1982 to September 2011), CINAHL Plus (January 1937 to September 2011), AMED (January 1985 to October 2011) and SPORTDiscus (January 1975 to September 2011). Randomized controlled trials (RCTs) of magnesium supplementation (in any form) to prevent skeletal muscle cramps in any patient group (i.e. all clinical presentations of cramp). We considered comparisons of magnesium with no treatment, placebo control, or other therapy. Two authors independently selected trials for inclusion and extracted data. Two authors assessed risk of bias. We attempted to contact all study authors and obtained patient level data for three of the included trials, one of which was unpublished. All data on adverse effects were collected from the included RCTs. We identified seven trials (five parallel, two cross-over) enrolling a total of 406 individuals amongst whom 118 cross-over participants additionally served as their own controls. Three trials enrolled women with pregnancy-associated leg cramps (N = 202) and four trials enrolled idiopathic cramp sufferers (N = 322 including cross-over controls). Magnesium was compared to placebo in six trials and to no treatment in one trial.For idiopathic cramps (largely older

  14. Myth or Reality-Transdermal Magnesium?

    Science.gov (United States)

    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.

  15. Biodegradable magnesium nanoparticle-enhanced laser hyperthermia therapy

    Directory of Open Access Journals (Sweden)

    Wang Q

    2012-08-01

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

  16. Alkoxide-based magnesium electrolyte compositions for magnesium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Sheng; Sun, Xiao-Guang; Liao, Chen; Guo, Bingkun

    2018-01-30

    Alkoxide magnesium halide compounds having the formula: RO--Mg--X (1) wherein R is a saturated or unsaturated hydrocarbon group that is unsubstituted, or alternatively, substituted with one or more heteroatom linkers and/or one or more heteroatom-containing groups comprising at least one heteroatom selected from fluorine, nitrogen, oxygen, sulfur, and silicon; and X is a halide atom. Also described are electrolyte compositions containing a compound of Formula (1) in a suitable polar aprotic or ionic solvent, as well as magnesium batteries in which such electrolytes are incorporated.

  17. Effect of magnesium supplementation on the distribution patterns of zinc, copper, and magnesium in rabbits exposed to prolonged cadmium intoxication.

    Science.gov (United States)

    Bulat, Zorica; Dukić-Ćosić, Danijela; Antonijević, Biljana; Bulat, Petar; Vujanović, Dragana; Buha, Aleksandra; Matović, Vesna

    2012-01-01

    The present study is designed to investigate whether magnesium (Mg) supplementation may prevent Cd-induced alterations in zinc (Zn), copper (Cu), and magnesium (Mg) status in rabbits. For this purpose, the concentrations of Zn, Cu, and Mg were estimated in blood, urine, and organs (brain, heart, lungs, liver, kidney, spleen, pancreas, skeletal muscle, and bone) of rabbits given Cd (10 mg/kg b.w.) and rabbits cotreated with Mg (40 mg/kg b.w.) orally, as aqueous solutions of Cd chloride and Mg acetate every day for 4 weeks. Samples were mineralized with conc. HNO₃ and HClO₄ (4:1) and metals concentrations were determined by atomic absorption spectrophotometry (AAS). Magnesium supplementation succeeded to overcome Cd-induced disbalance of investigated bioelements. Beneficial effects of Mg were observed on Zn levels in blood and urine, on Cu levels in urine, and on Mg levels in blood. Magnesium pretreatment also managed to counteract or reduce all Cd-induced changes in levels of Cu and Mg in organs, while it did not exert this effect on Zn levels. These findings suggest that enhanced dietary Mg intake during Cd exposure can have at least partly beneficial effect on Cd-induced alterations in homeostasis of zinc, copper, and magnesium.

  18. Effect of Magnesium Supplementation on the Distribution Patterns of Zinc, Copper, and Magnesium in Rabbits Exposed to Prolonged Cadmium Intoxication

    Directory of Open Access Journals (Sweden)

    Zorica Bulat

    2012-01-01

    Full Text Available The present study is designed to investigate whether magnesium (Mg supplementation may prevent Cd-induced alterations in zinc (Zn, copper (Cu, and magnesium (Mg status in rabbits. For this purpose, the concentrations of Zn, Cu, and Mg were estimated in blood, urine, and organs (brain, heart, lungs, liver, kidney, spleen, pancreas, skeletal muscle, and bone of rabbits given Cd (10 mg/kg b.w. and rabbits cotreated with Mg (40 mg/kg b.w. orally, as aqueous solutions of Cd chloride and Mg acetate every day for 4 weeks. Samples were mineralized with conc. HNO3 and HClO4 (4:1 and metals concentrations were determined by atomic absorption spectrophotometry (AAS. Magnesium supplementation succeeded to overcome Cd-induced disbalance of investigated bioelements. Beneficial effects of Mg were observed on Zn levels in blood and urine, on Cu levels in urine, and on Mg levels in blood. Magnesium pretreatment also managed to counteract or reduce all Cd-induced changes in levels of Cu and Mg in organs, while it did not exert this effect on Zn levels. These findings suggest that enhanced dietary Mg intake during Cd exposure can have at least partly beneficial effect on Cd-induced alterations in homeostasis of zinc, copper, and magnesium.

  19. The photon energy dependence of the alanine/EPR dosimetry system, an experimental investigation

    International Nuclear Information System (INIS)

    Bergstrand, E.S.; Hole, E.O.; Shortt, K.R.; Ross, C.K.

    2002-01-01

    The energy dependence of a dosimetry system based on electron paramagnetic resonance (EPR) spectroscopy of alanine has been studied to determine its suitability for use in dose verification for radiotherapy. A few experiments with high-energy photon irradiation of alanine have been reported in the literature. However, the reported results disagree whether the ratio of dose in alanine to dose in water is independent of the radiation energy or whether there is a small dependence for photon energies of relevance to radiotherapy. The concentration of free radicals in alanine is proportional to the absorbed dose in alanine over a wide dose range covering three decades. The relative number of radicals may be determined by examining the EPR spectrum, and hence it is possible to determine the dose with a system that has been calibrated using a known dose of 60 Co radiation. In the present work, irradiations of alanine dosimeters were performed at the National Research Council (NRC), in Ottawa, Canada. The radiation qualities investigated were 10, 20 and 30 MV x-rays using the NRC linac. For each radiation quality, 30 dosimeters were irradiated in a water phantom with a level of absorbed dose to water ranging from 10 to 50 Gy. For reference purposes, irradiations using the NRC 60 Co source were performed on more or less the same day as the irradiations at each specific linac quality. In all beams, the dose to water was measured using a graphite-walled NE2571 ionisation chamber that was originally calibrated by comparison with a sealed-water calorimeter. The alanine dosimeters were evaluated at the EPR laboratory at the University of Oslo, Norway, using an X-band Bruker ESP300E spectrometer with a rectangular double resonator. One of the resonators contained a Mn 2+ /MgO sample that was read after each dosimeter reading, in order to provide independence from short-term sensitivity fluctuations in the spectrometer. All dosimeters irradiated at one specific linac quality were

  20. High magnesium mobility in ternary spinel chalcogenides.

    Science.gov (United States)

    Canepa, Pieremanuele; Bo, Shou-Hang; Sai Gautam, Gopalakrishnan; Key, Baris; Richards, William D; Shi, Tan; Tian, Yaosen; Wang, Yan; Li, Juchuan; Ceder, Gerbrand

    2017-11-24

    Magnesium batteries appear a viable alternative to overcome the safety and energy density limitations faced by current lithium-ion technology. The development of a competitive magnesium battery is plagued by the existing notion of poor magnesium mobility in solids. Here we demonstrate by using ab initio calculations, nuclear magnetic resonance, and impedance spectroscopy measurements that substantial magnesium ion mobility can indeed be achieved in close-packed frameworks (~ 0.01-0.1 mS cm -1 at 298 K), specifically in the magnesium scandium selenide spinel. Our theoretical predictions also indicate that high magnesium ion mobility is possible in other chalcogenide spinels, opening the door for the realization of other magnesium solid ionic conductors and the eventual development of an all-solid-state magnesium battery.

  1. Magnesium sulphate for fetal neuroprotection

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  2. Magnesium and related low alloys

    International Nuclear Information System (INIS)

    Bernard, J.; Caillat, R.; Darras, R.

    1959-01-01

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

  3. Corrosion resistance of multilayered magnesium phosphate/magnesium hydroxide film formed on magnesium alloy using steam-curing assisted chemical conversion method

    International Nuclear Information System (INIS)

    Ishizaki, Takahiro; Kudo, Ruriko; Omi, Takeshi; Teshima, Katsuya; Sonoda, Tsutomu; Shigematsu, Ichinori; Sakamoto, Michiru

    2012-01-01

    Anticorrosive multilayered films were successfully prepared on magnesium alloy AZ31 by chemical conversion treatment, followed by steam curing treatment. The crystal structures, chemical composition, surface morphologies, chemical bonding states of the film was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscope (FE-SEM) measurements. All the films had thicknesses of ranging from 24 to 32 μm. The film had two layers that were composed of crystalline NH 4 MgPO 4 ·H 2 O, Mg 2 PO 4 OH·3H 2 O, Mg(OH) 2 and amorphous MgO. The outer layers include magnesium, oxygen, and phosphorous, and the inner layers include magnesium and oxygen. The corrosion resistant performances of the multilayered films in 5 wt% NaCl aqueous solution were investigated by electrochemical and gravimetric measurements. The potentiodynamic polarization curves revealed that the corrosion current density (j corr ) of all the film coated magnesium alloys decreased by more than four orders of magnitude as compared to that of the bare magnesium alloy, indicating that all the films had an inhibiting effect of corrosion reaction. Gravimetric measurements showed that the average corrosion rates obtained from the weight loss rates were estimated to be in the ranges of ca. 0.085–0.129 mm/y. American Society for Testing and Materials (ASTM) standard D 3359-02 cross cut tape test revealed that the adhesion of our anticorrosive multilayered film to the magnesium alloy surface was very good.

  4. Microstructural and technological optimisation of magnesium alloys

    OpenAIRE

    Facchinelli, Nicola

    2013-01-01

    Magnesium is one of the most abundance element in nature, and it's characterised by a lower density than aluminium. These characteristics confer great potential to magnesium alloys, which are so used for specialised applications, like for military purposes and in the aerospace industry. While some magnesium alloys, including the AM60B alloy, are historically associated to high pressure die casting, for such applications the magnesium alloy components are usually produced by the gravity castin...

  5. Solid-state rechargeable magnesium battery

    Science.gov (United States)

    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. Combination of modafinil and d-Amphetamine for the treatment of cocaine dependence: A preliminary investigation

    Directory of Open Access Journals (Sweden)

    Joy M Schmitz

    2012-08-01

    Full Text Available Background: Two stimulant medications, modafinil and d-amphetamine, when tested individually, have shown safety and efficacy for treatment of cocaine addiction. We hypothesized that the combination of modafinil and d-amphetamine, at low doses, would show equivalent or greater benefit in reducing cocaine use compared to higher doses of each individual medication or placebo. Methods: Sixteen week, randomized, parallel-group design with four treatment arms comparing placebo to modafinil 400 mg; d-amphetamine 60 mg; modafinil 200 mg plus d-amphetamine 30 mg. Primary outcome variables, retention and cocaine use, were analyzed on the sample of 73 participants who received the first dose of the study medication. Results: Retention rates did not differ between groups and were generally low, with 40% remaining in treatment at week 12 and 20% at week 16. Participants receiving the combination of modafinil and d-amphetamine showed a trend of increased cocaine use over time with a corresponding low Bayesian probability of benefit (33%. Relatively better cocaine outcomes were observed in the placebo and d-amphetamine only groups. The study medications were generally well-tolerated with few adverse effects, yet rates of adherence were suboptimal (≤ 80%. Conclusion: Data from this preliminary investigation fail to provide evidential support for conducting a larger study of this dual-agonist medication combination for treatment of cocaine dependence.

  7. Leucemia inhibitory factor; investigating the time-dependent effect on viability of vitrified bovine embryos.

    Science.gov (United States)

    Kocyigit, A; Cevik, M

    2017-12-01

    Leucemia inhibitory factor (LIF) is involved in various reproductive processes, including sperm development, regulation of ovulation, as well as blastocyst formation, hatching and implantation in embryos. Moreover, LIF has also been shown significantly to enhance the blastocyst formation rates of bovine embryos, a finding that remains controversial. Our purpose was to investigate time-dependent effect of LIF on bovine embryo culture, especially in terms of addition timing. Presumptive zygotes were cultured in five different groups. In this study, 100 ng/ml LIF was added to the culture medium were as follows; control: SOF alone, group A: at day 0 (fertilization day), group B: at day 4 post-insemination (p.i.), group C: at day 4 to 7 (p.i. before vitrification) and group D: at day 8 (p.i. after thawing). Addition of LIF to the culture medium at day 4 significantly increased the percentage of blastocyst rate when compared day 0, day 4 at 6/7 and control group (41.8% versus 24.3%, 19.7%, 34.6%). In conclusion, the addition of LIF only on day 4 (p.i.) to the culture medium was found to be beneficial for bovine embryonic development based on several measures, including blastocysts rate, re-expansion rate and cellular cryotolerance after vitrification. © 2017 Blackwell Verlag GmbH.

  8. An investigation on the bone density of patients with non-insulin-dependent diabetes mellitus

    International Nuclear Information System (INIS)

    Guo Yan; Huang Zhaomin; Meng Quanfei; Da Rengrong; Zhang Suidong; Weng Jianping

    1999-01-01

    Objective: To investigate the morbidity and pattern of osteoporosis in the patients with non-insulin-dependent diabetes mellitus (NIDDM). Methods: Bone density of lumbar vertebra, hip and whole body were measured in 48 patients with NIDDM and in 35 health people aged 30-35 years. All the patients were diagnosed by the standards introduced by the WHO committee in 1985. Outcome were measured by using t text, analysis of variance and coefficient of multiple correlation. Results: Bone density decreased in all the 48 patients with NIDDM, in which 25 (52.1%) patients were diagnosed as osteoporosis. In the patients with NIDDM and osteoporosis, there was a higher rate of the decrease of the bone density of hip (14.1% in male and 15.6% in female respectively) than that of lumbar vertebra. Conclusions: There is a higher morbidity of osteoporosis in the patients with NIDDM. The loss of the bone density might start at the hip. The bone mineral content of whole body lose markedly. And the longer the NIDDM and the menopause exist, the more obvious the decrease of the bone density is. The mechanism of the phenomena is considered as a result of not only the increased loss of calcium and absorption of the bone tissue induced by the secondary hyperparathyroidism, but also the decreased level of the serum insulin-like growth factor, which inhibits the bone formation

  9. Experimental Investigation of Strain Rate and Temperature Dependent Response of an Epoxy Resin Undergoing Large Deformation

    Science.gov (United States)

    Tamrakar, Sandeep; Ganesh, Raja; Sockalingam, Subramani; Haque, Bazle Z.; Gillespie, John W.

    2018-01-01

    Experimental investigation of the effect of strain rate and temperature on large inelastic deformation of an epoxy resin is presented. Uniaxial compression tests were conducted on DER 353 epoxy resin at strain rates ranging from 0.001 to 12,000/s. Experimental results showed significant rate sensitivity in yield stress, which increased from 85 MPa at 0.001/s to 220 MPa at 12,000/s strain rate. Thermal softening became more prominent as the strain rate was increased, resulting in complete absence of strain hardening at high strain rates. Rise in temperature under high strain rate, due to adiabatic heating, was estimated to increase above glass transition temperature (T g ). A series of compression tests carried out at temperatures ranging from ambient to T g + 80 °C showed yield stress vanishing at T g . Above T g , the epoxy became completely rubbery elastic at quasi-static loading rate. Epoxy became less sensitive to strain rate as the temperature was increased further above T g . The strain rate and temperature dependent yield behavior of the epoxy resin is predicted using Ree-Eyring model.

  10. 21 CFR 582.5431 - Magnesium oxide.

    Science.gov (United States)

    2010-04-01

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

  11. 21 CFR 582.1431 - Magnesium oxide.

    Science.gov (United States)

    2010-04-01

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

  12. EFFECT OF MAGNESIUM SULFATE (A LAXATIVE) ON ...

    African Journals Online (AJOL)

    use with little success . Magnesium sulfate also known as Epsom salt or bitter salt is a hydrate salt with a chemical name of magnesium sulfate heptahydrate . Chemical formula is MgSO. 7HO and trade name is. Andrews liver salt. Dried magnesium sulfate is an osmotic laxative or a saline laxative that acts by increasing the.

  13. 21 CFR 582.5443 - Magnesium sulfate.

    Science.gov (United States)

    2010-04-01

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

  14. 21 CFR 582.5434 - Magnesium phosphate.

    Science.gov (United States)

    2010-04-01

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

  15. Magnesium Diboride Current Leads

    Science.gov (United States)

    Panek, John

    2010-01-01

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

  16. Correlation of magnesium intake with metabolic parameters, depression and physical activity in elderly type 2 diabetes patients: a cross-sectional study

    Science.gov (United States)

    2012-01-01

    Background Type 2 diabetes mellitus is a major global public health problem in the worldwide and is increasing in aging populations. Magnesium intake may be one of the most important factors for diabetes prevention and management. Low magnesium intake may exacerbate metabolic abnormalities. In this study, the relationships of magnesium intake with metabolic parameters, depression and physical activity in elderly patients with type 2 diabetes were investigated. Methods This cross-sectional study involved 210 type 2 diabetes patients aged 65 years and above. Participants were interviewed to obtain information on lifestyle and 24-hour dietary recall. Assessment of depression was based on DSM-IV criteria. Clinical variables measured included anthropometric measurements, blood pressure, and biochemical determinations of blood and urine samples. Linear regression was applied to determine the relationships of magnesium intake with nutritional variables and metabolic parameters. Results Among all patients, 88.6% had magnesium intake which was less than the dietary reference intake, and 37.1% had hypomagnesaemia. Metabolic syndromes and depression were associated with lower magnesium intake (p magnesium intake and HDL-cholesterol (p = 0.005). Magnesium intake was inversely correlated with triglyceride, waist circumference, body fat percent and body mass index (p magnesium intake (p for trend = 0005). Waist circumference, body fat percentage, and body mass index were significantly lower with increase quartile of magnesium intake (p for trend magnesium intake (p for trend magnesium intake was related to high physical activity level and demonstrated lower serum magnesium levels. Serum magnesium was not significantly associated with metabolic parameters. Conclusions The majority of elderly type 2 diabetes who have low magnesium intake may compound this deficiency with metabolic abnormalities and depression. Future studies should determine the effects of

  17. Constraints on Weathering from Riverine Magnesium Isotope Ratios

    DEFF Research Database (Denmark)

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

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

  18. Is magnesium citrate treatment effective on pain, clinical parameters and functional status in patients with fibromyalgia?

    Science.gov (United States)

    Bagis, Selda; Karabiber, Mehmet; As, Ismet; Tamer, Lülüfer; Erdogan, Canan; Atalay, Ayçe

    2013-01-01

    The aims of this study were to investigate the relationship between magnesium levels and fibromyalgia symptoms and to determine the effect of magnesium citrate treatment on these symptoms. Sixty premenopausal women diagnosed with fibromyalgia according to the ACR criteria and 20 healthy women whose age and weight matched the premenopausal women were evaluated. Pain intensity, pain threshold, the number of tender points, the tender point index, the fibromyalgia impact questionnaire (FIQ), the Beck depression and Beck anxiety scores and patient symptoms were evaluated in all the women. Serum and erythrocyte magnesium levels were also measured. The patients were divided into three groups. The magnesium citrate (300 mg/day) was given to the first group (n = 20), amitriptyline (10 mg/day) was given to the second group (n = 20), and magnesium citrate (300 mg/day) + amitriptyline (10 mg/day) treatment was given to the third group (n = 20). All parameters were reevaluated after the 8 weeks of treatment. The serum and erythrocyte magnesium levels were significantly lower in patients with fibromyalgia than in the controls. Also there was a negative correlation between the magnesium levels and fibromyalgia symptoms. The number of tender points, tender point index, FIQ and Beck depression scores decreased significantly with the magnesium citrate treatment. The combined amitriptyline + magnesium citrate treatment proved effective on all parameters except numbness. Low magnesium levels in the erythrocyte might be an etiologic factor on fibromyalgia symptoms. The magnesium citrate treatment was only effective tender points and the intensity of fibromyalgia. However, it was effective on all parameters when used in combination with amitriptyline.

  19. High Dietary Magnesium Intake Is Associated with Low Insulin Resistance in the Newfoundland Population

    Science.gov (United States)

    Shea, Jennifer; Wadden, Danny; Gulliver, Wayne; Randell, Edward; Vasdev, Sudesh; Sun, Guang

    2013-01-01

    Background Magnesium plays a role in glucose and insulin homeostasis and evidence suggests that magnesium intake is associated with insulin resistance (IR). However, data is inconsistent and most studies have not adequately controlled for critical confounding factors. Objective The study investigated the association between magnesium intake and IR in normal-weight (NW), overweight (OW) and obese (OB) along with pre- and post- menopausal women. Design A total of 2295 subjects (590 men and 1705 women) were recruited from the CODING study. Dietary magnesium intake was computed from the Willett Food Frequency Questionnaire (FFQ). Adiposity (NW, OW and OB) was classified by body fat percentage (%BF) measured by Dual-energy X-ray absorptiometry according to the Bray criteria. Multiple regression analyses were used to test adiposity-specific associations of dietary magnesium intake on insulin resistance adjusting for caloric intake, physical activity, medication use and menopausal status. Results Subjects with the highest intakes of dietary magnesium had the lowest levels of circulating insulin, HOMA-IR, and HOMA-ß and subjects with the lowest intake of dietary magnesium had the highest levels of these measures, suggesting a dose effect. Multiple regression analysis revealed a strong inverse association between dietary magnesium with IR. In addition, adiposity and menopausal status were found to be critical factors revealing that the association between dietary magnesium and IR was stronger in OW and OB along with Pre-menopausal women. Conclusion The results of this study indicate that higher dietary magnesium intake is strongly associated with the attenuation of insulin resistance and is more beneficial for overweight and obese individuals in the general population and pre-menopausal women. Moreover, the inverse correlation between insulin resistance and dietary magnesium intake is stronger when adjusting for %BF than BMI. PMID:23472169

  20. A wavelength dependent investigation of the indole photophysics via ionization and fragmentation pump-probe spectroscopies.

    Science.gov (United States)

    Godfrey, T J; Yu, Hui; Biddle, Michael S; Ullrich, Susanne

    2015-10-14

    A wavelength dependent study investigating the low-lying (1)La and (1)Lb states, both possessing (1)ππ* character, and the (1)πσ* state in the deactivation process of indole is presented here. Relaxation dynamics following excitation at 241, 250, 260, 270, 273, and 282 nm are examined using three gas-phase, pump-probe spectroscopic techniques: (1) hydrogen atom (H-atom) time-resolved kinetic energy release (TR-KER), (2) time-resolved photoelectron spectroscopy (TR-PES), and (3) time-resolved ion yield (TR-IY). Applied in combination, a more complete picture of the indole relaxation dynamics may be gleaned. For instance, TR-PES experiments directly observe all relaxation pathways by probing the evolution of the excited states following photoexcitation; whereas, TR-KER measurements indirectly, yet specifically, probe for (1)πσ*-state activity through the detection of H-atoms eliminated along the indole nitrogen-hydrogen (N-H) stretch coordinate-a possible outcome of (1)πσ*-state relaxation in indole. In addition, mass information obtained via TR-IY monitors fragmentation dynamics that may occur within the neutral electronically excited and/or cationic states. The work herein assesses the onset and importance of the (1)πσ* state at various pump wavelengths by systematically tuning across the ultraviolet absorption spectrum of indole with a particular focus on those pump wavelengths longer than 263 nm, where the involvement of the (1)πσ* state is under current debate. As far as this experimental work is concerned, there does not appear to be any significant involvement by the (1)πσ* state in the indole relaxation processes following excitation at 270, 273, or 282 nm. This investigation also evaluates the primary orbital promotions contributing to the (1)La, (1)Lb, and (1)πσ* transitions based on ionization preferences observed in TR-PES spectra. Relaxation time constants associated with dynamics along these states are also reported for excitation at all

  1. An investigation into environment dependent nanomechanical properties of shallow water shrimp (Pandalus platyceros) exoskeleton

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Devendra; Tomar, Vikas, E-mail: tomar@purdue.edu

    2014-11-01

    The present investigation focuses on understanding the influence of change from wet to dry environment on nanomechanical properties of shallow water shrimp exoskeleton. Scanning Electron Microscopy (SEM) based measurements suggest that the shrimp exoskeleton has Bouligand structure, a key characteristic of the crustaceans. As expected, wet samples are found to be softer than dry samples. Reduced modulus values of dry samples are found to be 24.90 ± 1.14 GPa as compared to the corresponding values of 3.79 ± 0.69 GPa in the case of wet samples. Hardness values are found to be 0.86 ± 0.06 GPa in the case of dry samples as compared to the corresponding values of 0.17 ± 0.02 GPa in the case of wet samples. In order to simulate the influence of underwater pressure on the exoskeleton strength, constant load creep experiments as a function of wet and dry environments are performed. The switch in deformation mechanism as a function of environment is explained based on the role played by water molecules in assisting interface slip and increased ductility of matrix material in wet environment in comparison to the dry environment. - Highlights: • Environment dependent (dry-wet) properties of shrimp exoskeleton are analyzed. • Mechanical properties are correlated with the structure and composition. • Presence of water leads to lower reduced modulus and hardness. • SEM images shows the Bouligand pattern based structure. • Creep-relaxation of polymer chains, interface slip is high in presence of water.

  2. Wavelength dependence of laser induced breakdown spectroscopy (LIBS) on questioned document investigation.

    Science.gov (United States)

    Elsherbiny, Nany; Aied Nassef, O

    2015-07-01

    The fast and nearly non-destructive criteria of laser induced breakdown spectroscopy (LIBS) technique has been exploited for forensic purposes, specifically, document investigation. The dependence of the optical emission spectra of different black gel ink samples on the excitation laser wavelength, namely the visible wavelength at λ=532 nm and the IR wavelength at λ=1064 nm, was studied. The inks of thirty black gel-ink pens comprising ten brands were analyzed to determine the variation of the chemical composition of ink and to discriminate among them with minimum mass removal and minimum damage to the document's paper. Under the adopted experimental conditions, the ability of the visible LIBS to differentiate among the different ink samples was successful compared to IR LIBS at the same laser pulse energy (~25 mJ/pulse, laser fluence is ~1400J·cm(-2) for visible laser and ~1100J·cm(-2) for IR laser) which could be attributed to the IR absorption effects by the black ink. However, the visible LIBS produces deeper crater with respect to that produced by IR LIBS. Applying IR LIBS with higher pulse energy of ~87mJ (laser fluence is ~4100J·cm(-2)), identification and differentiation of the adopted samples was performed with producing a larger-diameter but superficial crater. The plasma parameters are discussed at the adopted experimental conditions. The results support the potential of LIBS technique using both the visible and IR lasers to be commercially developed for forensic document examination. Copyright © 2015 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  3. Hydrogen Sorption Performance of Pure Magnesium during Continued Cycling

    DEFF Research Database (Denmark)

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

    1983-01-01

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

  4. Effect of anhydrous magnesium sulphate fertilizer and cutting ...

    African Journals Online (AJOL)

    Effect of anhydrous magnesium sulphate fertilizer on Panicum maximum yield and chemical composition of the resultant herbage harvested at 3, 4 and 5 weeks of age was investigated. The treatments were labeled T1 to T6. T1 was fertilized and harvested at 3 weeks cutting interval, T2 was fertilized and harvested at 4 ...

  5. Magnesium Trimethoxyphenylporphyrin Chain Controls Energy ...

    Indian Academy of Sciences (India)

    chemsci

    The green pigment chlorophyll present in green leaves initiates the photosynthesis. Chlorophyll is a porphyrin- type tetrapyrrolic macrocyclic molecule with a reduced double bond in one of the pyrrole rings. The metal present in chlorophyll is magnesium; however, some zinc containing bacteriochlorophylls are also known.

  6. Utilization of magnesium during hypokinesia and magnesium supplementation in healthy subjects.

    Science.gov (United States)

    Zorbas, Yan G; Kakuris, Kostas K; Federenko, Yuri F; Deogenov, Viktor A

    2010-01-01

    The incompleteness of electrolyte utilization during hypokinesia and electrolyte supplementation is the defining factor of electrolyte metabolic changes, yet the effect of electrolyte supplementation and HK upon electrolyte utilization is poorly understood. To determine the influence of magnesium (Mg(2+)) supplementation and hypokinesia (diminished movement) on magnesium utilization, we investigated the use of Mg(2+) supplementation to establish its effect upon muscle Mg(2+) content and Mg2(2+) losses. This study was conducted in 40 physically healthy male volunteers during a pre-experimental period of 30 d and an experimental period of 364 d. Subjects were equally divided into four groups: unsupplemented control subjects (UCSs), unsupplemented experimental subjects (UESs), supplemented control subjects (SCSs), and supplemented experimental subjects (SESs). A daily supplementation of 3.0 mmol of magnesium-chloride per kilogram of body weight was given to subjects in the SCS and SES groups. Muscle Mg(2+) content decreased (P urine and feces increased (P urine and feces increased more (P < 0.05) in the SES group than in the UES group.The muscle Mg(2+) content and plasma Mg(2+) level and Mg(2+) losses did not change in the control groups. Daily Mg(2+) supplementation during prolonged hypokinesia decreases more muscle Mg(2+) content and Mg(2+)-deficient muscle increases more Mg(2+) loss in healthy subjects indicating lower Mg(2+) utilization with than without Mg(2+) supplementation. Copyright © 2010 Elsevier Inc. All rights reserved.

  7. Investigations on hormone dependency of human mammary carcinomas transplanted into nude mice

    DEFF Research Database (Denmark)

    Brünner, N; Spang-Thomsen, M

    1981-01-01

    Since human mammary cancer can be transplanted into nude mice, this makes possible the in vivo study of relations between hormone dependency and the steroid hormone receptor content of the tumors. The macroscopic growth curve of the transplanted tumors during endocrine therapy will reflect...... the hormone dependency. The results can be compared with successive steroid hormone receptor determinations in the tumor tissue....

  8. Purification of Food-grade Magnesium Chloride

    Directory of Open Access Journals (Sweden)

    Ji Lianmin

    2016-01-01

    Full Text Available The application of the varying weights of bischofite dissolved in the distilled water was investigated. The effects of the temperature on the rate of evaporation and the thermal precipitation time on the purity of the crystal products were fully investigated. Two validation tests including magnifying tests and recycling residue were also studied. Our results demonstrate that the contents of NaCl, KCl and CaSO4in the filtrate reached a minimum value after the pretreatment of 350 g bischofite dissolved in 100 mldistilled water. In the crystal products from the second evaporating stage of the validation tests, the contents of MgCl2·6H2O, SO4 and NaCl+KCl are 99%, ≤0.1±0.01%and ≤0.8±0.04%, respectively. The content of magnesium chloride in the solution was increased to a greater extent, and the impurities reduced correspondingly through thedissolution pretreatments of bischofite. This could decrease energy consumption for the impurity removing stage, evaporation and crystallization process, and thus reduce costs for the industrial production of food-grade magnesium chloride

  9. Corrosion and hydrogen permeation of A216 Grade WCA steel in hydrothermal magnesium-containing brines

    International Nuclear Information System (INIS)

    Haberman, J.H.; Frydrych, D.J.; Westerman, R.E.

    1988-03-01

    Corrosion rates determined at 1 month in 150/degree/C brine increased with magnesium concentration. The structure of the corrosion product, as determined by x-ray diffraction, depended upon the magnesium concentration. In brines with less than 10,000 ppM magnesium, the primary corrosion product had a spinel structure characteristic of magnetite or magnesioferrite. In brines containing magnesium concentrations greater than 20,000 ppM, the primary corrosion product had the amakinite structure characteristic of a complex iron-magnesium hydroxide. The high corrosion rates observed in brines containing high magnesium concentrations suggest that the corrosion products having the amakinite structure is less protective than corrosion products having the spinel structure. Corrosion rates in high-magnesium (inclusion) brine determined over a 6-month test duration were essentially constant. Hydrogen permeation rates observed in exposing mild steel to high-Mg/sup 2/plus// brine at 150/degree/C could be potentially damaging to a mild steel waste package container. The rate of hydrogen permeation was proportional to the brine flow rate in the autoclave. Thiourea additions to the brine increased the hydrogen permeation rate; sulfate and bromide ion additions did not. The maximum gaseous hydrogen pressure attainable is not known (based on 3Fe /plus/ 4H 2 O /plus/ Fe(sub 3)O /plus/ 4H 2 , would be /approximately/900 atmospheres), and the dependence of permeation rate on temperature is not known. 8 refs., 13 figs., 3 tabs

  10. A comparative study of the ignition and burning characteristics of after burning aluminum and magnesium particles

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ji Hwan; Lee, Sang Hyup; Yoon, Woong Sup [Yonsei University, Seoul (Korea, Republic of)

    2014-10-15

    Ignition and the burning of air-born single aluminum and magnesium particles are experimentally investigated. Particles of 30 to 106 μm-diameters were electrodynamically levitated, ignited, and burnt in atmospheric air. The particle combustion evolution was recorded by high-speed cinematography. Instant temperature and thermal radiation intensity were measured using two-wavelength pyrometry and photomultiplier tube methods. Ignition of the magnesium particle is prompt and substantially advances the aluminum particle by 10 ms. Burning time of the aluminum particles is extended 3 to 5 times longer than the magnesium particles. Exponents of a power-law fit of the burning rates are 1.55 and 1.24 for aluminum and magnesium particles, respectively. Flame temperature is slightly lower than the oxide melting temperature. For the aluminum, dimensionless flame diameter is inert to the initial particle size, but for the magnesium inversely proportional to the initial diameter.

  11. A comparative study of the ignition and burning characteristics of after burning aluminum and magnesium particles

    International Nuclear Information System (INIS)

    Lim, Ji Hwan; Lee, Sang Hyup; Yoon, Woong Sup

    2014-01-01

    Ignition and the burning of air-born single aluminum and magnesium particles are experimentally investigated. Particles of 30 to 106 μm-diameters were electrodynamically levitated, ignited, and burnt in atmospheric air. The particle combustion evolution was recorded by high-speed cinematography. Instant temperature and thermal radiation intensity were measured using two-wavelength pyrometry and photomultiplier tube methods. Ignition of the magnesium particle is prompt and substantially advances the aluminum particle by 10 ms. Burning time of the aluminum particles is extended 3 to 5 times longer than the magnesium particles. Exponents of a power-law fit of the burning rates are 1.55 and 1.24 for aluminum and magnesium particles, respectively. Flame temperature is slightly lower than the oxide melting temperature. For the aluminum, dimensionless flame diameter is inert to the initial particle size, but for the magnesium inversely proportional to the initial diameter.

  12. A SEARCH FOR MAGNESIUM IN EUROPA'S ATMOSPHERE

    International Nuclear Information System (INIS)

    Hörst, S. M.; Brown, M. E.

    2013-01-01

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

  13. Synthesis and characterization of magnesium gluconate contained poly(lactic-co-glycolic acid)/chitosan microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Shekh M. [Department of Chemical, Biological and Bioengineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Mahoney, Christopher [Department of Bioengineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, PA 15250 (United States); Sankar, Jagannathan [NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Department of Mechanical Engineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); Marra, Kacey G. [NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Department of Bioengineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, PA 15250 (United States); Department of Plastic Surgery, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15250 (United States); McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA 15250 (United States); Bhattarai, Narayan, E-mail: nbhattar@ncat.edu [Department of Chemical, Biological and Bioengineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States)

    2016-01-15

    Graphical abstract: - Highlights: • Magnesium gluconate contained PLGA/chitosan microspheres were fabricated. • In vitro release of magnesium ions was performed using Xylidyl Blue assay. • Chitosan coated PLGA can significantly control the release of magnesium ions. • Cellular compatibility was tested using adipose-derived stem cells and PC12 cells. • The cells encounter acceptably low levels of damage in contact with microspheres. - Abstract: The goal of this study was to fabricate and investigate the chitosan coated poly(lactic-co-glycolic acid) (PLGA) microspheres for the development of controlled release magnesium delivery system. PLGA based microspheres are ideal vehicles for many controlled release drug delivery applications. Chitosan is a naturally occurring biodegradable and biocompatible polysaccharide, which can coat the surface of PLGA to alter the release of drugs. Magnesium gluconate (MgG) was encapsulated in the PLGA and PLGA/chitosan microspheres by utilizing the double emulsion solvent evaporation technique for controlled release study. The microspheres were tested with respect to several physicochemical and biological properties, including morphology, chemical structure, chitosan adsorption efficiency, magnesium encapsulation efficiency, in vitro release of magnesium ions, and cellular compatibility using both human adipose-derived stem cells (ASCs) and PC12 cells. Chitosan coated PLGA microspheres can significantly control the release of magnesium ions compared to uncoated PLGA microspheres. Both coated and uncoated microspheres showed good cellular compatibility.

  14. On the effect of interaction of molybdenum trioxide and magnesium oxide in water

    International Nuclear Information System (INIS)

    Bunin, V.M.; Karelin, A.I.; Solov'eva, L.N.

    1992-01-01

    Interaction of molybdenum trioxide and magnesium oxide in water was studied. It is shown that molybdenum trioxide forms consecutively magnesium molybdate, dimolybdate and magnesium polymolybdates with magnesium oxide

  15. Time-Dependent Damage Investigation of Rock Mass in an In Situ Experimental Tunnel

    Science.gov (United States)

    Jiang, Quan; Cui, Jie; Chen, Jing

    2012-01-01

    In underground tunnels or caverns, time-dependent deformation or failure of rock mass, such as extending cracks, gradual rock falls, etc., are a costly irritant and a major safety concern if the time-dependent damage of surrounding rock is serious. To understand the damage evolution of rock mass in underground engineering, an in situ experimental testing was carried out in a large belowground tunnel with a scale of 28.5 m in width, 21 m in height and 352 m in length. The time-dependent damage of rock mass was detected in succession by an ultrasonic wave test after excavation. The testing results showed that the time-dependent damage of rock mass could last a long time, i.e., nearly 30 days. Regression analysis of damage factors defined by wave velocity, resulted in the time-dependent evolutional damage equation of rock mass, which corresponded with logarithmic format. A damage viscoelastic-plastic model was developed to describe the exposed time-dependent deterioration of rock mass by field test, such as convergence of time-dependent damage, deterioration of elastic modules and logarithmic format of damage factor. Furthermore, the remedial measures for damaged surrounding rock were discussed based on the measured results and the conception of damage compensation, which provides new clues for underground engineering design.

  16. Chemopreventive Effects of Magnesium Chloride Supplementation on Hormone Independent Prostate Cancer Cells

    Directory of Open Access Journals (Sweden)

    Elsa Quiroz

    2016-01-01

    Full Text Available Background: Lifestyle significantly impacts the risk factors associated with prostate cancer, out of which diet appears to be the most influential. An emerging chemopreventive approach, which involves the adequate intake of dietary constituents, has shown great potential in preventing the occurrence or progression of cancer. Magnesium is known to be an essential cofactor for more than 300 enzymatic processes, and is responsible for the regulation of various cellular reactions in the body. A plethora of studies have shown evidence that changes in the intracellular levels of magnesium could contribute to cell proliferation and apoptosis in some normal and malignant cells. The aim of the study was to investigate the effects of magnesium chloride (MgCl2 in DU-145 prostate cancer cells. Methodology: Cultured DU-145 cells were subjected to graded concentrations or doses (50-500 µM of MgCl2 for 48 hours. The cell viability was assessed using MTT and Resazurin reduction assays. NBT assay was also used to assess the treatment-induced intracellular ROS levels. Acridine Orange/Ethidium Bromide (AcrO/EtBr and Rh123/EtBr fluorescent stains were used to assess the cell death type and mitochondrial membrane potential (Δψm respectively. Results: The results revealed a dose-dependent decrease (P < 0.05 in cell viability in treated DU-145 cells after 48 hours. The NBT assay also revealed a dose dependent biphasic response (P < 0.05 in intracellular levels of ROS. There was a drop (P < 0.05 in ROS levels in all groups except at 100 µM, where ROS level was higher than the control. Apoptosis was the primary mode of cell death as observed in the fluorescence analysis. Conclusion: Our finding suggests that MgCl2 may be potentially chemopreventive for prostate cancer. This justifies further studies into its mechanism of action in DU-145 and other prostate cancer cell types.

  17. Level of khat dependence, use patterns, and psychosocial correlates in Yemen: a cross-sectional investigation.

    Science.gov (United States)

    Nakajima, Motohiro; Hoffman, Richard; al'Absi, Mustafa

    2017-05-01

    Chronic khat use is associated with negative health consequences. However, no study has fully characterized individuals who are khat dependent. This paper examines socio-demographic and psychosocial correlates of adult khat dependence. A total of 270 khat users (129 women) in Yemen completed face-to-face interviews and provided demographic information and data on patterns of khat use, subjective mood, and sleep quality. The Severity of Dependence Scale-Khat (SDS-khat) was used to assess level of khat dependence. A series of analysis of variance was conducted. Khat users, on average, used khat for 5.2 hours a day (SD = 2.3) for 5.7 days a week (SD = 2.0). Individuals who screened positive for khat dependence reported longer duration of khat sessions per day, higher frequency of khat use per week, greater levels of negative mood and sleep disturbances, and were more likely to endorse physical symptoms after khat use (P < 0.05). Future research should elucidate mechanisms responsible for khat dependence symptomatology.

  18. Effect of magnesium treatment and glucose levels on delayed cerebral ischemia in patients with subarachnoid hemorrhage: a substudy of the Magnesium in Aneurysmal Subarachnoid Haemorrhage trial (MASH-II).

    Science.gov (United States)

    Leijenaar, Jolien F; Dorhout Mees, Sanne M; Algra, Ale; van den Bergh, Walter M; Rinkel, Gabriel J E

    2015-10-01

    Magnesium treatment did not improve outcome in patients with aneurysmal subarachnoid haemorrhage in the Magnesium in Aneurysmal Subarachnoid Haemorrhage II trial. We hypothesized that high glucose levels may have offset a potential beneficial effect to prevent delayed cerebral ischemia. We investigated if magnesium treatment led to less delayed cerebral ischemia and if glucose levels interacted with magnesium treatment in the Magnesium in Aneurysmal Subarachnoid Haemorrhage II trial. To investigate the effect of magnesium treatment on occurrence of delayed cerebral ischemia and the interaction between glucose levels and magnesium treatment in subarachnoid hemorrhage patients. The Magnesium in Aneurysmal Subarachnoid Haemorrhage was a phase III randomized placebo-controlled trial assessing the effect of magnesium sulphate on clinical outcome in aneurysmal subarachnoid hemorrhage patients. For the current study, we included only the patients admitted to the University Medical Centre-Utrecht. We calculated hazard ratios for occurrence of delayed cerebral ischemia in patients treated with magnesium vs. placebo for the entire study population, and separately in the subgroups of patients with high and low mean fasting and mean daily glucose levels until onset of delayed cerebral ischemia. We used the cross-product of magnesium and glucose in the regression analysis to evaluate whether an interaction between magnesium and glucose existed. We included 616 patients: 307 received magnesium and 309 placebo; 156 patients had delayed cerebral ischemia. Hazard ratio for magnesium on occurrence of delayed cerebral ischemia was 1·0 (95% confidence interval: 0·7-1·4). Results were similar in patients with low or high fasting or daily glucose levels. We found no interactions between magnesium treatment and high fasting (P = 0·54) and daily glucose (P = 0·60). Magnesium treatment did not reduce the risk of delayed cerebral ischemia in patients with aneurysmal

  19. Experimental Investigation of the Corrosion Behavior of Friction Stir Welded AZ61A Magnesium Alloy Welds under Salt Spray Corrosion Test and Galvanic Corrosion Test Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    A. Dhanapal

    2013-01-01

    Full Text Available Extruded Mg alloy plates of 6 mm thick of AZ61A grade were butt welded using advanced welding process and friction stir welding (FSW processes. The specimens were exposed to salt spray conditions and immersion conditions to characterize their corrosion rates on the effect of pH value, chloride ion concentration, and corrosion time. In addition, an attempt was made to develop an empirical relationship to predict the corrosion rate of FSW welds in salt spray corrosion test and galvanic corrosion test using design of experiments. The corrosion morphology and the pit morphology were analyzed by optical microscopy, and the corrosion products were examined using scanning electron microscope and X-ray diffraction analysis. From this research work, it is found that, in both corrosion tests, the corrosion rate decreases with the increase in pH value, the decrease in chloride ion concentration, and a higher corrosion time. The results show the usage of the magnesium alloy for best environments and suitable applications from the aforementioned conditions. Also, it is found that AZ61A magnesium alloy welds possess low-corrosion rate and higher-corrosion resistance in the galvanic corrosion test than in the salt spray corrosion test.

  20. Thermochemistry of dense hydrous magnesium silicates

    Science.gov (United States)

    Bose, Kunal; Burnley, Pamela; Navrotsky, Alexandra

    1994-01-01

    Recent experimental investigations under mantle conditions have identified a suite of dense hydrous magnesium silicate (DHMS) phases that could be conduits to transport water to at least the 660 km discontinuity via mature, relatively cold, subducting slabs. Water released from successive dehydration of these phases during subduction could be responsible for deep focus earthquakes, mantle metasomatism and a host of other physico-chemical processes central to our understanding of the earth's deep interior. In order to construct a thermodynamic data base that can delineate and predict the stability ranges for DHMS phases, reliable thermochemical and thermophysical data are required. One of the major obstacles in calorimetric studies of phases synthesized under high pressure conditions has been limitation due to the small (less than 5 mg) sample mass. Our refinement of calorimeter techniques now allow precise determination of enthalpies of solution of less than 5 mg samples of hydrous magnesium silicates. For example, high temperature solution calorimetry of natural talc (Mg(0.99) Fe(0.01)Si4O10(OH)2), periclase (MgO) and quartz (SiO2) yield enthalpies of drop solution at 1044 K to be 592.2 (2.2), 52.01 (0.12) and 45.76 (0.4) kJ/mol respectively. The corresponding enthalpy of formation from oxides at 298 K for talc is minus 5908.2 kJ/mol agreeing within 0.1 percent to literature values.

  1. Reversibility and Viscoelastic Properties of Micropillar Supported and Oriented Magnesium Bundled F-Actin.

    Directory of Open Access Journals (Sweden)

    Timo Maier

    Full Text Available Filamentous actin is one of the most important cytoskeletal elements. Not only is it responsible for the elastic properties of many cell types, but it also plays a vital role in cellular adhesion and motility. Understanding the bundling kinetics of actin filaments is important in the formation of various cytoskeletal structures, such as filopodia and stress fibers. Utilizing a unique pillar-structured microfluidic device, we investigated the time dependence of bundling kinetics of pillar supported free-standing actin filaments. Microparticles attached to the filaments allowed the measurement of thermal motion, and we found that bundling takes place at lower concentrations than previously found in 3-dimensional actin gels, i.e. actin filaments formed bundles in the presence of 5-12 mM of magnesium chloride in a time-dependent manner. The filaments also displayed long term stability for up to hours after removing the magnesium ions from the buffer, which suggests that there is an extensive hysteresis between cation induced crosslinking and decrosslinking.

  2. Dietary magnesium deficiency affects gut microbiota and anxiety-like behaviour in C57BL/6N mice.

    Science.gov (United States)

    Pyndt Jørgensen, Bettina; Winther, Gudrun; Kihl, Pernille; Nielsen, Dennis S; Wegener, Gregers; Hansen, Axel K; Sørensen, Dorte B

    2015-10-01

    Magnesium deficiency has been associated with anxiety in humans, and rodent studies have demonstrated the gut microbiota to impact behaviour. We investigated the impact of 6 weeks of dietary magnesium deficiency on gut microbiota composition and anxiety-like behaviour and whether there was a link between the two. A total of 20 C57BL/6 mice, fed either a standard diet or a magnesium-deficient diet for 6 weeks, were tested using the light-dark box anxiety test. Gut microbiota composition was analysed by denaturation gradient gel electrophoresis. We demonstrated that the gut microbiota composition correlated significantly with the behaviour of dietary unchallenged mice. A magnesium-deficient diet altered the gut microbiota, and was associated with altered anxiety-like behaviour, measured by decreased latency to enter the light box. Magnesium deficiency altered behavior. The duration of magnesium deficiency is suggested to influence behaviour in the evaluated test.

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

    Directory of Open Access Journals (Sweden)

    Zhiping Wu

    2014-01-01

    Full Text Available The effect of ultrafine magnesium hydroxide (UMH and ordinary magnesium hydroxide (OMH on the tensile properties and flame retardancy of wood plastic composites (WPC were investigated by tensile test, oxygen index tester, cone calorimeter test, and thermogravimetric analysis. The results showed that ultrafine magnesium hydroxide possesses strengthening and toughening effect of WPC. Scanning electron micrograph (SEM of fracture section of samples provided the positive evidence that the tensile properties of UMH/WPC are superior to that of WPC and OMH/WPC. The limited oxygen index (LOI and cone calorimeter test illustrated that ultrafine magnesium hydroxide has stronger flame retardancy and smoke suppression effect of WPC compared to that of ordinary magnesium hydroxide. The results of thermogravimetric analysis implied that ultrafine magnesium hydroxide can improve the char structure which plays an important role in reducing the degradation speed of the inner matrix during combustion process and increases the char residue at high temperature.

  4. Suppression of cortical spreading depressions after magnesium treatment in the rat

    NARCIS (Netherlands)

    van der Hel, W S; van den Bergh, W M; Nicolay, K; Tulleken, K A; Dijkhuizen, R M

    1998-01-01

    The aim of this study was to investigate whether the neuroprotective properties of magnesium in cerebral ischaemia involve suppression of repetitive tissue depolarizations. Cortical spreading depressions (CSDs), evoked by cortical KCl application, and cardiac arrest-induced anoxic depolarization

  5. Effects of segregation of primary alloying elements on the creep response in magnesium alloys

    DEFF Research Database (Denmark)

    Huang, Y.D.; Dieringa, H.; Hort, N.

    2008-01-01

    The segregation of primary alloying elements deteriorates the high temperature creep resistance of magnesium alloys. Annealing at high temperatures alleviating their segregations can improve the creep resistance. Present investigation on the effect of segregation of primary alloying elements on t...

  6. Spectrographic determination of impurities in magnesium metal

    International Nuclear Information System (INIS)

    Capdevila, C.; Diaz-Guerra, J. P.

    1979-01-01

    The spectrographic determination of trace quantities of Al, B, Cd, Co, Cr, Cu, Fe, Li, Hn, Mo, Ni and Si in magnesium metal is described. Samples are dissolved with HNO 3 and calcinate into MgO. In order to avoid losses of boron NH 4 OH is added to the nitric solution. Except for aluminium and chromium the analysis is performed through the use of the carrier distillation technique. These two impurities are determined by burning to completion the MgO. Among the compounds studied as carriers (AgCl, AgF, CsCl, CuF 2 , KCl and SrF 2 ) AgCl allows, In general, the best volatilization efficiency. Lithium determination is achieved by using KC1 or CsCl. Detection limits, on the basis of MgO, are in the range 0,1 to 30 ppm, depending on the element. (Author) 8 refs

  7. [Magnesium sulphate for the management of preeclampsia].

    Science.gov (United States)

    Rozenberg, P

    2006-01-01

    In case of eclampsia, and especially in case of preeclampsia, no consensus exist in order to treat or to prevent convulsions by routine use of magnesium sulphate, at least in France. However, a large, multicentre, randomised trial compared the efficacy of magnesium sulphate with diazepam or phenytoin in eclamptic women. In this trial, magnesium sulphate was associated with a significantly lower rate of recurrent seizures and lower rate of maternal death than that observed with other anticonvulsants. The primary objective of magnesium sulphate prophylaxis in women with preeclampsia is to prevent or reduce the rate of eclampsia and complications associated with eclampsia. There are 3 large randomised controlled trials comparing the use of magnesium sulphate to prevent convulsions in patients with severe preeclampsia: the first one was vs phenytoin, the second vs placebo, and the third vs nimodipine. Patients receiving magnesium sulphate presented a significant lower risk of eclampsia than that observed with other comparison groups, probably by decreasing the cerebral perfusion pressure, thus avoiding a cerebral barotrauma. However, several arguments balance a wide use of magnesium sulphate: the prevalence of eclampsia in the Western world is very low, the use of magnesium sulphate does not affect the neonatal morbidity and mortality, and it is associated with a high rate of side effects, sometimes severe, such as respiratory depression. Thus, the benefit to risk ratio has to guide the use of magnesium sulphate and is directly correlated to the prevalence of eclampsia according to the risk of considered group. 1) The rate of seizures in women with mild preeclampsia not receiving magnesium sulphate is very low. Magnesium sulphate may potentially be associated with a higher number of adverse maternal effects. Therefore, the benefit to risk ratio does not support routine use of magnesium sulphate prophylaxis in this group. 2) On the other hand, the higher rate of

  8. Optical Orientation and Inverse Spin Hall Effect as Effective Tools to Investigate Spin-Dependent Diffusion

    Directory of Open Access Journals (Sweden)

    Marco Finazzi

    2016-11-01

    Full Text Available In this work we address optical orientation, a process consisting in the excitation of spin polarized electrons across the gap of a semiconductor. We show that the combination of optical orientation with spin-dependent scattering leading to the inverse spin-Hall effect, i.e., to the conversion of a spin current into an electrical signal, represents a powerful tool to generate and detect spin currents in solids. We consider a few examples where these two phenomena together allow addressing the spin-dependent transport properties across homogeneous samples or metal/semiconductor Schottky junctions.

  9. Synthesis of nano-sized MgO particle and thin film from diethanolamine-stabilized magnesium-methoxide

    International Nuclear Information System (INIS)

    Jung, Hyun Suk; Lee, J.-K.; Young Kim, J.; Hong, Kug Sun

    2003-01-01

    The effects of diethanolamine (DEA) addition on the crystallization behavior of magnesium methoxide and the stabilization behavior of the Mg-alkoxide were investigated using differential scanning calorimetry, thermogravimetry, X-ray powder diffraction, transmission electron microscopy, and X-ray photoemission spectroscopy. 20 mol% DEA additions to magnesium methoxide showed enhanced stability such that a time-dependent change in the sol was not observed in air. Moreover, the DEA addition enhanced the crystallization process. Crystalline MgO in the 20 mol% of DEA-added magnesium methoxide powder was observed at 300 deg. C for samples processed in O 2 and a high degree of crystallinity was observed at 400 deg. C when processed in O 2 . The enhanced crystallization of Mg-methoxide with added DEA in O 2 is discussed in terms of structural relaxation and heat generation during the ignition of an organic species of DEA. Using a DEA added sol, a MgO thin film with a high degree of crystallinity was prepared at 400 deg. C in O 2

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

    International Nuclear Information System (INIS)

    Wang Qiang; Tan Lili; Xu Wenli; Zhang Bingchun; Yang Ke

    2011-01-01

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

  11. Preparation and corrosion resistance of magnesium phytic acid/hydroxyapatite composite coatings on biodegradable AZ31 magnesium alloy.

    Science.gov (United States)

    Zhang, Min; Cai, Shu; Zhang, Feiyang; Xu, Guohua; Wang, Fengwu; Yu, Nian; Wu, Xiaodong

    2017-06-01

    In this work, a magnesium phytic acid/hydroxyapatite composite coating was successfully prepared on AZ31 magnesium alloy substrate by chemical conversion deposition technology with the aim of improving its corrosion resistance and bioactivity. The influence of hydroxyapatite (HA) content on the microstructure and corrosion resistance of the coatings was investigated. The results showed that with the increase of HA content in phytic acid solution, the cracks on the surface of the coatings gradually reduced, which subsequently improved the corrosion resistance of these coated magnesium alloy. Electrochemical measurements in simulated body fluid (SBF) revealed that the composite coating with 45 wt.% HA addition exhibited superior surface integrity and significantly improved corrosion resistance compared with the single phytic acid conversion coating. The results of the immersion test in SBF showed that the composite coating could provide more effective protection for magnesium alloy substrate than that of the single phytic acid coating and showed good bioactivity. Magnesium phytic acid/hydroxyapatite composite, with the desired bioactivity, can be synthesized through chemical conversion deposition technology as protective coatings for surface modification of the biodegradable magnesium alloy implants. The design idea of the new type of biomaterial is belong to the concept of "third generation biomaterial". Corrosion behavior and bioactivity of coated magnesium alloy are the key issues during implantation. In this study, preparation and corrosion behavior of magnesium phytic acid/hydroxyapatite composite coatings on magnesium alloy were studied. The basic findings and significance of this paper are as follows: 1. A novel environmentally friendly, homogenous and crack-free magnesium phytic acid/hydroxyapatite composite coating was fabricated on AZ31 magnesium alloy via chemical conversion deposition technology with the aim of enhancing its corrosion resistance and

  12. Investigation of the pressure dependence of the Gibbs potential for polymer blends by means of SANS

    DEFF Research Database (Denmark)

    Janssen, S.; Schwahn, D.; Springer, T.

    1995-01-01

    The temperature and pressure dependence of the Flory-Huggins parameter was determined for several polymer blends from the SANS structure factor S(Q --> 0) for pressures less than or equal to 1.2 kbar. It can be split into an enthalpic and an entropic part. Furthermore, the radius of gyration...

  13. Investigations on hormone dependency of human mammary carcinomas transplanted into nude mice

    DEFF Research Database (Denmark)

    Brünner, N; Spang-Thomsen, M

    1981-01-01

    Since human mammary cancer can be transplanted into nude mice, this makes possible the in vivo study of relations between hormone dependency and the steroid hormone receptor content of the tumors. The macroscopic growth curve of the transplanted tumors during endocrine therapy will reflect...

  14. Investigation of a growth model incorporating density dependence for the mackerel management plan simulations

    NARCIS (Netherlands)

    Brunel, T.P.A.

    2015-01-01

    This report presents a framework to model density dependent growth for the North East Atlantic mackerel. The model used is the classical von Bertalanffy equation, but modified so that growth is reduced when stock size increases. The model developed was able to reproduce quite closely the trends in

  15. Calcium and magnesium silicate hydrates

    International Nuclear Information System (INIS)

    Lothenbach, B.; L'Hopital, E.; Nied, D.; Achiedo, G.; Dauzeres, A.

    2015-01-01

    Deep geological disposals are planed to discard long-lived intermediate-level and high-level radioactive wastes. Clay-based geological barriers are expected to limit the ingress of groundwater and to reduce the mobility of radioelements. In the interaction zone between the cement and the clay based material alteration can occur. Magnesium silicate hydrates (M-S-H) have been observed due to the reaction of magnesium sulfate containing groundwater with cements or in the interaction zone between low-pH type cement and clays. M-S-H samples synthesized in the laboratory showed that M-S-H has a variable composition within 0.7 ≤ Mg/Si ≤ 1.5. TEM/EDS analyses show an homogeneous gel with no defined structure. IR and 29 Si NMR data reveal a higher polymerization degree of the silica network in M-S-H compared to calcium silicate hydrates (C-S-H). The presence of mainly Q 3 silicate tetrahedrons in M-S-H indicates a sheet like or a triple-chain silica structure while C-S-H is characterised by single chain-structure. The clear difference in the silica structure and the larger ionic radius of Ca 2+ (1.1 Angstrom) compared to Mg 2+ (0.8 Angstrom) make the formation of an extended solid solution between M-S-H and C-S-H gel improbable. In fact, the analyses of synthetic samples containing both magnesium and calcium in various ratios indicate the formation of separate M-S-H and C-S-H gels with no or very little uptake of magnesium in CS-H or calcium in M-S-H

  16. Crystal plasticity based finite element modelling of large strain deformation in AM30 magnesium alloy

    Science.gov (United States)

    Izadbakhsh, Adel; Inal, Kaan; Mishra, Raja K.

    2012-04-01

    In this paper, the finite strain plastic deformation of AM30 magnesium alloy has been simulated using the crystal plasticity finite element method. The simulations have been carried out using a rate-dependent elastic-viscoplastic crystal plasticity constitutive model implemented in a user defined material subroutine (UMAT) in the commercial software LS-DYNA. The plastic deformation mechanisms accounted for in the model are the slip systems in the matrix (parent grain), extension twinning systems and the slip systems inside the extension twinned regions. The parameters of the constitutive model have been calibrated using the experimental data. The calibrated model has then been used to predict the deformation of AM30 magnesium alloy in bending and simple shear. For the bending strain path, the effects of texture on the strain accommodated by the deformation mechanisms and bending moment have been investigated. For simple shear, the effects of texture on the relative activity of deformation mechanisms, shear stress and texture evolution have been investigated. Also, the effect of twinning on shear stress and texture evolution has been studied. The numerical analyses predicted a more uniform strain distribution during bending and simple shear for rolled texture compared with extruded texture.

  17. Factors affecting the corrosion performance of Elektron WE43 and WE54 magnesium casting alloys

    Energy Technology Data Exchange (ETDEWEB)

    Karimzadeh, H.; Lyon, P.; King, J.F. (Magnesium Elektron Ltd., Manchester (United Kingdom))

    1998-01-01

    Magnesium sand casting alloys, Elektron WE43 and WE54, are available to users who require excellent mechanical properties and high corrosion resistance combined with light weight. The corrosion behaviour of these alloys depends upon several factors. Whilst Elektron WE43 and WE54 will achieve corrosion rates similar to aluminium based alloys, processing factors can influence the corrosion resistance of the finished part. Molten metal handling prior to casting plays a major role in the level of insoluble zirconium and iron containing zirconium particles. These particles/clusters can have a significant effect upon the corrosion performance of the alloy. The effect of metal handling on the level of the aforementioned particles has been investigated. Heavy metal impurities such as Fe, Ni, Cu, Zn and Ag may be introduced during foundry operations. Critical levels of these elements, both singly and in combination, have been studied. Similarly, the benefits of corrosion resistance achieved in 'high purity' alloys can be negated by contamination of the surface by galvanically active elements. The effect of such contamination has been investigated and practical methods to minimise it are described. Finally, magnesium components can be affected by galvanic corrosion when assembled in contact with other materials in a corrosive environment. Use of appropriate materials and techniques to minimise potential galvanic corrosion problems is illustrated. (orig.)

  18. Lightweight Heat Pipes Made from Magnesium

    Science.gov (United States)

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

    2010-01-01

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

  19. Spatially heterogeneous dynamics investigated via a time-dependent four-point density correlation function

    DEFF Research Database (Denmark)

    Lacevic, N.; Starr, F. W.; Schrøder, Thomas

    2003-01-01

    Relaxation in supercooled liquids above their glass transition and below the onset temperature of "slow" dynamics involves the correlated motion of neighboring particles. This correlated motion results in the appearance of spatially heterogeneous dynamics or "dynamical heterogeneity." Traditional...... two-point time-dependent density correlation functions, while providing information about the transient "caging" of particles on cooling, are unable to provide sufficiently detailed information about correlated motion and dynamical heterogeneity. Here, we study a four-point, time-dependent density......-q behavior of S4(q,t) provides an estimate of the range of correlated particle motion. We find that xi4(t) has a maximum as a function of time t, and that the value of the maximum of xi4(t) increases steadily from less than one particle diameter to a value exceeding nine particle diameters in the temperature...

  20. Autoradiographic investigation of age-dependent proliferation kinetics in the mucosa of rat small intestine

    International Nuclear Information System (INIS)

    Kranz, D.; Laue, R.; Fuhrmann, I.

    1980-01-01

    Aging of cells depends on mitotic activity which is particularly evident in multicellular organisms. The cell kinetics of the mucosa of the small intestine in a total of 244 Wistar rats aged 6 days, 6 weeks, 6, 12, 23 and 28 months, resp., were studied histoautoradiographically. It could be demonstrated that the regeneration rate of cells per hour in the crypts of the small intestine and the migration velocity of the enterocytes differ in young and old individuals, and that the intermitotic cells have age-dependent properties as well. In addition, it could be proved that intermitotic cells have a non growth fraction, too, which, at an advanced age, decreases only slightly although significantly in terms of statistics. For the easily vulnerable crypt epithelium it is a reserve capacity and ban be included in the proliferating pool if necessary. (author)

  1. An investigation of the open-loop amplification of Reynolds number dependent processes by wave distortion

    Science.gov (United States)

    Purdy, K. R.; Ventrice, M. B.; Fang, J.

    1972-01-01

    Analytical and experimental studies were initiated to determine if the response of a constant temperature hot wire anemometer to acoustic oscillations could serve as an analog to the response of the drop vaporization burning rate process to acoustic oscillations, and, perhaps, also as an analog to any Reynolds number dependent process. The motivation behind this study was a recent analytical study which showed that distorted acoustic oscillations could amplify the open-loop response of vaporization limited combustion. This type of amplification may be the cause of unstable combustion in liquid propellant rocket engines. The analytical results obtained for the constant temperature anemometer are similar in nature to those previously obtained for vaporization limited combustion and indicate that the response is dependent on the amount and type of distortion as well as other factors, such as sound pressure level, Mach number and hot wire temperature. Preliminary results indicate qualitative agreement between theory and experiment.

  2. Investigation of the pH‐dependence of dye‐doped protein–protein interactions

    OpenAIRE

    Nudelman, Roman; Gloukhikh, Ekaterina; Rekun, Antonina; Richter, Shachar

    2016-01-01

    Proteins can dramatically change their conformation under environmental conditions such as temperature and pH. In this context, Glycoprotein's conformational determination is challenging. This is due to the variety of domains which contain rich chemical characters existing within this complex. Here we demonstrate a new, straightforward and efficient technique that uses the pH‐dependent properties of dyes‐doped Pig Gastric Mucin (PGM) for predicting and controlling protein–protein interaction ...

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

    OpenAIRE

    Junji Takaya

    2015-01-01

    Magnesium deficiency during pregnancy as a result of insufficient or low intake of magnesium is common in developing and developed countries. Previous reports have shown that intracellular magnesium of cord blood platelets is lower among small for gestational age (SGA) groups than that of appropriate for gestational age (AGA) groups, suggesting that intrauterine magnesium deficiency may result in SGA. Additionally, the risk of adult-onset diseases such as insulin resistance syndrome is greate...

  4. Magnesium status and the effect of magnesium supplementation in feline hypertrophic cardiomyopathy.

    OpenAIRE

    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 wit...

  5. Crystallization of Esomeprazole Magnesium Water/Butanol Solvate.

    Science.gov (United States)

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

    2016-04-23

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

  6. Corrosion Monitoring of PEO-Pretreated Magnesium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gnedenkov, A. S.; Sinebryukhov, S. L.; Mashtalyar, D. V.; Gnedenkov, S. V.; Sergienko, V. I. [Institute of Chemistry, Vladivostok (Russian Federation)

    2017-06-15

    The MA8 alloy (formula Mg-Mn-Ce) has been shown to have greater corrosion stability than the VMD10 magnesium alloy (formula Mg-Zn-Zr-Y) in chloride-containing solutions by Scanning Vibrating Electrode Technique (SVET) and by optical microscopy, gravimetry, and volumetry. It has been established that the crucial factor for the corrosion activity of these samples is the occurrence of microgalvanic coupling at the sample surface. The peculiarities of the kinetics and mechanism of the corrosion in the local heterogeneous regions of the magnesium alloy surface were investigated by localized electrochemical techniques. The stages of the corrosion process in artificial defects in the coating obtained by plasma electrolytic oxidation (PEO) at the surface of the MA8 magnesium alloy were also studied. The analysis of the experimental data enabled us to determine that the corrosion process in the defect zone develops predominantly at the magnesium/coating interface. Based on the measurements of the corrosion rate of the samples with PEO and composite polymer-containing coatings, the best anticorrosion properties were displayed by the composite polymer-containing coatings.

  7. Investigation of solutions of state-dependent multi-impulsive boundary value problems

    Czech Academy of Sciences Publication Activity Database

    Rontó, András; Rachůnková, I.; Rontó, M.; Rachůnek, L.

    2017-01-01

    Roč. 24, č. 2 (2017), s. 287-312 ISSN 1072-947X R&D Projects: GA ČR(CZ) GA14-06958S Institutional support: RVO:67985840 Keywords : state-dependent multi-impulsive systems * non-linear boundary value problem * parametrization technique Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 0.290, year: 2016 https://www.degruyter.com/view/j/gmj.2017.24.issue-2/gmj-2016-0084/gmj-2016-0084. xml

  8. Investigation of solutions of state-dependent multi-impulsive boundary value problems

    Czech Academy of Sciences Publication Activity Database

    Rontó, András; Rachůnková, I.; Rontó, M.; Rachůnek, L.

    2017-01-01

    Roč. 24, č. 2 (2017), s. 287-312 ISSN 1072-947X R&D Projects: GA ČR(CZ) GA14-06958S Institutional support: RVO:67985840 Keywords : state-dependent multi-impulsive systems * non-linear boundary value problem * parametrization technique Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 0.290, year: 2016 https://www.degruyter.com/view/j/gmj.2017.24.issue-2/gmj-2016-0084/gmj-2016-0084.xml

  9. Synthesis of Nano-Light Magnesium Hydride for Hydrogen Storage ...

    African Journals Online (AJOL)

    Abstract. Nano-light magnesium hydride that has the capability for hydrogen storage was synthesized from treatment of magnesium ribbon with hydrogen peroxide. The optimum time for complete hydrogenation of the magnesium hydride was 5 hours.

  10. The effect of serum magnesium levels and serum endothelin-1 levels on bone mineral density in protein energy malnutrition.

    Science.gov (United States)

    Ozturk, C F; Karakelleoglu, C; Orbak, Z; Yildiz, L

    2012-06-01

    An inadequate and imbalanced intake of protein and energy results in protein-energy malnutrition (PEM). It is known that bone mineral density and serum magnesium levels are low in malnourished children. However, the roles of serum magnesium and endothelin-1 (ET-1) levels in the pathophysiology of bone mineralization are obscure. Thus, the relationships between serum magnesium and ET-1 levels and the changes in bone mineral density were investigated in this study. There was a total of 32 subjects, 25 of them had PEM and seven were controls. While mean serum ET-1 levels of the children with kwashiorkor and marasmus showed no statistically significant difference, mean serum ET-1 levels of both groups were significantly higher than that of the control group. Serum magnesium levels were lower than normal value in 9 (36%) of 25 malnourished children. Malnourished children included in this study were divided into two subgroups according to their serum magnesium levels. While mean serum ET-1 levels in the group with low magnesium levels were significantly higher than that of the group with normal magnesium levels (p malnutrition. Our study suggested that lower magnesium levels and higher ET-1 levels might be important factors in changes of bone mineral density in malnutrition. We recommend that the malnourished patients, especially with hypomagnesaemia, should be treated with magnesium early.

  11. An investigation of the general regularity of size dependence of reaction kinetics of nanoparticles

    International Nuclear Information System (INIS)

    Cui, Zixiang; Duan, Huijuan; Xue, Yongqiang; Li, Ping

    2015-01-01

    In the processes of preparation and application of nanomaterials, the chemical reactions of nanoparticles are often involved, and the size of nanoparticles has dramatic influence on the reaction kinetics. Nevertheless, there are many conflicts on regularities of size dependence of reaction kinetic parameters, and these conflicts have not been explained so far. In this paper, taking the reaction of nano-ZnO (average diameter is from 20.96 to 53.31 nm) with acrylic acid solution as a system, the influence regularities of the particle size on the kinetic parameters were researched. The regularities were consistent with that in most literatures, but inconsistent with that in a few of literatures, the reasons for the conflicts were interpreted. The reasons can be attributed to two factors: one is improper data processing for fewer data points, and the other is the difference between solid particles and porous particles. A general regularity of the size dependence of reaction kinetics for solid particles was obtained. The regularity shows that with the size of nanoparticles decreasing, the rate constant and the reaction order increase, while the apparent activation energy and the pre-exponential factor decrease; and the relationships of the logarithm of rate constant, the logarithm of pre-exponential factor, and the apparent activation energy to the reciprocal of the particle size are linear, respectively

  12. Selectivity coefficients of ion-selective magnesium electrodes used for simultaneous determination of magnesium and calcium ions.

    Science.gov (United States)

    Maj-Zurawska, Magdalena; Lewenstam, Andrzej

    2011-12-15

    Membrane ion-selective magnesium electrodes are commonly used to determine ionized magnesium concentration in blood serum and intracellular fluid by potentiometric clinical analyzers. The selectivity of these electrodes against calcium ion is typically insufficient to avoid calcium interference in blood serum analysis. For this reason the selectivity coefficient for calcium ion has to be studied to make possible any mathematical corrections for calcium ion influence. Existing methods relate to the thermodynamic concept of ISE response which suggest a single constant value of the selectivity coefficient and slope that are stable over the concentration ranges of calcium and magnesium ions in the samples. Unfortunately, this rarely happens, and we rather observe dependences on solution and membrane composition, readout time, matrices (anticoagulant, vial coats) that justify usage of apparent selectivities and slopes. To get the practical insight into the response of magnesium ion-selective electrodes a novel method for estimating the selectivity coefficients and the slope of the electrode characteristics is proposed. This method is an effective starting point for selecting electrodes and designing transient signal software in a potentiometric clinical analyzer. The method allows obtaining the ionized magnesium concentration in blood serum with minimal possible error by addressing the assessed targets, i.e. apparent selectivity and slope. The method is based on computer simulation and on the Nicolsky-Eisenman equation. Usually only a few iterations are needed to obtain stable congruent results. The method presented is particularly useful in conditions where is not possible to obtain calibration curve, which is typical for clinical analyzer where at most three point calibration is performed. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Investigation of the zenith angle dependence of cosmic-ray muons ...

    Indian Academy of Sciences (India)

    Abstract. Angular distribution of cosmic-ray muons at sea level has been investigated using the. Geant4 simulation package. The model used in the simulations was tested by comparing the sim- ulation results with the measurements made using the Berkeley Lab cosmic ray detector. Primary particles' energy and fluxes ...

  14. Investigation of the zenith angle dependence of cosmic-ray muons ...

    Indian Academy of Sciences (India)

    Angular distribution of cosmic-ray muons at sea level has been investigated using the Geant4 simulation package. The model used in the simulations was tested by comparing the simulation results with the measurements made using the Berkeley Lab cosmic ray detector. Primary particles' energy and fluxes were obtained ...

  15. Effect of magnesium supplementation on blood rheology in NOS inhibition-induced hypertension model.

    Science.gov (United States)

    Cengiz, Melike; Ülker, Pinar; Üyüklü, Mehmet; Yaraş, Nazmi; Özen, Nur; Aslan, Mutay; Özyurt, Dilek; Basralı, Filiz

    2016-01-27

    This study investigated the effects of magnesium on blood rheological properties and blood pressure in nitric oxide synthase (NOS) inhibition-induced hypertension model. Hypertension was induced by oral administration of the nonselective NOS inhibitor N-nitro-L-arginine methyl ester (L-NAME, 25 mg/kg/day) for 6 weeks and systolic blood pressure was measured by the tail-cuff method. The groups receiving magnesium supplementation were fed with rat chow containing 0.8% magnesium oxide during the experiment. At the end of experiment, blood samples were obtained from abdominal aorta, using ether anesthesia. Plasma and erythrocyte magnesium levels were determined by the atomic absorption spectrometer. RBC deformability and aggregation were determined by rotational ektacytometry. Plasma fibrinogen concentration was evaluated by ELISA. Whole blood and plasma viscosities were determined by viscometer and intracellular free Ca++ level was measured by using spectroflurometric method. Blood pressure was elevated in hypertensive groups and suppressed by magnesium therapy. Plasma viscosity and RBC aggregation were found to be higher in hypertensive rats than control animals and these parameters significantly decreased in magnesium supplemented hypertensive animals. Other measurements were not different between experimental groups. These results confirm that blood pressure, plasma viscosity and RBC aggregation increased in NOS inhibition-induced hypertension model and oral magnesium supplementation improved these parameters.

  16. Mineral water intake reduces blood pressure among subjects with low urinary magnesium and calcium levels

    Science.gov (United States)

    Rylander, Ragnar; Arnaud, Maurice J

    2004-01-01

    Background Several previous epidemiological studies have shown a relation between drinking water quality and death in cardiovascular disease whereas others have not found such a relationship. An intervention study was undertaken to evaluate the effect of water with added magnesium and natural mineral water on blood pressure. Methods A group of 70 subjects with borderline hypertension was recruited and consumed 1) a water low in minerals, 2) magnesium enriched water or 3) natural mineral water, in a random, double blind fashion during four weeks. Results Among persons with an initial low excretion of magnesium or calcium in the urine, the urinary excretion of magnesium was increased in the groups consuming the two waters containing magnesium after 4 weeks. A significant decrease in blood pressure was found in the group consuming mineral water at 2 and 4 weeks. Conclusion The results suggest that minerals taken in water are significant for the body burden and that an intake of mineral water among persons with a low urinary excretion of magnesium or calcium may decrease the blood pressure. Further studies should investigate the extent of mineral deficiency in different populations and the efficiency of different vehicles for supplying minerals, particularly magnesium and calcium. PMID:15571635

  17. Mineral water intake reduces blood pressure among subjects with low urinary magnesium and calcium levels

    Directory of Open Access Journals (Sweden)

    Arnaud Maurice J

    2004-11-01

    Full Text Available Abstract Background Several previous epidemiological studies have shown a relation between drinking water quality and death in cardiovascular disease whereas others have not found such a relationship. An intervention study was undertaken to evaluate the effect of water with added magnesium and natural mineral water on blood pressure. Methods A group of 70 subjects with borderline hypertension was recruited and consumed 1 a water low in minerals, 2 magnesium enriched water or 3 natural mineral water, in a random, double blind fashion during four weeks. Results Among persons with an initial low excretion of magnesium or calcium in the urine, the urinary excretion of magnesium was increased in the groups consuming the two waters containing magnesium after 4 weeks. A significant decrease in blood pressure was found in the group consuming mineral water at 2 and 4 weeks. Conclusion The results suggest that minerals taken in water are significant for the body burden and that an intake of mineral water among persons with a low urinary excretion of magnesium or calcium may decrease the blood pressure. Further studies should investigate the extent of mineral deficiency in different populations and the efficiency of different vehicles for supplying minerals, particularly magnesium and calcium.

  18. Proton-pump inhibitor use is associated with lower urinary magnesium excretion.

    Science.gov (United States)

    William, Jeffrey H; Nelson, Rachel; Hayman, Najwah; Mukamal, Kenneth J; Danziger, John

    2014-12-01

    Although multiple recent studies have confirmed an association between chronic proton-pump inhibitor (PPI) use and hypomagnesaemia, the physiologic explanation for this association remains uncertain. To address this, we investigated the association of PPI use with urinary magnesium excretion. We measured 24-hour urine magnesium excretion in collections performed for nephrolithiasis evaluation in 278 consecutive ambulatory patients and determined PPI use from contemporaneous medical records. There were 50 (18%) PPI users at the time of urine collection. The mean daily urinary magnesium was 84.6 ± 42.8 mg in PPI users, compared with 101.2 ± 41.1 mg in non-PPI users (P = 0.01). In adjusted analyses, PPI use was associated with 10.54 ± 5.30 mg/day lower daily urinary magnesium excretion (P = 0.05). Diuretic use did not significantly modify the effect of PPI on urinary magnesium. As a control, PPI use was not associated with other urinary indicators of nutritional intake. Our findings suggest that PPI use is associated with lower 24-hour urine magnesium excretion. Whether this reflects decreased intestinal uptake due to PPI exposure, or residual confounding due to decreased magnesium intake, requires further study. © 2014 Asian Pacific Society of Nephrology.

  19. Correcting magnesium deficiencies may prolong life

    Directory of Open Access Journals (Sweden)

    Rowe WJ

    2012-02-01

    Full Text Available William J RoweFormer Assistant Clinical Professor of Medicine, Medical University of Ohio at Toledo, Ohio, USAAbstract: The International Space Station provides an extraordinary facility to study the accelerated aging process in microgravity, which could be triggered by significant reductions in magnesium (Mg ion levels with, in turn, elevations of catecholamines and vicious cycles between the two. With space flight there are significant reductions of serum Mg (P < 0.0001 that have been shown in large studies of astronauts and cosmonauts. The loss of the functional capacity of the cardiovascular system with space flight is over ten times faster than the course of aging on Earth. Mg is an antioxidant and calcium blocker and in space there is oxidative stress, insulin resistance, and inflammatory conditions with evidence in experimental animals of significant endothelial injuries and damage to mitochondria. The aging process is associated with progressive shortening of telomeres, repetitive DNA sequences, and proteins that cap and protect the ends of chromosomes. Telomerase can elongate pre-existing telomeres to maintain length and chromosome stability. Low telomerase triggers increased catecholamines while the sensitivity of telomere synthesis to Mg ions is primarily seen for the longer elongation products. Mg stabilizes DNA and promotes DNA replication and transcription, whereas low Mg might accelerate cellular senescence by reducing DNA stability, protein synthesis, and function of mitochondria. Telomerase, in binding to short DNAs, is Mg dependent. On Earth, in humans, a year might be required to detect changes in telomeres, but in space there is a predictably much shorter duration required for detection, which is therefore more reasonable in time and cost. Before and after a space mission, telomere lengths and telomerase enzyme activity can be determined and compared with age-matched control rats on Earth. The effect of Mg supplementation

  20. MAGNESIUM METABOLISM AND CLINICAL CHARACTERISTICS OF PATIENTS WITH CHRONIC ISCHEMIC HEART DISEASE

    Directory of Open Access Journals (Sweden)

    A. V. Yezhov

    2010-01-01

    Full Text Available Aim. To study relationship of the clinical state and cardiac functional parameters with magnesium metabolism indices in patients with chronic ischemic heart disease (IHD.Material and methods. Patients with stable angina pectoris, II-III class (n=480 were involved into the study. Evaluation of the following items was performed: disease course, anxiodepressive syndrome intensity, exercise tolerance, blood and urine electrolyte profile, systolic and diastolic left ventricle function, endothelium-dependent and endotheliumnondependent vasodilatation, i/v magnesium load test, Holter electrocardiogram monitoring.Results. High prevalence of systemic magnesium deficiency (17.9 and 37.5% according to serum and erythrocyte levels, respectively was found in IHD patients. Severity of magnesium deficiency in IHD patients depended on duration of disease, experience of myocardial infarction, myocardial ischemia seriousness, disorders of endothelium vasodilating function and left ventricle diastolic function, severity of concomitant anxiety. Exercise tests were changed in IHD patients with magnesium deficiency.Conclusion. The study data let to consider that magnesium deficiency involves into the IHD pathogenesis.

  1. Functional Relevance of Different Basal Ganglia Pathways Investigated in a Spiking Model with Reward Dependent Plasticity

    Directory of Open Access Journals (Sweden)

    Pierre Berthet

    2016-07-01

    Full Text Available The brain enables animals to behaviourally adapt in order to survive in a complex and dynamic environment, but how reward-oriented behaviours are achieved and computed by its underlying neural circuitry is an open question. To address this concern, we have developed a spiking model of the basal ganglia (BG that learns to dis-inhibit the action leading to a reward despite ongoing changes in the reward schedule. The architecture of the network features the two pathways commonly described in BG, the direct (denoted D1 and the indirect (denoted D2 pathway, as well as a loop involving striatum and the dopaminergic system. The activity of these dopaminergic neurons conveys the reward prediction error (RPE, which determines the magnitude of synaptic plasticity within the different pathways. All plastic connections implement a versatile four-factor learning rule derived from Bayesian inference that depends upon pre- and postsynaptic activity, receptor type and dopamine level. Synaptic weight updates occur in the D1 or D2 pathways depending on the sign of the RPE, and an efference copy informs upstream nuclei about the action selected. We demonstrate successful performance of the system in a multiple-choice learning task with a transiently changing reward schedule. We simulate lesioning of the various pathways and show that a condition without the D2 pathway fares worse than one without D1. Additionally, we simulate the degeneration observed in Parkinson’s disease (PD by decreasing the number of dopaminergic neurons during learning. The results suggest that the D1 pathway impairment in PD might have been overlooked. Furthermore, an analysis of the alterations in the synaptic weights shows that using the absolute reward value instead of the RPE leads to a larger change in D1.

  2. Investigating the temperature dependence of photomultiplier quantum efficiency when operating in the visible spectrum

    CERN Document Server

    Clawson, Savannah Ellen

    2017-01-01

    The quantum efficiency of a Burle 8850 photomultiplier tube with a potassium-caesium-antimony (bialkali) photocathode was determined by attenuating a 1 mW HeNe laser emitting at 633 nm and measuring the signal frequency when the laser was incident on the photomultiplier. A temperature range of 5 $^{\\circ}$C $-$ 20 $^{\\circ}$C was investigated and it was found that the quantum efficiency decreases with temperature, with the signal frequency decreasing at a faster rate than the dark current frequency. Therefore, it was concluded that it would not be beneficial to cool photomultiplier tubes operating in the visible spectrum for use in collinear laser spectroscopy due to a decreasing signal-to-noise ratio. The signal pulse height distribution was also analysed and found to be independent of temperature within the range investigated.

  3. Magnesium deficiency and increased inflammation: current perspectives.

    Science.gov (United States)

    Nielsen, Forrest H

    2018-01-01

    Animal studies have shown that magnesium deficiency induces an inflammatory response that results in leukocyte and macrophage activation, release of inflammatory cytokines and acute-phase proteins, and excessive production of free radicals. Animal and in vitro studies indicate that the primary mechanism through which magnesium deficiency has this effect is through increasing cellular Ca 2+ , which is the signal that results in the priming of cells to give the inflammatory response. Primary pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin (IL)-1; the messenger cytokine IL-6; cytokine responders E-selectin, intracellular adhesion molecule-1 and vascular cell adhesion molecule-1; and acute-phase reactants C-reactive protein and fibrinogen have been determined to associate magnesium deficiency with chronic low-grade inflammation (inflammatory stress). When magnesium dietary intake, supplementation, and/or serum concentration suggest/s the presence of magnesium deficiency, it often is associated with low-grade inflammation and/or with pathological conditions for which inflammatory stress is considered a risk factor. When magnesium intake, supplementation, and/or serum concentration suggest/s an adequate status, magnesium generally has not been found to significantly affect markers of chronic low-grade inflammation or chronic disease. The consistency of these findings can be modified by other nutritional and metabolic factors that affect inflammatory and oxidative stress. In spite of this, findings to date provide convincing evidence that magnesium deficiency is a significant contributor to chronic low-grade inflammation that is a risk factor for a variety of pathological conditions such as cardiovascular disease, hypertension, and diabetes. Because magnesium deficiency commonly occurs in countries where foods rich in magnesium are not consumed in recommended amounts, magnesium should be considered an element of significant nutritional concern

  4. In situ membrane bending setup for strain-dependent scanning transmission x-ray microscopy investigations.

    Science.gov (United States)

    Finizio, S; Wintz, S; Kirk, E; Raabe, J

    2016-12-01

    We present a setup that allows for the in situ generation of tensile strains by bending x-ray transparent Si 3 N 4 membranes with the application of a pressure difference between the two sides of the membrane, enabling the possibility to employ high resolution space- and time-resolved scanning transmission x-ray microscopy for the investigation of the magneto-elastic coupling.

  5. The Relationship between Childhood Maltreatment and Emotional Dysregulation in Self Mutilation: An Investigation among Substance Dependent Patients.

    Science.gov (United States)

    Karagöz, Başak; Dağ, İhsan

    2015-03-01

    The present study aims to examine the role of emotion dysregulation and childhood maltreatment in self mutilation (SM) of substance dependent patients. Specifically, the present study examined whether emotion dysregulation and its dimensions, and childhood maltreatment and its dimensions were associated with SM. The relationship between emotion dysregulation and childhood maltreatment was also investigated. The sample of study consisted of 55 alcohol dependent and 24 opiate dependent patients (n=79). Substance dependence was diagnosed by means of the Structured Clinical Interview for DSM-IV-TR (SCID-I), Turkish version. Childhood Trauma Questionnaire (CTQ) and Difficulties in Emotion Regulation Scale (DERS) were used. Findings indicated that substance dependents with SM and without SM were differentiated in terms of overall emotion dysregulation. Results also suggest the relevance of three specific dimensions of emotion dysregulation to SM: Difficulties engaging in goal-directed behaviors when experiencing negative emotions, difficulties controlling impulsive behaviors when experiencing negative emotions, and limited access to effective emotion regulation strategies. These dimensions were predicted from childhood emotional maltreatment and neglect. It is also revealed that substance dependents with SM had higher points than those without SM on emotional childhood maltreatment and neglect, physical childhood maltreatment. Results were supported by the literature suggested that self-mutilation functions as a emotional regulation strategy. Findings also suggested that self- mutilation is related to early relationships take place in family environment in which individuals grow up.

  6. Newton method for the optimization of a new constitutive equation for the plastic flow dependent on the strain. Application to magnesium alloys AZ80 and AZ61; El metodo de Newton para la optimizacion de una nueva ecuacion constitutiva para la fluencia plastica dependiente de la deformacion. Aplicacin a las aleaciones de magnesio AZ80 y AZ61

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, V.; Roeorp, R.; Carsi, M.; Ruano, O. A.

    2013-07-01

    A new numerical algorithm has been developed, based on Newton's method, for optimizing the parameters of a new strain dependent constitutive equation, based on the Garofalo equation. The adjustment is direct, with second order algorithms, for an equation derived from that of Garofalo with a nonlinear objective function. This new optimization algorithm has been applied to creep data of two magnesium alloys AZ80 and AZ61, having an unusual plastic behavior. A certain pseudo-stationary exists in the curves studied, in the sense that the usual deformation states are not manifested in an obvious way. The parameters of the new constitutive equation, dependent on strain, have been determined for these alloys. For analyzing the precision of the parameters and the accuracy of modeling of the stress-strain curves, a statistical treatment has been applied which allows assessing the quality of the constitutive equation proposed and the consistency of these parameters. Stress-strain curves have been compared with the modeling results, reaching a good agreement between the experimental data and the resulting modeling. (Author)

  7. Corrosion resistance of titanium ion implanted AZ91 magnesium alloy

    International Nuclear Information System (INIS)

    Liu Chenglong; Xin Yunchang; Tian Xiubo; Zhao, J.; Chu, Paul K.

    2007-01-01

    Degradable metal alloys constitute a new class of materials for load-bearing biomedical implants. Owing to their good mechanical properties and biocompatibility, magnesium alloys are promising in degradable prosthetic implants. The objective of this study is to improve the corrosion behavior of surgical AZ91 magnesium alloy by titanium ion implantation. The surface characteristics of the ion implanted layer in the magnesium alloys are examined. The authors' results disclose that an intermixed layer is produced and the surface oxidized films are mainly composed of titanium oxide with a lesser amount of magnesium oxide. X-ray photoelectron spectroscopy reveals that the oxide has three layers. The outer layer which is 10 nm thick is mainly composed of MgO and TiO 2 with some Mg(OH) 2 . The middle layer that is 50 nm thick comprises predominantly TiO 2 and MgO with minor contributions from MgAl 2 O 4 and TiO. The third layer from the surface is rich in metallic Mg, Ti, Al, and Ti 3 Al. The effects of Ti ion implantation on the corrosion resistance and electrochemical behavior of the magnesium alloys are investigated in simulated body fluids at 37±1 deg. C using electrochemical impedance spectroscopy and open circuit potential techniques. Compared to the unimplanted AZ91 alloy, titanium ion implantation significantly shifts the open circuit potential (OCP) to a more positive potential and improves the corrosion resistance at OCP. This phenomenon can be ascribed to the more compact surface oxide film, enhanced reoxidation on the implanted surface, as well as the increased β-Mg 12 Al 17 phase

  8. An investigation of the photon energy dependence of the EPR alanine dosimetry system

    International Nuclear Information System (INIS)

    Bergstrand, Eva Stabell; Shortt, Ken R; Ross, Carl K; Hole, Eli Olaug

    2003-01-01

    The electron paramagnetic resonance (EPR) alanine dosimetry system is based on EPR measurements of radicals formed in alanine by ionizing radiation. The system has been studied to determine its energy dependence for photons in the 10-30 MV region relative to those of 60 Co and to find out if the system would be suitable for dosimetry comparisons. The irradiations were carried out at the National Research Council, Ottawa, Canada and the doses ranged from 8 to 54 Gy. The EPR measurements were performed at the University of Oslo, Norway. The ratio of the slope of the alanine reading versus dose-to-water curve for a certain linac photon beam quality and the corresponding slope for a reference 60 Co γ-radiation gives an experimental measure of the relative dose-to-water response of the EPR alanine dosimetry system. For calculating the linear regression coefficients of these alanine reading versus dose curves, the method of weighted least squares was used. This method is assumed to produce more accurate regression coefficients when applied to EPR dosimetry than the common method of standard least squares. The overall uncertainty on the ratio of slopes was between 0.5 and 0.6% for all three linac energies. The relative response for all the linac beams compared to cobalt was less than unity: by about 0.5% for the 20 and 30 MV points but by more than 1% for the 10 MV point. The given standard uncertainties negate concluding that there is any significant internal variation in the measured response as a function of beam quality between the three linac energies. Thus, we calculated the average dose response for all three energies and found that the alanine response is 0.8% (±0.5%) lower for high energy x-rays than for 60 Co γ-rays. This result indicates a small energy dependence in the alanine response for the high-energy photons relative to 60 Co which may be significant. This result is specific to our dosimetry system (alanine with 20% polyethylene binder pressed into a

  9. Magnesium growth in magnesium deuteride thin films during deuterium desorption

    Energy Technology Data Exchange (ETDEWEB)

    Checchetto, R., E-mail: riccardo.checchetto@unitn.it [Dipartimento di Fisica and CNISM, Università di Trento, Via Sommarive 14, I-38123 Trento (Italy); Miotello, A. [Dipartimento di Fisica and CNISM, Università di Trento, Via Sommarive 14, I-38123 Trento (Italy); Mengucci, P.; Barucca, G. [Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Università Politecnica delle Marche, I-60131 Ancona (Italy)

    2013-12-15

    Highlights: ► Highly oriented Pd-capped magnesium deuteride thin films. ► The MgD{sub 2} dissociation was studied at temperatures not exceeding 100 °C. ► The structure of the film samples was analyzed by XRD and TEM. ► The transformation is controlled by the re-growth velocity of the Mg layers. ► The transformation is thermally activated, activation energy value of 1.3 ± 0.1 eV. -- Abstract: Pd- capped nanocrystalline magnesium thin films having columnar structure were deposited on Si substrate by e-gun deposition and submitted to thermal annealing in D{sub 2} atmosphere to promote the metal to deuteride phase transformation. The kinetics of the reverse deuteride to metal transformation was studied by Thermal Desorption Spectroscopy (TDS) while the structure of the as deposited and transformed samples was analyzed by X-rays diffraction and Transmission Electron Microscopy (TEM). In Pd- capped MgD{sub 2} thin films the deuteride to metal transformation begins at the interface between un-reacted Mg and transformed MgD{sub 2} layers. The D{sub 2} desorption kinetics is controlled by MgD{sub 2}/Mg interface effects, specifically the re-growth velocity of the Mg layers. The Mg re-growth has thermally activated character and shows an activation energy value of 1.3 ± 0.1 eV.

  10. Dosimetric investigation depending on tumor location in patient breast in partial breast irradiation

    International Nuclear Information System (INIS)

    Kim, Min Joo; Park, So Hyun; Jung, Joo Young; Woong, Cho; Suh, Tae Suk

    2012-01-01

    The Partial Breast Irradiation (PBI) technique, which involves radiation beam delivery techniques that use a limited range of treatment volumes, has been a challenging approach that is worthy of consideration compared to whole-breast radiation therapy (WBRT). Because of a small target volumes used in the PBI technique, the radiation dose can be safely delivered to the targeted tissue without the unwanted delivery of radiation to normal breast tissues and organ at risk (OAR), such as contralateral breast, lung and heart.Through PBI technique, better cosmetic outcomes and minimizing damages to OARs could be expected and also the daily dose can be increased with smaller number of fractionation in radiation therapy. The purpose of this study was to evaluate the dosimetric effects according to tumor locations in patient's breast for Partial Breast Irradiation (PBI) technique using three Dimensional Conformal Radiation Therapy (3DCRT), Electron Beam Radiation therapy (EBRT) and Helical-tomotherapy (H-TOMO). Dosimetric comparisons of PBI technique for 3DCRT, EBRT, and H-TOMO depending on the classified tumor locations were performed. H-TOMO delivered the low dose to lager volume to surrounding normal tissue, such as the heart and lungs compared to 3DCRT and EBRT although it had the same degree of target coverage as the other methods (3DCRT, EBRT). EBRT had a curative effect for early-stage breast cancers located in the lower and inner sections (LIQ-S, LIQ-D)

  11. Improving Corrosion Resistance and Biocompatibility of Magnesium Alloy by Sodium Hydroxide and Hydrofluoric Acid Treatments

    Directory of Open Access Journals (Sweden)

    Chang-Jiang Pan

    2016-12-01

    Full Text Available Owing to excellent mechanical property and biodegradation, magnesium-based alloys have been widely investigated for temporary implants such as cardiovascular stent and bone graft; however, the fast biodegradation in physiological environment and the limited surface biocompatibility hinder their clinical applications. In the present study, magnesium alloy was treated by sodium hydroxide (NaOH and hydrogen fluoride (HF solutions, respectively, to produce the chemical conversion layers with the aim of improving the corrosion resistance and biocompatibility. The results of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR and X-ray photoelectron spectroscopy (XPS indicated that the chemical conversion layers of magnesium hydroxide or magnesium fluoride were obtained successfully. Sodium hydroxide treatment can significantly enhance the surface hydrophilicity while hydrogen fluoride treatment improved the surface hydrophobicity. Both the chemical conversion layers can obviously improve the corrosion resistance of the pristine magnesium alloy. Due to the hydrophobicity of magnesium fluoride, HF-treated magnesium alloy showed the relative better corrosion resistance than that of NaOH-treated substrate. According to the results of hemolysis assay and platelet adhesion, the chemical surface modified samples exhibited improved blood compatibility as compared to the pristine magnesium alloy. Furthermore, the chemical surface modified samples improved cytocompatibility to endothelial cells, the cells had better cell adhesion and proliferative profiles on the modified surfaces. Due to the excellent hydrophilicity, the NaOH-treated substrate displayed better blood compatibility and cytocompatibility to endothelial cells than that of HF-treated sample. It was considered that the method of the present study can be used for the surface modification of the magnesium alloy to enhance the corrosion resistance and biocompatibility.

  12. The Investigation of Magnesium Perchlorate/Iron Phase-mineral Mixtures as a Possible Source of Oxygen and Chlorine Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars

    Science.gov (United States)

    Sutter, B.; Heil, E.; Archer, P. D.; Ming, D. W.; Eigenbrode, J. L.; Franz, H. B.; Glavin, D. P.; McAdam, A. C.; Mahaffy, P. R.; Niles, P. B.; hide

    2014-01-01

    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover detect-ed O2 and HCl gas releases from the Rocknest (RN) eolian bedform and the John Klein (JK) and Cumber-land (CB) drill hole materials in Gale Crater (Fig. 1) [1,2]. Chlorinated hydrocarbons have also been detect-ed by the SAM quadrupole mass spectrometer (QMS) and gas chromatography/mass spectrometer (GCMS) [1,2,3,4]. These detections along with the detection of perchlorate (ClO4(-)) by the Mars Phoenix Lander's Wet Chemistry Laboratory (WCL) [5] suggesting perchlo-rate is a possible candidate for evolved O2 and chlorine species. Laboratory thermal analysis of individual per-chlorates has yet to provide an unequivocal tempera-ture match to the SAM O2 and HCl release data [1,2]. Catalytic reactions of Fe phases in the Gale Crater ma-terial with perchlorates can potentially reduce the de-composition temperatures of these otherwise pure per-chlorate/chlorate phases [e.g., 6,7]. Iron mineralogy found in the Rocknest materials when mixed with Ca-perchlorate was found to cause O2 release temperatures to be closer match to the SAM O2 release data and enhance HCl gas releases. Exact matches to the SAM data has unfortnunately not been achieved with Ca-perchlorate-Fe-phase mixtures [8]. The effects of Fe-phases on magnesium perchlorate thermal decomposi-tion release of O2 and HCl have not been evaluated and may provide improved matches to the SAM O2 and HCl release data. This work will evaluate the thermal decomposition of magnesium perchlorate mixed with fayalite/magnetite phase and a Mauna Kea palagonite (HWMK 919). The objectives are to 1) summarize O2 and HCl releases from the Gale Crater materials, and 2) evaluate the O2 and HCl releases from the Mg-perchlorate + Fe phase mixtures to determine if Mg-perchlorate mixed with Fe-phases can explain the Gale Crater O2 and HCl releases.

  13. Magnesium stannide as a high-capacity anode for magnesium-ion batteries

    Science.gov (United States)

    Nguyen, Dan-Thien; Song, Seung-Wan

    2017-11-01

    Driven by the limited global resources of lithium, magnesium metal batteries are considered as potential energy storage systems. The battery chemistry of magnesium metal anode, however, limits the selection of electrolytes, cathode materials and working temperature, making the realization of magnesium metal batteries complicated. Herein, we report the development of a new magnesium-insertion anode, magnesium stannide (Mg2Sn), and demonstrate reversible electrochemical Mg2+-extraction and insertion of Mg2Sn anode at 0.2 V versus Mg, delivering discharge capacity of 270 mAhg-1 in a half-cell with the electrolyte of PhMgCl/THF and enabling of room temperature magnesium-ion batteries with Mg2Sn anode combined with Mg-free oxide cathode and conventional-type electrolyte of Mg(TFSI)2/diglyme. The combination of Mg2Sn anode with various cathodes and electrolytes holds great promise for enabling room temperature magnesium-ion batteries.

  14. Investigating physical field effects on the size-dependent dynamic behavior of inhomogeneous nanoscale plates

    Science.gov (United States)

    Ebrahimi, Farzad; Reza Barati, Mohammad

    2017-02-01

    This article investigates the thermo-mechanical vibration frequencies of magneto-electro-thermo-elastic functionally graded (METE-FG) nanoplates in the framework of refined four-unknown shear deformation plate theory. The present nanoplate is subjected to various kinds of thermal loads with uniform, linear and nonlinear distributions. The nonlinear distribution is considered as heat conduction and sinusoidal temperature rise. The present refined theory captures the influences of shear deformations without the need for shear correction factors. Thermo-magneto-electro-elastic coefficients of the FG nanoplate vary gradually along the thickness according to the power-law form. The scale coefficient is taken into consideration implementing the nonlocal elasticity of Eringen. The governing equations are derived through Hamilton's principle and are solved analytically. The frequency response is compared with those of previously published data. The obtained results are presented for the thermo-mechanical vibrations of the FG nanobeams to investigate the effects of material graduation, nonlocal parameter, mode number, slenderness ratio and thermal loading in detail. The present study is associated to aerospace, mechanical and nuclear engineering structures which are under thermal loads.

  15. Fluid Bed Dehydration of Magnesium Chloride

    Science.gov (United States)

    Adham, K.; Lee, C.; O'Keefe, K.

    Molten salt electrolysis of MgCl2 is commonly used for the production of magnesium metal. However, the electrolysis feed must be completely dry with minimum oxygen content. Therefore, complete dehydration of the MgCl2 brine or the hydrated prill is a required process, which is very challenging because of the ease of thermal degradation due to hydrolysis of magnesium chloride.

  16. Magnesium - distribution and basic metabolism | Olhaberry | South ...

    African Journals Online (AJOL)

    Magnesium is extensively distributed in soil, water and plants. It is essential for ehzymatic reactions requiring adenosine triphosphate, and the recommended dietary allowance in man is 5 - 10 mg/kg/d. About 50% of magnesium in man is stored in bone, where it is regulated by parathyroid hormone'and 1,25(OH)2-D3.

  17. A Shortened versus Standard Matched Postpartum Magnesium ...

    African Journals Online (AJOL)

    Magnesium sulphate is currently the most ideal drug for the treatment of eclampsia but its use in Nigeria is still limited due its cost and clinicians inexperience with the drug. The purpose of this study was to determine whether a shortened postpartum course of magnesium sulphate is as effective as the standard Pritchard ...

  18. Magnesium removal in the electrolytic zinc industry

    NARCIS (Netherlands)

    Booster, J.L.

    2003-01-01

    Electrolytic zinc plants need to take measures to control the magnesium content in their process liquors, because the natural magnesium bleed does not balance the input from concentrates. Presently used methods are environmentally unfriendly (due to the production of large amounts of waste gypsum)

  19. Comparison of Serum Calcium and Magnesium Between ...

    African Journals Online (AJOL)

    Background: Evidence suggests the involvement of calcium and magnesium metabolism in the pathophysiology of preeclampsia. However, findings from studies are heterogenous and inconsistent. Aim: The study aimed to compare the total serum calcium and magnesium levels in preeclamptic women with that of ...

  20. Hydrogen in magnesium palladium thin layer structures

    NARCIS (Netherlands)

    Kruijtzer, G.L.

    2008-01-01

    In this thesis, the study of hydrogen storage, absorption and desorption in magnesium layers is described. The magnesium layers have a thickness of 50-500 nm and are covered by a palladium layer which acts as a hydrogen dissociation/association catalyst. The study was preformed under ultra high

  1. Magnesium supplementation in children with attention deficit ...

    African Journals Online (AJOL)

    Background: Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder with associated mineral deficiency. Aim: To assess magnesium level in ADHD children and compare it to the normal levels in children. Then, to detect the effect of magnesium supplementation as an add on therapy, ...

  2. Magnesium diffusion in several aluminum alloys

    Science.gov (United States)

    Holub, K. J.; Matienzo, L. J.

    Various surface quality defects or stains are sometimes observed on rolled aluminum. Two such defects, "white lacy" stain and "dirty" metal, appear to be caused by the formation of locally thicker films of hydrated aluminum and magnesium oxides, respectively. This paper examines the formation of these oxides, particularly MgO, on three aluminum alloys with varying bulk magnesium concentrations, namely 5052, 3004 and 3003, containing 2.64, 0.96 and 0.03% magnesium, respectively. Samples were prepared and heat treated in flowing air as a function of temperature and time. The surfaces were examined by Auger electron spectroscopy to determine the relative ratio of the magnesium and aluminum present on the oxide surfaces. Auger depth profiling was used to characterize the composition of the oxides. Surface morphologies, as observed by ultra-high resolution scanning electron microscopy, also were compared. Alloys containing higher bulk magnesium contents, i.e., 5052 and 3004, showed more magnesium diffusion and magnesium oxide formation on the sample surface. At high temperatures, the surface of 5052 tends to be almost totally MgO. Only limited magnesium diffusion and MgO formation was observed on the 3003 alloy.

  3. An investigation of nutrient-dependent mRNA translation in Drosophila larvae

    Directory of Open Access Journals (Sweden)

    Sabarish Nagarajan

    2014-10-01

    Full Text Available The larval period of the Drosophila life cycle is characterized by immense growth. In nutrient rich conditions, larvae increase in mass approximately two hundred-fold in five days. However, upon nutrient deprivation, growth is arrested. The prevailing view is that dietary amino acids drive this larval growth by activating the conserved insulin/PI3 kinase and Target of rapamycin (TOR pathways and promoting anabolic metabolism. One key anabolic process is protein synthesis. However, few studies have attempted to measure mRNA translation during larval development or examine the signaling requirements for nutrient-dependent regulation. Our work addresses this issue. Using polysome analyses, we observed that starvation rapidly (within thirty minutes decreased larval mRNA translation, with a maximal decrease at 6–18 hours. By analyzing individual genes, we observed that nutrient-deprivation led to a general reduction in mRNA translation, regardless of any starvation-mediated changes (increase or decrease in total transcript levels. Although sugars and amino acids are key regulators of translation in animal cells and are the major macronutrients in the larval diet, we found that they alone were not sufficient to maintain mRNA translation in larvae. The insulin/PI3 kinase and TOR pathways are widely proposed as the main link between nutrients and mRNA translation in animal cells. However, we found that genetic activation of PI3K and TOR signaling, or regulation of two effectors – 4EBP and S6K – could not prevent the starvation-mediated translation inhibition. Similarly, we showed that the nutrient stress-activated eIF2α kinases, GCN2 and PERK, were not required for starvation-induced inhibition of translation in larvae. These findings indicate that nutrient control of mRNA translation in larvae is more complex than simply amino acid activation of insulin and TOR signaling.

  4. Method of frequency dependent correlations: investigating the variability of total solar irradiance

    Science.gov (United States)

    Pelt, J.; Käpylä, M. J.; Olspert, N.

    2017-04-01

    Context. This paper contributes to the field of modeling and hindcasting of the total solar irradiance (TSI) based on different proxy data that extend further back in time than the TSI that is measured from satellites. Aims: We introduce a simple method to analyze persistent frequency-dependent correlations (FDCs) between the time series and use these correlations to hindcast missing historical TSI values. We try to avoid arbitrary choices of the free parameters of the model by computing them using an optimization procedure. The method can be regarded as a general tool for pairs of data sets, where correlating and anticorrelating components can be separated into non-overlapping regions in frequency domain. Methods: Our method is based on low-pass and band-pass filtering with a Gaussian transfer function combined with de-trending and computation of envelope curves. Results: We find a major controversy between the historical proxies and satellite-measured targets: a large variance is detected between the low-frequency parts of targets, while the low-frequency proxy behavior of different measurement series is consistent with high precision. We also show that even though the rotational signal is not strongly manifested in the targets and proxies, it becomes clearly visible in FDC spectrum. A significant part of the variability can be explained by a very simple model consisting of two components: the original proxy describing blanketing by sunspots, and the low-pass-filtered curve describing the overall activity level. The models with the full library of the different building blocks can be applied to hindcasting with a high level of confidence, Rc ≈ 0.90. The usefulness of these models is limited by the major target controversy. Conclusions: The application of the new method to solar data allows us to obtain important insights into the different TSI modeling procedures and their capabilities for hindcasting based on the directly observed time intervals.

  5. Investigation into the Dependence of Noise Generated By Standing Cars on the Engine Power

    Directory of Open Access Journals (Sweden)

    Julius Gineika

    2012-12-01

    Full Text Available Ambient noise harms a number of citizens in Europe. The major sources of environmental noise are that generated by cars in streets, parking lots, railway lines and airports as well as noise from local sources (fans, transformers. According to the methodology for noise measurement, engine testing has been carried out. The conducted analysis has been focused on engine capacity and the distance between vehicles and equipment. Equivalent, maximum and minimum sound levels at different frequencies have been measured accepting that errors may range up to 2 %. Maximum sound level has been reached using the engine of 2000 cm3 petrol capacity. At a half-meter distance, the equivalent sound level reaches 89 dB(A, whereas the noise level decreases moving away from the car. The obtained results of tested cars disclose that according to engine capacity, the majority of the investigated cars are technically faulty and therefore significantly exceed noise levels.Article in Lithuanian

  6. Finite element investigation of temperature dependence of elastic properties of carbon nanotube reinforced polypropylene

    Science.gov (United States)

    Ahmadi, Masoud; Ansari, Reza; Rouhi, Saeed

    2017-11-01

    This paper aims to investigate the elastic modulus of the polypropylene matrix reinforced by carbon nanotubes at different temperatures. To this end, the finite element approach is employed. The nanotubes with different volume fractions and aspect ratios (the ratio of length to diameter) are embedded in the polymer matrix. Besides, random and regular algorithms are utilized to disperse carbon nanotubes in the matrix. It is seen that as the pure polypropylene, the elastic modulus of carbon nanotube reinforced polypropylene decreases by increasing the temperature. It is also observed that when the carbon nanotubes are dispersed parallelly and the load is applied along the nanotube directions, the largest improvement in the elastic modulus of the nanotube/polypropylene nanocomposites is obtained.

  7. Irradiation effects in magnesium and aluminium alloys

    International Nuclear Information System (INIS)

    Sturcken, E.F.

    1979-01-01

    Effects of neutron irradiation on microstructure, mechanical properties and swelling of several magnesium and aluminium alloys were studied. The neutron fluences of 2-3 X 10 22 n/cm 2 , >0.2 MeV produced displacement doses of 20 to 45 displacements per atom (dpa). Ductility of the magnesium alloys was severely reduced by irradiation induced recrystallization and precipitation of various forms. Precipitation of transmuted silicon occurred in the aluminium alloys. However, the effect on ductility was much less than for the magnesium alloys. The magnesium and aluminium alloys had excellent resistance to swelling: The best magnesium alloy was Mg/3.0 wt% Al/0.19 wt% Ca; its density decreased by only 0.13%. The best aluminium alloy was 6063, with a density decrease of 0.22%. (Auth.)

  8. On the ionization of interstellar magnesium

    International Nuclear Information System (INIS)

    Gurzadyan, G.A.

    1977-01-01

    It has been shown that two concentric ionization zones of interstellar magnesium must exist around each star: internal, with a radius coinciding with that of the zone of hydrogen ionization Ssub(H); and external, with a radius greater than Ssub(H), by one order. Unlike interstellar hydrogen, interstellar magnesium is ionized throughout the Galaxy. It also transpires that the ionizing radiation of ordinary hot stars cannot provide for the observed high degree of ionization of interstellar magnesium. The discrepance can be eliminated by assuming the existence of circumstellar clouds or additional ionization sources of interstellar magnesium (X-ray background radiation, high-energy particles, etc.). Stars of the B5 and BO class play the main role in the formation of ionization zones of interstellar magnesium; the contribution of O class stars is negligible (<1%). (Auth.)

  9. Recrystallization of magnesium deformed at low temperatures

    International Nuclear Information System (INIS)

    Fromageau, R.; Pastol, J.L.; Revel, G.

    1978-01-01

    The recrystallization of magnesium was studied after rolling at temperatures ranging between 248 and 373 K. For zone refined magnesium the annealing behaviour as observed by electrical resistivity measurements showed two stages at about 250 K and 400 K due respectively to recrystallization and grain growth. The activation energy associated with the recrystallization stage was 0.75 +- 0.01 eV. In less pure magnesium, with nominal purity 99.99 and 99.9%, the recrystallization stage was decomposed into two substages. Activation energies were determined in relation with deformation temperature and purity. The magnesium of intermediate purity (99.99%) behaved similarly to the lowest purity metal when it was deformed at high temperature and to the purest magnesium when the deformation was made at low temperature. This behaviour was discussed in connection with the theories of Luecke and Cahn. (Auth.)

  10. Improved cytotoxicity testing of magnesium materials

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Janine, E-mail: janine.fischer@hzg.de [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Department for Structural Research on Macromolecules, Max-Planck Str. 1, D - 21502 Geesthacht (Germany); Proefrock, Daniel [Helmholtz-Zentrum Geesthacht, Institute for Coastal Research, Department for Marine Bioanalytical Chemistry, Max-Planck Str. 1, D - 21502 Geesthacht (Germany); Hort, Norbert [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Department for Magnesium Processing, Max-Planck Str. 1, D - 21502 Geesthacht (Germany); Willumeit, Regine; Feyerabend, Frank [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Department for Structural Research on Macromolecules, Max-Planck Str. 1, D - 21502 Geesthacht (Germany)

    2011-06-25

    Metallic magnesium (Mg) and its alloys are highly suitable for medical applications as biocompatible and biodegradable implant materials. Magnesium has mechanical properties similar to bone, stimulates bone regeneration, is an essential non-toxic element for the human body and degrades completely within the body environment. In consequence, magnesium is a promising candidate as implant material for orthopaedic applications. Protocols using the guideline of current ISO standards should be carefully evaluated when applying them for the characterization of the cytotoxic potential of degradable magnesium materials. For as-cast material we recommend using 10 times more extraction medium than recommended by the ISO standards to obtain reasonable results for reliable cytotoxicity rankings of degradable materials in vitro. In addition primary isolated human osteoblasts or mesenchymal stem cells should be used to test magnesium materials.

  11. The magnesium chelation step in chlorophyll biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, J.

    1990-11-01

    In photosynthetic organisms, the biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins, and various 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 (Proto). Insertion of iron leads to the formation of hemes, while insertion of magnesium is the first step unique to chlorophyll formation. This project is directed toward identifying the enzyme(s) responsible for magnesium chelation and elucidating the mechanism which regulates the flux of precursors through the branch point enzymes in isolated chloroplasts. Using intact chloroplasts from greening cucumber cotyledons, we have confirmed the ATP requirement for Mg-Proto formation. Use of non-hydrolyzable ATP analogs, uncouplers and ionophores has led to the conclusions that ATP hydrolysis is necessary, but that this hydrolysis is not linked to the requirement for membrane intactness by transmembrane ion gradients or electrical potentials. The enzyme(s) are flexible with respect to the porphyrin substrate specificity, accepting porphyrins with -vinyl, -ethyl, or -H substituents at the 2 and 4 positions. The activity increases approximately four-fold during greening. Possible physiological feedback inhibitors such as heme, protochlorophyllide, and chlorophyllide had no specific effect on the activity. The activity has now been assayed in barely, corn and peas, with the system from peas almost ten-fold more active than the cucumber system. Work is continuing in pea chloroplasts with the development of a continuous assay and investigation of the feasibility of characterizing an active, organelle-free preparation. 6 figs.

  12. Influence of temperature on fracture mechanisms of magnesium composites

    Energy Technology Data Exchange (ETDEWEB)

    Gaertnerova, V.; Jaeger, A.; Trojanova, Z. [Dept. of Metal Physics, Charles Univ., Praha (Czech Republic); Chalupova, M. [Dept. of Materials Engineering, Univ. of Zilina, Zilina (Slovakia)

    2005-07-01

    Magnesium alloy AZ91 (9% Al, 1% Zn, 0.2% Mn in wt.%) with different reinforcements has been used to study fracture mechanisms and crack development. SiC particles and/or Saffil fibres were used as the reinforcement. Fracture surfaces of specimens prepared by impact tests in the temperature range from room temperature to 300 C were investigated by scanning electron microscope (SEM). Possible mechanisms of fracture are discussed in the relation to the test temperature. (orig.)

  13. Bioavailability of magnesium from different pharmaceutical formulations.

    Science.gov (United States)

    Siener, Roswitha; Jahnen, Andrea; Hesse, Albrecht

    2011-04-01

    Magnesium is suggested to reduce intestinal oxalate absorption and to act as an inhibitor of calcium oxalate crystallization in the urine. However, previous studies have shown only minimal increase in urinary magnesium excretion following oral magnesium supplementation, possibly due to its low bioavailability. This study was performed to examine the bioavailability of magnesium from two different pharmaceutical formulations of magnesium oxide (MgO). Thirteen healthy male volunteers (22-31 years) were recruited from university students and staff, and all completed the study. During the baseline phase, subjects collected two 24-h urines while on their usual diet. Throughout the control and test phases, the subjects consumed a standardized diet calculated according to the recommendations. During the test phases, subjects received two magnesium preparations in a cross-over procedure. With each preparation, MgO-capsules and MgO-effervescent tablets, 450 mg magnesium was supplemented. On the control day and the two test days, fractional urine collection was performed and six corresponding blood samples were taken. In the follow-up phase, subjects continued to take the respective preparation while on their usual diet and collected 24-h urines weekly. With standardized conditions, urinary magnesium excretion increased by 40% after ingestion of the effervescent tablets, and by only 20% after intake of the capsules. The results indicate better bioavailability of magnesium from the effervescent tablets than from the capsules. This may be attributed to the fact that the tablets have to be dissolved in water before ingestion so that magnesium becomes ionized, which is an important precondition for absorption.

  14. Magnesium sulfate therapy in preeclampsia and eclampsia.

    Science.gov (United States)

    Witlin, A G; Sibai, B M

    1998-11-01

    To review the available evidence regarding efficacy, benefits, and risks of magnesium sulfate seizure prophylaxis in women with preeclampsia or eclampsia. The English-language literature in MEDLINE was searched from 1966 through February 1998 using the terms "magnesium sulfate," "seizure," "preeclampsia," "eclampsia," and "hypertension in pregnancy." Reviews of bibliographies of retrieved articles and consultation with experts in the field provided additional references. All relevant English-language clinical research articles retrieved were reviewed. Randomized controlled trials, retrospective reviews, and observational studies specifically addressing efficacy, benefits, or side effects of magnesium sulfate therapy in preeclampsia or eclampsia were chosen. Nineteen randomized controlled trials, five retrospective studies, and eight observational reports were reviewed. The criteria used for inclusion were as follows: randomized controlled trials evaluating use of magnesium sulfate in eclampsia, preeclampsia, and hypertensive disorders of pregnancy; nonrandomized studies of historical interest; "classic" observational studies; and recent retrospective studies evaluating efficacy of magnesium sulfate therapy, using relative risk and 95% confidence intervals where applicable. Magnesium sulfate therapy has been associated with increased length of labor, increased cesarean delivery rate, increased postpartum bleeding, increased respiratory depression, decreased neuromuscular transmission, and maternal death from overdose. A summary of randomized, controlled trials in women with eclampsia reveals recurrent seizures in 216 (23.1%) of 935 women treated with phenytoin or diazepam, compared with recurrent seizures in only 88 (9.4%) of 932 magnesium-treated women. Randomized controlled trials in women with severe preeclampsia collectively revealed seizures in 22 (2.8%) of 793 women treated with antihypertensive agents, compared with seizures in only seven of 815 (0

  15. Investigation of point and extended defects in electron irradiated silicon—Dependence on the particle energy

    Energy Technology Data Exchange (ETDEWEB)

    Radu, R.; Pintilie, I.; Nistor, L. C. [National Institute of Materials Physics, Atomistilor 105 bis, Magurele 077125 (Romania); Fretwurst, E.; Lindstroem, G. [Institute for Experimental Physics, University of Hamburg, D-22761 Hamburg (Germany); Makarenko, L. F. [Belarusian State University, Independence Ave. 4, 220030 Minsk (Belarus)

    2015-04-28

    This work is focusing on generation, time evolution, and impact on the electrical performance of silicon diodes impaired by radiation induced active defects. n-type silicon diodes had been irradiated with electrons ranging from 1.5 MeV to 27 MeV. It is shown that the formation of small clusters starts already after irradiation with high fluence of 1.5 MeV electrons. An increase of the introduction rates of both point defects and small clusters with increasing energy is seen, showing saturation for electron energies above ∼15 MeV. The changes in the leakage current at low irradiation fluence-values proved to be determined by the change in the configuration of the tri-vacancy (V{sub 3}). Similar to V{sub 3}, other cluster related defects are showing bistability indicating that they might be associated with larger vacancy clusters. The change of the space charge density with irradiation and with annealing time after irradiation is fully described by accounting for the radiation induced trapping centers. High resolution electron microscopy investigations correlated with the annealing experiments revealed changes in the spatial structure of the defects. Furthermore, it is shown that while the generation of point defects is well described by the classical Non Ionizing Energy Loss (NIEL), the formation of small defect clusters is better described by the “effective NIEL” using results from molecular dynamics simulations.

  16. Temperature dependent mechanical property of PZT film: an investigation by nanoindentation.

    Directory of Open Access Journals (Sweden)

    Yingwei Li

    Full Text Available Load-depth curves of an unpoled Lead Zirconate Titanate (PZT film composite as a function of temperature were measured by nanoindentation technique. Its reduce modulus and hardness were calculated by the typical Oliver-Pharr method. Then the true modulus and hardness of the PZT film were assessed by decoupling the influence of substrate using methods proposed by Zhou et al. and Korsunsky et al., respectively. Results show that the indentation depth and modulus increase, but the hardness decreases at elevated temperature. The increasing of indentation depth and the decreasing of hardness are thought to be caused by the decreasing of the critical stress needed to excite dislocation initiation at high temperature. The increasing of true modulus is attributed to the reducing of recoverable indentation depth induced by back-switched domains. The influence of residual stress on the indentation behavior of PZT film composite was also investigated by measuring its load-depth curves with pre-load strains.

  17. Systematic investigation of a family of gradient-dependent functionals for solids

    Science.gov (United States)

    Haas, Philipp; Tran, Fabien; Blaha, Peter; Pedroza, Luana S.; da Silva, Antonio J. R.; Odashima, Mariana M.; Capelle, Klaus

    2010-03-01

    Eleven density functionals are compared with regard to their performance for the lattice constants of solids. We consider standard functionals, such as the local-density approximation and the Perdew-Burke-Ernzerhof (PBE) generalized-gradient approximation (GGA), as well as variations of PBE GGA, such as PBEsol and similar functionals, PBE-type functionals employing a tighter Lieb-Oxford bound, and combinations thereof. On a test set of 60 solids, we perform a system-by-system analysis for selected functionals and a full statistical analysis for all of them. The impact of restoring the gradient expansion and of tightening the Lieb-Oxford bound is discussed, and confronted with previous results obtained from other codes, functionals or test sets. No functional is uniformly good for all investigated systems, but surprisingly, and pleasingly, the simplest possible modifications to PBE turn out to have the most beneficial effect on its performance. The atomization energy of molecules was also considered and on a testing set of six molecules, we found that the PBE functional is clearly the best, the others leading to strong overbinding.

  18. Theoretical and Experimental Investigations of Polyelectrolyte Adsorption Dependence on Molecular Weight.

    Science.gov (United States)

    Xie, Fei; Lu, Hongduo; Nylander, Tommy; Wågberg, Lars; Forsman, Jan

    2016-06-14

    This work focuses on adsorption of polyions onto oppositely charged surfaces and on responses to the addition of a simple monovalent salt as well as to the polyion length (degree of polymerization). We also discuss possible mechanisms underlying observed differences, of the adsorbed amount on silica surfaces at high pH, between seemingly similar polyions. This involves theoretical modeling, utilizing classical polymer density functional theory (DFT). We furthermore investigate how long- and short-chain versions of the polymer adsorb onto carboxymethylated cellulose, carrying a high negative charge. Interestingly enough, comparing results obtained for the two different surfaces, we observe an opposite qualitative response for the molecular weight. The large polymer adsorbs more strongly at a silica surface, but for cellulose at low salt levels, there are indications that the trend is opposite. Another difference is the very slow adsorption process observed for cellulose, particularly with short polymers; in fact, with short polymers, we were sometimes unable to establish any adsorption plateau at all. We speculate that the slow dynamics is due to a gradual diffusion of short polymers into the cellulose matrix. This phenomenon could also explain why short-chain polymers seem to adsorb more strongly than long-chain ones, at low salt concentrations, provided that the latter then are too large to enter the cellulose pores. Cellulose swelling at high salt concentrations might diminish these differences, leading to more similar adsorbed amounts or even a lower adsorption for short chains.

  19. A microstructural investigation of the depth-dependent response of cartilage during stress relaxation

    Science.gov (United States)

    Zhang, Geran; Thambyah, Ashvin; Broom, Neil

    2009-08-01

    The poro-visco-hyperelastic nature of articular cartilage has been studied extensively, yet little has been done to correlate its unique mechanical properties with its microstructural response to load. Making such a correlation would help determine how the microstructure of cartilage, with its zonally-differentiated fibrillar microarchitecture and water-content, influences the overall macro-level mechanical response. A total of eight cartilage-on-bone samples were subjected to stress relaxation tests, conducted via stepwise indentation, and using a 2mm diameter cylindrical indenter. Each step indentation consisted of a 10% compressive strain, up to 80%. At each strain increment the specimen was allowed to fully relax to an equilibrium stress before compressing it further. From the stress relaxation curve at each strain level, peak and equilibrium stresses were recorded. For the microstructural investigation, specimens stress-equilibrated at 20%, 40%, 60% and 80% strain, were chemically fixed to capture the deformed state and then cryo-sectioned and imaged using differential interference contrast (DIC) microscopy. It was found that stress relaxation, i.e. the time from peak stress to equilibrium, occurred at a slower rate at the larger levels of compressive strain. Peak stresses increased exponentially with increasing levels of strain. The equilibrium stress relationship with compressive strain level was largely linear but between 60% and 80% strain, the change in equilibrium stress increased dramatically. The microstructural data showed how at lower strain levels, much of the load was distributed laterally within the upper zones of the cartilage matrix. At higher strain levels (>60%) the deep zone fibrillar alignment was sheared and this may explain the abrupt rise in equilibrium stress levels. Finally, the increase in peak stress at higher strain-levels is likely due to a decreased interstitial fluid permeability associated with an increasingly consolidated matrix.

  20. Corrosion Behavior of Simulated HLW Glass in the Presence of Magnesium Ion

    Directory of Open Access Journals (Sweden)

    Toshikatsu Maeda

    2011-01-01

    Full Text Available Static leach tests were conducted for simulated HLW glass in MgCl2 solution for up to 92 days to investigate the dissolution mechanism of HLW glass under coastal repository condition. Under the condition that magnesium ion exists in leachate, the dissolution rate of the glass did not decrease with time during leaching, while the rate decreased when the magnesium ion depleted in the leachate. In addition, altered layer including magnesium and silica was observed at the surface of the glass after the leach tests. The present results imply that dissolution of the glass is accompanied with formation of magnesium silicate consuming silica, a glass network former. As a consequence, the glass dissolved with an initial high dissolution rate.

  1. Stress Corrosion Cracking of ZEK100 Magnesium Alloy for Automotive Applications

    Science.gov (United States)

    Pang, Xin; Shi, Chao; Zavadil, Renata

    ZEK100 magnesium alloy has attracted considerable interest for automotive body structure applications in light-weight vehicles due to its excellent formability at room temperature. However, the intrinsic tendency of magnesium alloys to corrode under wet conditions has been a concern. Reports on the corrosion resistance and, in particular, the stress corrosion cracking (SCC) susceptibility of ZEK100 under automotive service conditions have been scarce. In this work, the SCC of ZEK100 magnesium alloy was characterized by slow strain rate testing method. The effects of microstructure and corrosion environment on the SCC resistance of the alloy have been investigated. The results represent outcomes from a US-Canada-China collaborative research and development project — Magnesium Front End Research and Development (MFERD) currently underway.

  2. Effect of bicarbonate on biodegradation behaviour of pure magnesium in a simulated body fluid

    International Nuclear Information System (INIS)

    Li, Zaichun; Song, Guang-Ling; Song, Shizhe

    2014-01-01

    The effect of bicarbonate on biodegradation of pure magnesium in a simulated body fluid is investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, polarization curve and electrochemical impedance spectroscopy. The results show that magnesium biodegrades rapidly and non-uniformly during 27 h of immersion in four simulated body fluid solutions containing different concentrations of bicarbonate. The biodegradation rate first decreases and then increases with time. A small amount of bicarbonate in simulated body fluid has an inhibition effect on the Mg dissolution, while an overdose of bicarbonate addition activates the magnesium surface in the simulated body fluid. The interesting phenomena can be interpreted by a surface film model involving precipitation of calcium carbonate and further ionization of bicarbonate in the simulated body fluids, incorporation of calcium, carbonate and phosphate compounds in the surface film, and development of chloride-induced pitting corrosion damage on the magnesium with time

  3. Magnesium deficiency and increased inflammation: current perspectives

    Directory of Open Access Journals (Sweden)

    Nielsen FH

    2018-01-01

    Full Text Available Forrest H Nielsen Research Nutritionist Consultant, Grand Forks, ND, USA Abstract: Animal studies have shown that magnesium deficiency induces an inflammatory response that results in leukocyte and macrophage activation, release of inflammatory cytokines and acute-phase proteins, and excessive production of free radicals. Animal and in vitro studies indicate that the primary mechanism through which magnesium deficiency has this effect is through increasing cellular Ca2+, which is the signal that results in the priming of cells to give the inflammatory response. Primary pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin (IL-1; the messenger cytokine IL-6; cytokine responders E-selectin, intracellular adhesion molecule-1 and vascular cell adhesion molecule-1; and acute-phase reactants C-reactive protein and fibrinogen have been determined to associate magnesium deficiency with chronic low-grade inflammation (inflammatory stress. When magnesium dietary intake, supplementation, and/or serum concentration suggest/s the presence of magnesium deficiency, it often is associated with low-grade inflammation and/or with pathological conditions for which inflammatory stress is considered a risk factor. When magnesium intake, supplementation, and/or serum concentration suggest/s an adequate status, magnesium generally has not been found to significantly affect markers of chronic low-grade inflammation or chronic disease. The consistency of these findings can be modified by other nutritional and metabolic factors that affect inflammatory and oxidative stress. In spite of this, findings to date provide convincing evidence that magnesium deficiency is a significant contributor to chronic low-grade inflammation that is a risk factor for a variety of pathological conditions such as cardiovascular disease, hypertension, and diabetes. Because magnesium deficiency commonly occurs in countries where foods rich in magnesium are not consumed in

  4. Changes in growth and magnesium concentration of wheat and coffee plants grown under various magnesium and water stress treatments

    OpenAIRE

    Ceylan, Yasemin

    2015-01-01

    Magnesium (Mg) deficiency has become a widespread problem in acidic and sandy agricultural soils, and it is often associated with marginal soil conditions such as drought stress. Impairment in growth and development of sink organs is a common consequence of Mg deficiency. However, mode of action of these impairments is not well understood. This study was conducted to investigate the changes in growth and Mg concentrations of wheat (Triticum aestivum cv. Adana99) and coffee (Coffea arabica cv....

  5. Magnesium supplement in pregnancy-induced hypertension: effects on maternal and neonatal magnesium and calcium homeostasis

    DEFF Research Database (Denmark)

    Rudnicki, M; Frølich, A; Fischer-Rasmussen, W

    1991-01-01

    The objective of this study was to evaluate the effect of low dose magnesium supplement upon maternal and fetal serum levels of mineral status in pregnancies complicated with hypertension (PIH). Twenty-five patients with PIH agreed to participate and were randomly allocated, in a double-blind man......The objective of this study was to evaluate the effect of low dose magnesium supplement upon maternal and fetal serum levels of mineral status in pregnancies complicated with hypertension (PIH). Twenty-five patients with PIH agreed to participate and were randomly allocated, in a double......-blind manner, either to intravenous magnesium for 2 days followed by oral magnesium (n = 12) until delivery or placebo (n = 13). In women supplemented with magnesium the level of magnesium increased from 0.74 to 1.02 mmol/l during the first 24 h of inclusion and simultaneously we observed an increased urinary...... loss of magnesium. Serum level and the urinary excretion of magnesium returned to pretreatment level at delivery. Maternal magnesium supplement increased the concentrations of magnesium in umbilical cord and neonatal blood 1 day after delivery. Serum ionized calcium did not change during the study...

  6. Initial deposition mechanism of electroless nickel plating on AZ91D magnesium alloys

    International Nuclear Information System (INIS)

    Song, Y.; Shan, D.; Han, E.

    2006-01-01

    The pretreatment processes and initial deposition mechanism of electroless nickel plating on AZ91D magnesium alloy were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The results showed that alkaline cleaning could remove the greases and oils from the substrate surface. Acid etching could wipe off the metal chippings and oxides. The hydrofluoric acid activating process which could improve the adhesion of coating to substrate played a key role in the subsequent process of electroless nickel plating. The nickel coating was deposited preferentially on the primary α phase and then spread to the eutectic α phase and β phase. The nickel initially nucleated on the primary α phase by a replacement reaction, then grew depending on the autocatalysis function of nickel. The coating on the β phase displayed better adhesion than that on the α phase due to the nails fixing effect. (author)

  7. Magnesium Sulfate in Acute Stroke: A Randomized Double-Blind Clinical Trial

    Directory of Open Access Journals (Sweden)

    S A Mousavi

    2004-08-01

    Full Text Available Background: Administration of magnesium sulfate has neuroprotective effects and reduces infarct volume in animal models of stroke. Previous small clinical trials have reported beneficial effect of magnesium on the outcome in patients with stroke. This study was a randomized, placebo-controlled, double-blind study , investigated the benefit of magnesium sulfate the administration given intravenously as a neuroprotective. Methods: Patients who had cortical infarction in the middle cerebral artery territory (superior or inferior division with moderate neurologic deficits (Orgogozo scale score greater than 30 and less than 70 and onset less than 24 hours were included. The patients were treated with magnesium sulfate (4gr stat and 1gr/hr or placebo for 4 days and examined by a blind investigator. NIH Stroke Scale was obtained on admission and fifth day after stroke. Results: Eighteen patients were given treatment and nineteen patients were given placebo who demonstrated significant beneficial effects on the difference between NIH Stroke Scales on the day of admission and day 5 (3.16 ± 0.98 vs. 1.84 ± 1.06; p = 0.000 respectively. Conclusion: Intravenous magnesium sulfate had significant beneficial effect on acute phase of stroke patients and, as a result, may reduce duration of admission. Keywords: Stroke, Magnesium sulfate, Neuroprotective.

  8. Magnesium substituted hydroxyapatite formation on (Ti,Mg)N coatings produced by cathodic arc PVD technique.

    Science.gov (United States)

    Onder, Sakip; Kok, Fatma Nese; Kazmanli, Kursat; Urgen, Mustafa

    2013-10-01

    In this study, formation of magnesium substituted hydroxyapatite (Ca10-xMgx(PO4)6(OH)2) on (Ti,Mg)N and TiN coating surfaces were investigated. The (Ti1-x,Mgx)N (x=0.064) coatings were deposited on titanium substrates by using cathodic arc physical vapor deposition technique. TiN coated grade 2 titanium substrates were used as reference to understand the role of magnesium on hydroxyapatite (HA) formation. The HA formation experiments was carried out in simulated body fluids (SBF) with three different concentrations (1X SBF, 5X SBF and 5X SBF without magnesium ions) at 37 °C. The coatings and hydroxyapatite films formed were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and FTIR Spectroscopy techniques. The energy dispersive X-ray spectroscopy (EDS) analyses and XRD investigations of the coatings indicated that magnesium was incorporated in the TiN structure rather than forming a separate phase. The comparison between the TiN and (Ti, Mg)N coatings showed that the presence of magnesium in TiN structure facilitated magnesium substituted HA formation on the surface. The (Ti,Mg)N coatings can potentially be used to accelerate the HA formation in vivo conditions without any prior hydroxyapatite coating procedure. © 2013.

  9. Positron Annihilation Spectroscopic Investigation on the Origin of Temperature-Dependent Electrical Response in Methylammonium Lead Iodide Perovskite.

    Science.gov (United States)

    Dhar, Joydeep; Sil, Sayantan; Dey, Arka; Ray, Partha Pratim; Sanyal, Dirtha

    2017-04-20

    Organic-inorganic hybrid perovskite has appeared as one of the leading materials for realizing solution-based high-performing optoelectronic devices. The charge transport properties in this class of material are quite intriguing and still need to be carefully investigated. The temperature-dependent electrical property of methylammonium lead iodide (CH 3 NH 3 PbI 3 ) has been investigated by employing positron annihilation spectroscopy (PAS), which unambiguously reveals the gradual formation of open volume defects with the enhancement in temperature. The high-temperature ionic conductivity is due to the generation of both cationic (CH 3 NH 3 + ) and anionic (I - ) vacancies, possibly because of the elimination of methylammonium iodide (CH 3 NH 3 I) as identified from the coincidence Doppler broadening (CDB) of the positron annihilation spectroscopy. Further, the evolution of temperature-dependent defect density and corresponding electrical responses has been correlated with the structural phase transitions of CH 3 NH 3 PbI 3 . This is the first ever report of temperature-dependent PAS measurement on hybrid lead halide perovskites to understand the nature and the origin of its electrical characteristics arising due to the variation in temperature.

  10. Corrosion of Magnesium in Multimaterial System

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Vineet V.; Agnew, Sean

    2017-08-16

    The TMS Magnesium Committee has been actively involved in presenting cutting-edge research and development and the latest trends related to magnesium and its alloys to industry and academia. Topics including magnesium alloy development, applications, mechanism of deformation and corrosion, thermomechanical processing, modelling, etc. have been captured year after year through the Magnesium Technology symposium and conference proceedings at TMS and through special topics in JOM. Every year, based on the unanimous endorsement from the industry and academia, a topic is selected to address the latest developments within this subject in JOM. In continuation with last year’s coverage of Advances and Achievements in In-Situ Analysis of Corrosions and Structure–Property Relationship in Mg Alloys,[1] this year’s topic focuses on the Corrosion of Magnesium in Multimaterial Systems. Magnesium, the lightest of all the structural materials, has garnered much interest in the transportation, electronics packaging, defense equipments and industries alike and are more commonly being incorporated in multimaterial design concepts.[2-4] However, the application of the same is limited due to its highly corrosive nature, and understanding and mitigating the corrosion of magnesium has been a major research challenge.

  11. Urinary and plasma magnesium and risk of ischemic heart disease

    NARCIS (Netherlands)

    Joosten, Michel M.; Gansevoort, Ron T.; Mukamal, Kenneth J.; van der Harst, Pim; Geleijnse, Johanna M.; Feskens, Edith J. M.; Navis, Gerjan; Bakker, Stephan J. L.

    Background: Previous studies on dietary magnesium and risk of ischemic heart disease (IHD) have yielded inconsistent results, in part because of a lack of direct measures of actual magnesium uptake. Urinary excretion of magnesium, an indicator of dietary magnesium uptake, might provide more

  12. Urinary and plasma magnesium and risk of ischemic heart disease

    NARCIS (Netherlands)

    Joosten, M.M.; Gansevoort, R.T.; Mukamal, K.J.; Harst, van der P.; Geleijnse, J.M.; Feskens, E.J.M.; Navis, G.; Bakker, S.J.L.

    2013-01-01

    BACKGROUND: Previous studies on dietary magnesium and risk of ischemic heart disease (IHD) have yielded inconsistent results, in part because of a lack of direct measures of actual magnesium uptake. Urinary excretion of magnesium, an indicator of dietary magnesium uptake, might provide more

  13. Magnesium bicarbonate as an in situ uranium lixiviant

    International Nuclear Information System (INIS)

    Sibert, J.W.

    1984-01-01

    In the subsurface solution mining of mineral values, especially uranium, in situ, magnesium bicarbonate leaching solution is used instead of sodium, potassium and ammonium carbonate and bicarbonates. The magnesium bicarbonate solution is formed by combining carbon dioxide with magnesium oxide and water. The magnesium bicarbonate lixivant has four major advantages over prior art sodium, potassium and ammonium bicarbonates

  14. Study of magnesium chloride hexahydrate as heat storage material

    Energy Technology Data Exchange (ETDEWEB)

    Pilar, Radim, E-mail: radim.pilar@student.upce.cz [Department of Inorganic Technology, Faculty of Chemical Technology, University of Pardubice, Doubravice 41, 532 10 Pardubice (Czech Republic); Svoboda, Ladislav; Honcova, Pavla; Oravova, Lucie [Department of Inorganic Technology, Faculty of Chemical Technology, University of Pardubice, Doubravice 41, 532 10 Pardubice (Czech Republic)

    2012-10-20

    Highlights: Black-Right-Pointing-Pointer We measured heat capacity of magnesium chloride hexahydrate. Black-Right-Pointing-Pointer Thermal stability of magnesium chloride hexahydrate was tested using DSC. Black-Right-Pointing-Pointer Some nucleating agents were applied to suppress supercooling in magnesium chloride hexahydrate. - Abstract: Heat capacity of MgCl{sub 2}{center_dot}6H{sub 2}O was determined in temperature range from 298.15 to 401.15 K. Polynomial function was used to fit temperature dependence of heat capacity up to 371.15 K and corresponding thermodynamic functions (H{sub T} - H{sub 298.15}, S{sub T} - S{sub 298.15}, G{sub T} - G{sub 298.15}) were calculated. Thermal stability test (50 heating/cooling cycles) of pure MgCl{sub 2}{center_dot}6H{sub 2}O shows supercooling about 37 K, thus some nucleating agents were tested. Addition of SrCO{sub 3} (1 wt%) and Sr(OH){sub 2} (0.5 wt%) almost fully suppresses the supercooling while addition of Mg(OH){sub 2} decreases supercooling by 19 K.

  15. Emerging Applications Using Magnesium Alloy Powders: A Feasibility Study

    Science.gov (United States)

    Tandon, Rajiv; Madan, Deepak

    The use of powder metallurgy offers a potential processing route based on tailored compositions and unique microstructures to achieve high performance in magnesium alloys. This paper highlights recent advances in the production, qualification, and characterization of gas atomized AZ91E, WE43 and Elektron21 alloy powders. Transmission electron microscopy (TEM) was used to understand the bulk and surface structure of the atomized powder. The potential for using these magnesium alloy powders for emerging applications involves establishing compatibility with viable consolidation processes such as cold spray, laser assisted deposition, forging and extrusion. This study summarizes the preliminary results for various ongoing investigations using WE43 powder as an example. Results show that powder metallurgy processed WE43 results in comparable properties to those obtained from cast and wrought and offers potential for improvement.

  16. Treatment of coking wastewater by using manganese and magnesium ores.

    Science.gov (United States)

    Chen, Tianhu; Huang, Xiaoming; Pan, Min; Jin, Song; Peng, Suchuan; Fallgren, Paul H

    2009-09-15

    This study investigated a wastewater treatment technique based on natural minerals. A two-step process using manganese (Mn) and magnesium (Mg) containing ores were tested to remove typical contaminants from coking wastewater. Under acidic conditions, a reactor packed with Mn ore demonstrated strong oxidizing capability and destroyed volatile phenols, chemical oxygen demand (COD)(,) and sulfide from the coking wastewater. The effluent was further treated by using Mg ore to remove ammonium-nitrogen and phosphate in the form of magnesium ammonium phosphate (struvite) precipitates. When pH of the wastewater was adjusted to 1.2, the removal efficiencies for COD, volatile phenol and sulfide reached 70%, 99% and 100%, respectively. During the second step of precipitation, up to 94% of ammonium was removed from the aqueous phase, and precipitated in the form of struvite with phosphorus. The struvite crystals showed a needle-like structure. X-ray diffraction and transmission electron microscopy were used to characterize the crystallized products.

  17. High speed cutting of AZ31 magnesium alloy

    Directory of Open Access Journals (Sweden)

    Liwei Lu

    2016-06-01

    Full Text Available Using LBR-370 numerical control lathe, high speed cutting was applied to AZ31 magnesium alloy. The influence of cutting parameters on microstructure, surface roughness and machining hardening were investigated by using the methods of single factor and orthogonal experiment. The results show that the cutting parameters have an important effect on microstructure, surface roughness and machine hardening. The depth of stress layer, roughness and hardening present a declining tendency with the increase of the cutting speed and also increase with the augment of the cutting depth and feed rate. Moreover, we established a prediction model of the roughness, which has an important guidance on actual machining process of magnesium alloy.

  18. Magnesium supplement in pregnancy-induced hypertension. A clinicopathological study

    DEFF Research Database (Denmark)

    Rudnicki, M; Junge, Jette; Frølich, A

    1990-01-01

    as a double-blind randomized controlled study in which 11 women were allocated to magnesium and 7 to placebo treatment. The treatment comprised a 48-hour intravenous magnesium/placebo infusion followed by daily oral magnesium/placebo intake until one day after delivery. Magnesium supplement increased birth....... There was no significant difference when the magnesium group, the placebo group and the control group were compared separately. The present study suggests that magnesium supplement has a beneficial effect on fetal growth in pregnancy-induced hypertension. With regard to the light and electron microscopic changes we were...... unable to demonstrate any significant difference between the magnesium, placebo and control groups....

  19. Microstructure analysis of magnesium alloy melted by laser irradiation

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  20. Magnesium in North America: A Changing Landscape

    Science.gov (United States)

    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.

  1. Magnesium doping of boron nitride nanotubes

    Science.gov (United States)

    Legg, Robert; Jordan, Kevin

    2015-06-16

    A method to fabricate boron nitride nanotubes incorporating magnesium diboride in their structure. In a first embodiment, magnesium wire is introduced into a reaction feed bundle during a BNNT fabrication process. In a second embodiment, magnesium in powder form is mixed into a nitrogen gas flow during the BNNT fabrication process. MgB.sub.2 yarn may be used for superconducting applications and, in that capacity, has considerably less susceptibility to stress and has considerably better thermal conductivity than these conventional materials when compared to both conventional low and high temperature superconducting materials.

  2. On the hydrogenation mechanism in magnesium I

    DEFF Research Database (Denmark)

    Pedersen, A.S.; Kjøller, John; Larsen, Bent

    1985-01-01

    The first time hydriding of spherical magnesium particles covered by a thin oxide layer and sieve-fractionated into narrow size distributions within the range 40–90 μm was followed by microgravimetry. The size distributions of the fractions were determined by semiautomatic image analysis. The hyd......The first time hydriding of spherical magnesium particles covered by a thin oxide layer and sieve-fractionated into narrow size distributions within the range 40–90 μm was followed by microgravimetry. The size distributions of the fractions were determined by semiautomatic image analysis...... generalizing results from the hydriding of magnesium powders....

  3. A multidisciplinary study on magnesium

    Directory of Open Access Journals (Sweden)

    Radić-Perić Jelena

    2012-01-01

    Full Text Available During plasma electrolytic oxidation of a magnesium alloy (96% Mg, 3% Al, 1% Zn we obtained a luminescence spectrum in the wave number range between 19 950 and 20 400 cm-1. The broad peak with clearly pronounced structure was assigned to the v’-v” = 0 sequence of the B 1Σ+ → X 1Σ+ electronic transition of MgO. Quantum-mechanical perturbative approach was applied to extract the form of the potential energy curves for the electronic states involved in the observed spectrum, from the positions of spectral bands. These potential curves, combined with the results of quantum-chemical calculations of the electric transition moment, were employed in subsequent variational calculations to obtain the Franck-Condon factors and transition moments for the vibrational transitions observed. Comparing the results of these calculations with the measured intensity distribution within the spectrum we derived relative population of the upper electronic state vibration levels. This enabled us to estimate the plasma temperature. Additionally, the temperature was determined by analysis of the recorded A 2Σ+ (v’ = 0 - X 2П (v” = 0 emission spectrum of OH. The composition of plasma containing magnesium, oxygen, and hydrogen under assumption of local thermal equilibrium was calculated in the temperature range up to 12 000 K and for pressures of 105, 106, 107, and 108 Pa, in order to explain the appearance of the observed spectral features and to contribute to elucidation of processes taking place during the electrolytic oxidation of Mg. [Projekat Ministarstva nauke Republike Srbije, br. 172040

  4. MexiB 6 AS A RESULT OF FORTIFICATION OF ETHYLMETHYLHYDROXYPYRIDINE SUCCINATE WITH MAGNESIUM AND PYRIDOXINE: PROTEOME EFFECTS

    Directory of Open Access Journals (Sweden)

    O. A. Gromova

    2016-01-01

    Full Text Available The efficacy of ethylmethylhydroxypyridine succinate (EMHPS  depends on the concentration and activity of proteomic proteins. To provide the body with magnesium and pyridoxine is an important condition for the efficacy of EMHPS because these micronutrients are essential for maintaining neuronal function.Objective: to analyze the biological effects of pyridoxineand magnesium-dependent proteins providing the molecular mechanisms of multi-targeted action of EMHPS,  pyridoxine, and magnesium.Material and methods. Proteins that interact with both pyridoxine and magnesium were found in the genomic and proteomic databases. A list of 78 vitamin B6-dependent proteins, which is based on the available human genome records in NCBIPROTEIN, EMBL,  UNIPROT,  and HumanProteomeMap databases, was analyzed using a functional binding assay. The same assay was also applied to analyze a list 720 magnesium-dependent proteins.Results. The analysis has shown that 78 pyridoxine-dependent proteomic proteins are necessary for: 1 the synthesis and processing of amino acids; 2 cell energy metabolism (ATP synthesis, and 3 the synthesis of neurotransmitters and neuronal membranes. MexiB 6 has numerous synergistic interactions between the molecules of EMHPS,  pyridoxine, and magnesium. The combination of the components of EMHPS,  pyridoxine and magnesium in MexiB 6 (triple synergism allows prediction that the drug has more pronounced clinical effects than the molecules of EMHPS,  which emerges in its antihypoxic and antioxidant activities, the improvement of synaptic transmission of a signal, the neutralization of homocysteine, and the regulation of lipid and carbohydrate metabolism (restoration of cell sensitivity to insulin and carbohydrates in patients with atherosclerosis and in those at risk for diabetes mellitus or obesity. Pyridoxineand magnesium-induced potentiation of the effects of EMHPS may enhance its activity.

  5. Genetic Contribution to Alcohol Dependence: Investigation of a Heterogeneous German Sample of Individuals with Alcohol Dependence, Chronic Alcoholic Pancreatitis, and Alcohol-Related Cirrhosis

    Directory of Open Access Journals (Sweden)

    Jens Treutlein

    2017-07-01

    Full Text Available The present study investigated the genetic contribution to alcohol dependence (AD using genome-wide association data from three German samples. These comprised patients with: (i AD; (ii chronic alcoholic pancreatitis (ACP; and (iii alcohol-related liver cirrhosis (ALC. Single marker, gene-based, and pathway analyses were conducted. A significant association was detected for the ADH1B locus in a gene-based approach (puncorrected = 1.2 × 10−6; pcorrected = 0.020. This was driven by the AD subsample. No association with ADH1B was found in the combined ACP + ALC sample. On first inspection, this seems surprising, since ADH1B is a robustly replicated risk gene for AD and may therefore be expected to be associated also with subgroups of AD patients. The negative finding in the ACP + ALC sample, however, may reflect genetic stratification as well as random fluctuation of allele frequencies in the cases and controls, demonstrating the importance of large samples in which the phenotype is well assessed.

  6. The reference range of serum, plasma and erythrocyte magnesium

    Directory of Open Access Journals (Sweden)

    Suzanna Immanuel

    2006-12-01

    Full Text Available The interest in the clinical importance of serum magnesium level has just recently begun with the analysis and findings of abnormal magnesium level in cardiovascular, metabolic and neuromuscular disorder. Although the serum level does not reflect the body magnesium level, but currently, only serum magnesium determination is widely used. Erythrocyte magnesium is considered more sensitive than serum magnesium as it reflects intracellular magnesium status. According to NCCLS (National Committee for Clinical Laboratory Standards every laboratory is recommended to have its own reference range for the tests it performs, including magnesium determination. The reference range obtained is appropriate for the population and affected by the method and technique. This study aimed to find the reference range of serum and plasma magnesium and also intracellular magnesium i.e. erythrocyte magnesium by direct method, and compare the results of serum and plasma magnesium. Blood was taken from 114-blood donor from Unit Transfusi Darah Daerah (UTDD Budhyarto Palang Merah Indonesia (PMI DKI Jakarta, consisted of 57 male and 57 female, aged 17 – 65 years, clinically healthy according to PMI donor criteria. Blood was taken from blood set, collected into 4 ml vacuum tube without anticoagulant for serum magnesium determination and 3 ml vacuum tube with lithium heparin for determination of erythrocyte and plasma magnesium Determination of magnesium level was performed with clinical chemistry auto analyzer Hitachi 912 by Xylidil Blue method colorimetrically. This study showed no significant difference between serum and heparinized plasma extra cellular magnesium. The reference range for serum or plasma magnesium was 1.30 – 2.00 mEq/L and for erythrocyte magnesium was 4.46 - 7.10 mEq/L. (Med J Indones 2006; 15:229-35Keywords: Reference range, extracellular magnesium, intracellular magnesium

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

    Science.gov (United States)

    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.

  8. Effects of silicon on mechanical properties of AM60 magnesium alloy

    Directory of Open Access Journals (Sweden)

    Hu Yong

    2012-08-01

    Full Text Available Silicon was added to improve the tensile, wear and creep behaviors of AM60 magnesium alloy in this study. The investigation has been undertaken by means of universal testing machine, HBE-3000A Brinell hardness tester, M-2000 friction-wear machine, DMA-Q800 creep machine, optical microscopy (OM and scanning electron microscopy (SEM. The results indicate that the Chinese script type Mg2Si particles are formed by adding Si into the AM60 magnesium alloy. The ultimate tensile strength and hardness of the AM60 magnesium alloy increases with the Si addition, and the ultimate tensile strength and hardness of the AM60+1.0wt.%Si alloy are increased by 12% and 19.8%, respectively in comparison with that of the AM60 magnesium alloy. The wear property and the high temperature creep property of the AM60 magnesium alloy are also improved with Si addition. The wear mechanisms of the AM60 and AM60+1.0wt.%Si alloys are adhesive wear and abrasion wear, respectively. While, the elongation of the AM60 magnesium alloy decreases with the addition of Si. The optimum Si addition content is 1.0wt.%.

  9. Degradation and antibacterial properties of magnesium alloys in artificial urine for potential resorbable ureteral stent applications.

    Science.gov (United States)

    Lock, Jaclyn Y; Wyatt, Eric; Upadhyayula, Srigokul; Whall, Andrew; Nuñez, Vicente; Vullev, Valentine I; Liu, Huinan

    2014-03-01

    This article presents an investigation on the effectiveness of magnesium and its alloys as a novel class of antibacterial and biodegradable materials for ureteral stent applications. Magnesium is a lightweight and biodegradable metallic material with beneficial properties for use in medical devices. Ureteral stent is one such example of a medical device that is widely used to treat ureteral canal blockages clinically. The bacterial colony formation coupled with the encrustation on the stent surface from extended use often leads to clinical complications and contributes to the failure of indwelling medical devices. We demonstrated that magnesium alloys decreased Escherichia coli viability and reduced the colony forming units over a 3-day incubation period in an artificial urine (AU) solution when compared with currently used commercial polyurethane stent. Moreover, the magnesium degradation resulted in alkaline pH and increased magnesium ion concentration in the AU solution. The antibacterial and degradation properties support the potential use of magnesium-based materials for next-generation ureteral stents. Further studies are needed for clinical translation of biodegradable metallic ureteral stents. Copyright © 2013 Society of Plastics Engineers.

  10. In vitro corrosion and biocompatibility study of phytic acid modified WE43 magnesium alloy

    Science.gov (United States)

    Ye, C. H.; Zheng, Y. F.; Wang, S. Q.; Xi, T. F.; Li, Y. D.

    2012-02-01

    Phytic acid (PA) conversion coating on WE43 magnesium alloy was prepared by the method of immersion. The influences of phytic acid solution with different pH on the microstructure, properties of the conversion coating and the corrosion resistance were investigated by SEM, FTIR and potentiodynamic polarization method. Furthermore, the biocompatibility of different pH phytic acid solution modified WE43 magnesium alloys was evaluated by MTT and hemolysis test. The results show that PA can enhance the corrosion resistance of WE43 magnesium especially when the pH value of modified solution is 5 and the cytotoxicity of the PA coated WE43 magnesium alloy is much better than that of the bare WE43 magnesium alloy. Moreover, all the hemolysis rates of the PA coated WE43 Mg alloy were lower than 5%, indicating that the modified Mg alloy met the hemolysis standard of biomaterials. Therefore, PA coating is a good candidate to improve the biocompatibility of WE43 magnesium alloy.

  11. Kinetics of the development of a nonchromate conversion coating for magnesium alloys and magnesium-based metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Nunez, M.A.; Skeldon, P.; Thompson, G.E.; Karimzadeh, H.

    1999-12-01

    Kinetics of the development of a conversion coating from a stannate bath on commercial purity magnesium (Mg{sup comm}), magnesium-based alloys ZC71 and WE43, and a metal matrix composite (MMC), comprising a ZC71 alloy matrix and 12 vol% silicon carbide (SiC) particles were studied using linear polarization resistance, potential-time, potentiodynamic polarization, x-ray diffraction, Rutherford backscattering spectroscopy, and microscopic examination. The coating, typically {approximately}3 {micro}m to 5 {micro}m thick, was composed largely of crystalline magnesium tin oxide (MgSnO{sub 3} {center{underscore}dot} 3H{sub 2}O), and developed by a nucleation and growth process through an initial corrosion film on the substrate. Nucleation probably occurred on regions where a critical concentration of magnesium ions was reached for coating crystals to form. Specific sites of nucleation, such as particles of eutectic phase and of reinforcement, were revealed in some cases, but frequently the precise sites of nucleation were not disclosed. A longer treatment time (at least 35 min) was suggested by polarization resistance data for improved coverage of the substrate than the previously recommended time of 20 min. The coating continuity on the substrates, after a particular time of treatment, depends upon ally composition increasing in order: Mg{sup comm}, 12% (SiC)p/ZC71 alloy MMC, ZC71 alloy, and WE43 alloy. Polarization resistance (R{sub p}) changed systematically with coating development, showing a decrease in R{sub p} in the early stages of the coating process, related to the initial corrosion.

  12. An Investigation of Power Stabilization and Space-Dependent Dynamics of a Nuclear Fluidized-Bed Reactor

    International Nuclear Information System (INIS)

    Pain, Christopher C.; Eaton, Matthew D.; Gomes, Jefferson L.M.A.; Oliveira, Cassiano R.E. de; Umpleby, Adrian P.; Ziver, Kemal; Ackroyd, Ron T.; Miles, Bryan; Goddard, Antony J.H.; Dam, H. van; Hagen, T.H.J.J. van der; Lathouwers, D.

    2003-01-01

    Previous work into the space-dependent kinetics of the conceptual nuclear fluidized bed has highlighted the sensitivity of fission power to particle movements within the bed. The work presented in this paper investigates a method of stabilizing the fission power by making it less sensitive to fuel particle movement. Steady-state neutronic calculations are performed to obtain a suitable design that is stable to radial and axial fuel particle movements in the bed. Detailed spatial/temporal simulations performed using the finite element transient criticality (FETCH) code investigate the dynamics of the new reactor design. A dual requirement of the design is that it has a moderate power output of ∼300 MW(thermal)

  13. Overview: recognizing the problem of magnesium deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Seelig, M.S.

    1988-01-01

    The magnesium content of the usual American diet is less than the recommended dietary allowance. Excesses of some macro- and micro-nutrients interact with Mg, increasing its requirements. Marginal deficiency of Mg is not associated with hypomagnesemia, is not characterized by typical manifestations, as is thus difficult to diagnose. Serum or plasma Mg levels are held within narrow limits unless tissue levels are very low, or renal function is poor. Vulnerability to Mg deficiency increases during growth and development, pregnancy, when under physical or psychological stress, and during illness or its treatment that interferes with absorption or causes loss of Mg. Evidence of biochemical changes of early Mg deficiency is rarely sought, although the roles of Mg in many enzyme systems are recognized. The effects of Mg deficiency on metabolism, even in disorders caused by vitamin dependencies in which Mg is a co-factor, are largely unexplored. Deficiency of Mg is diagnosed confidently when the laboratory reports hypomagnesemia in patients with convulsions or arrhythmias. Without these signs, Mg levels are not often ordered, even in the presence of neuromuscular irritability such as respond to Mg repletion. Because Mg supplementation or Mg-sparing drugs protect against premature or ectopic heart beats and sudden death, to which diuretic-treated hypertensive patients are at risk, it is increasingly being advised that their Mg status be determined.

  14. Radiometric Testing of Magnesium Diboride Array (MDA)

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective is to develop a 2-Dimensional Far Infra-Red Magnesium Diboride Array (2D FIR MDA) to use in NASA's future planetary exploration instruments. The array...

  15. In Vivo and In Silico Investigation Into Mechanisms of Frequency Dependence of Repolarization Alternans in Human Ventricular Cardiomyocytes.

    Science.gov (United States)

    Zhou, Xin; Bueno-Orovio, Alfonso; Orini, Michele; Hanson, Ben; Hayward, Martin; Taggart, Peter; Lambiase, Pier D; Burrage, Kevin; Rodriguez, Blanca

    2016-01-22

    Repolarization alternans (RA) are associated with arrhythmogenesis. Animal studies have revealed potential mechanisms, but human-focused studies are needed. RA generation and frequency dependence may be determined by cell-to-cell variability in protein expression, which is regulated by genetic and external factors. To characterize in vivo RA in human and to investigate in silico using human models, the ionic mechanisms underlying the frequency-dependent differences in RA behavior identified in vivo. In vivo electrograms were acquired at 240 sites covering the epicardium of 41 patients at 6 cycle lengths (600-350 ms). In silico investigations were conducted using a population of biophysically detailed human models incorporating variability in protein expression and calibrated using in vivo recordings. Both in silico and in vivo, 2 types of RA were identified, with Fork- and Eye-type restitution curves, based on RA persistence or disappearance, respectively, at fast pacing rates. In silico simulations show that RA are strongly correlated with fluctuations in sarcoplasmic reticulum calcium, because of strong release and weak reuptake. Large L-type calcium current conductance is responsible for RA disappearance at fast frequencies in Eye-type (30% larger in Eye-type versus Fork-type; Psilico, 2 types of RA are identified, with RA persistence/disappearance as frequency increases. In silico, L-type calcium current and Na(+)/Ca(2+) exchanger current determine RA human cell-to-cell differences through intracellular and sarcoplasmic reticulum calcium regulation. © 2015 The Authors.

  16. Extracellular magnesium decreases the secretory response of rat peritoneal mast cells to compound 48/80 in vitro

    DEFF Research Database (Denmark)

    Bertelsen, Niels Haldor; Johansen, Torben

    1991-01-01

    Exposure of rat peritoneal mast cells to magnesium in the absence of extracellular calcium resulted in a time- and dose-dependent decrease in the secretory response induced by compound 48/80. The decrease was prevented by a low extracellular concentration of calcium. Furthermore, the decreased se...... that magnesium may decrease the secretory response by displacing the cellular calcium which is utilized in stimulus-secretion coupling....

  17. Magnesium-titanium alloys for biomedical applications

    Science.gov (United States)

    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

  18. Can magnesium sulfate therapy impact lactogenesis?

    Science.gov (United States)

    Haldeman, W

    1993-12-01

    This case report describes a patient who ingested magnesium sulfate (MgSO4) for approximately four days as a treatment for pregnancy-induced hypertension. Stage II lactogenesis was delayed until the tenth postpartum day at which point the patient's breasts became fully engorged. No explanation for this delay was found, other than the possibility that magnesium sulfate treatment impeded lactogenesis. Implications for professionals who care for lactating women are discussed.

  19. Properties isotropy of magnesium alloy strip workpieces

    OpenAIRE

    Р. Кавалла; В. Ю. Бажин

    2016-01-01

    The paper discusses the issue of obtaining high quality cast workpieces of magnesium alloys produced by strip roll-casting. Producing strips of magnesium alloys by combining the processes of casting and rolling when liquid melt is fed continuously to fast rolls is quite promising and economic. In the process of sheet stamping considerable losses of metal occur on festoons formed due to anisotropy of properties of foil workpiece, as defined by the macro- and microstructure and modes of rolling...

  20. Statistical approach to study of lithium magnesium metaborate glasses

    Directory of Open Access Journals (Sweden)

    Nedyalkova Miroslava

    2017-03-01

    Full Text Available Alkali borate glasses and alkaline earth borate glasses are commonly used materials in the field of optoelectronics. Infrared (FTIR and Raman spectroscopy are valuable tools for structural investigation of borate glass networks. The compositional and structural variety of lithium magnesium metaborate glasses is usually determined by traditional instrumental methods. In this study a data set is classified by structural and physicochemical parameters (FTIR, Raman spectra, glass transition temperature-Tg. Characterisation of magnesium containing metaborate glasses by multivariate statistics (hierarchical cluster analysis to reveal potential relationships (similarity or dissimilarity between the type of glasses included in the data set using specific structural features available in the literature is conducted. The clustering of the glass objects indicates a good separation of different magnesium containing borate glass compositions. The grouping of variables concerning Tg and structural data for BO3 and BO4 linkage confirms that BO4/BO3 ratios strongly affect Tg. Additionally, patterns of similarity could be detected not only between the glass composition but also between the features (variables describing the glasses. The proposed approach can be further used as an expert tool for glass properties prediction or fingerprinting (identification of unknown compositions.

  1. Porous magnesium-based scaffolds for tissue engineering

    International Nuclear Information System (INIS)

    Yazdimamaghani, Mostafa; Razavi, Mehdi; Vashaee, Daryoosh; Moharamzadeh, Keyvan; Boccaccini, Aldo R.; Tayebi, Lobat

    2017-01-01

    Significant amount of research efforts have been dedicated to the development of scaffolds for tissue engineering. Although at present most of the studies are focused on non-load bearing scaffolds, many scaffolds have also been investigated for hard tissue repair. In particular, metallic scaffolds are being studied for hard tissue engineering due to their suitable mechanical properties. Several biocompatible metallic materials such as stainless steels, cobalt alloys, titanium alloys, tantalum, nitinol and magnesium alloys have been commonly employed as implants in orthopedic and dental treatments. They are often used to replace and regenerate the damaged bones or to provide structural support for healing bone defects. Among the common metallic biomaterials, magnesium (Mg) and a number of its alloys are effective because of their mechanical properties close to those of human bone, their natural ionic content that may have important functional roles in physiological systems, and their in vivo biodegradation characteristics in body fluids. Due to such collective properties, Mg based alloys can be employed as biocompatible, bioactive, and biodegradable scaffolds for load-bearing applications. Recently, porous Mg and Mg alloys have been specially suggested as metallic scaffolds for bone tissue engineering. With further optimization of the fabrication techniques, porous Mg is expected to make a promising hard substitute scaffold. The present review covers research conducted on the fabrication techniques, surface modifications, properties and biological characteristics of Mg alloys based scaffolds. Furthermore, the potential applications, challenges and future trends of such degradable metallic scaffolds are discussed in detail. - Highlights: • A porous 3D material provides the required pathways for cells to grow, proliferate, and differentiate • Porous magnesium and Mg alloys could be used as load-bearing scaffolds • Porous magnesium and Mg alloys are good

  2. Effect of heat treatment and number of passes on the microstructure and mechanical properties of friction stir processed AZ91C magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Dadashpour, M.; Yeşildal, R. [University of Ataturk, Erzurum (Turkmenistan); Mostafapour, A.; Rezazade, V. [University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2016-02-15

    In this paper, the effect of heat treatment and number of passes on microstructure and mechanical properties of friction stir processed AZ91C magnesium alloy samples were investigated. From six samples of as-cast AZ91C magnesium alloy, three plates were pre-heated at temperature of 375°C for 3 hours, and then were treated at temperature of 415°C for 18 hours and finally were cooled down in air. Three plates were relinquished without heat treatment. 8 mm thick as-cast AZ91C magnesium alloy plates were friction stir processed at constant traverse speed of 40 mm/min and tool rotation speed of 1250 rpm. After process, microstructural characterization of samples was analyzed using optical microscopy and tensile and Vickers hardness tests were performed. It was found that heat treated samples had finer grains, higher hardness, improved tensile strength and elongation relative to non-heat treated ones. As the number of passes increased, higher UTS and TE were achieved due to finer grains and more dissolution of β phase (Mg17Al12). The micro-hardness characteristics and tensile improvement of the friction stir processed samples depend significantly on grain size, removal of voids and porosities and dissolution of β phase in the stir zone.

  3. ISOCHORIC HEAT CAPACITY OF 1% AQUEOUS SOLUTION OF MAGNESIUM CHLORIDE

    OpenAIRE

    V. I. Dvoryanchikov; D. K. Djavatov; G. A. Rabadanov; E. G. Iskenderov; D. P. Shikhakhmedova

    2016-01-01

    Aim. The aim is to conduct an experimental study of isochoric heat capacity of 1% aqueous solution of magnesium chloride along the phase boundary curve.Method. In order to determine the isochoric heat capacity at the phase boundary curve we used the adiabatic calorimeter of KH. I. Amirkhanov.Results. Results of the study of the isochoric heat capacity depending on the temperature are given in tables and figures; the findings are compared with those of other researchers. When evaluating a comp...

  4. A comparison of corrosion inhibition of magnesium aluminum and zinc aluminum vanadate intercalated layered double hydroxides on magnesium alloys

    Science.gov (United States)

    Guo, Lian; Zhang, Fen; Lu, Jun-Cai; Zeng, Rong-Chang; Li, Shuo-Qi; Song, Liang; Zeng, Jian-Min

    2018-04-01

    The magnesium aluminum and zinc aluminum layered double hydroxides intercalated with NO3 -(MgAl-NO3-LDH and ZnAl-NO3-LDH) were prepared by the coprecipitation method, and the magnesium aluminum and the zinc aluminum layered double hydroxides intercalated with VO x -(MgAl-VO x -LDH and ZnAl-VO x -LDH) were prepared by the anion-exchange method. Morphologies, microstructures and chemical compositions of LDHs were investigated by SEM, EDS, XRD, FTIR, Raman and TG analyses. The immersion tests were carried to determine the corrosion inhibition properties of MgAl-VO x -LDH and ZnAl-VO x -LDH on AZ31 Mg alloys. The results showed that ZnAl-VO x -LDH possesses the best anion-exchange and inhibition abilities. The influence of treatment parameters on microstructures of LDHs were discussed. Additionally, an inhibition mechanism for ZnAl-VO x -LDH on the AZ31 magnesium alloy was proposed and discussed.

  5. Magnesium-phosphate-glass cements with ceramic-type properties

    Science.gov (United States)

    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.

  6. Magnesium phosphate glass cements with ceramic-type properties

    Science.gov (United States)

    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.

  7. ISOCHORIC HEAT CAPACITY OF 1% AQUEOUS SOLUTION OF MAGNESIUM CHLORIDE

    Directory of Open Access Journals (Sweden)

    V. I. Dvoryanchikov

    2016-01-01

    Full Text Available Aim. The aim is to conduct an experimental study of isochoric heat capacity of 1% aqueous solution of magnesium chloride along the phase boundary curve.Method. In order to determine the isochoric heat capacity at the phase boundary curve we used the adiabatic calorimeter of KH. I. Amirkhanov.Results. Results of the study of the isochoric heat capacity depending on the temperature are given in tables and figures; the findings are compared with those of other researchers. When evaluating a complex system, we ought not to evaluate its effectiveness on the basis of only one criterion, even a very important, in this case must take into account the requirements of the technical, economic, environmental and of other natures.Conclusions. When solving optimization problems of efficiency in geothermal energy it is necessary to take into account the fact of the temperature dependence of the heat and density. The temperature dependence of the density and heat capacity in the calculations significantly affect the value of the efficiency criterion to be taken into account, otherwise the calculation error can be up to 20%. The data obtained from the isochoric heat capacity of aqueous solutions of magnesium chloride is compared with the data for water and aqueous solutions of NaCl and NaOH, obtained previously, which may be represented as a model of geothermal and sea water.

  8. Cooperation between Magnesium and Metabolite Controls Collapse of the SAM-I Riboswitch.

    Science.gov (United States)

    Roy, Susmita; Onuchic, José N; Sanbonmatsu, Karissa Y

    2017-07-25

    The S-adenosylmethionine (SAM)-I riboswitch is a noncoding RNA that regulates the transcription termination process in response to metabolite (SAM) binding. The aptamer portion of the riboswitch may adopt an open or closed state depending on the presence of metabolite. Although the transition between the open and closed states is critical for the switching process, its atomistic details are not well understood. Using atomistic simulations, we calculate the effect of SAM and magnesium ions on the folding free energy landscape of the SAM-I riboswitch. These molecular simulation results are consistent with our previous wetlab experiments and aid in interpreting the SHAPE probing measurements. Here, molecular dynamics simulations explicitly identify target RNA motifs sensitive to magnesium ions and SAM. In the simulations, we observe that, whereas the metabolite mostly stabilizes the P1 and P3 helices, magnesium serves an important role in stabilizing a pseudoknot interaction between the P2 and P4 helices, even at high metabolite concentrations. The pseudoknot stabilization by magnesium, in combination with P1 stabilization by SAM, explains the requirement of both SAM and magnesium to form the fully collapsed metabolite-bound closed state of the SAM-I riboswitch. In the absence of SAM, frequent open-to-closed conformational transitions of the pseudoknot occur, akin to breathing. These pseudoknot fluctuations disrupt the binding site by facilitating fluctuations in the 5'-end of helix P1. Magnesium biases the landscape toward a collapsed state (preorganization) by coordinating pseudoknot and 5'-P1 fluctuations. The cooperation between SAM and magnesium in stabilizing important tertiary interactions elucidates their functional significance in transcription regulation. Published by Elsevier Inc.

  9. "Changes in cartilage of rats after treatment with Quinolone and in Magnesium-deficient diet "

    Directory of Open Access Journals (Sweden)

    Shakibaei M

    2002-07-01

    Full Text Available Ultrastructural changes in immature articular carilage were studied after treatment of 5-weeks-old rats with ofloxacin, a fluoroquinolone, and in magnesium deficiency.We concluded that quinolone-induced arthropathy is probably due to chelation of functionally available magnesium in joint cartilage as magnesium deficiency in joint cartilage could impair chondrocyte-matrix- interaction which is mediated by cation-dependent integrin-receptors of the β1-subfamily. With immuno-histochemical methods using monoclonal and polyclonal antibodies we showed that B1 integrins were expressed in rat joint cartilage. Joint cartilage lesions were detected in ofloxacin-treated and magnesium-deficient rats. Lesions were more pronounced in the quinolone-treated group. Expression of several integrins was reduced in the vicinity of lesions after oral treatment with 2×600 mg ofloxacin/kg body wt for one day. Gross-structural lesions (e.g. cleft formation, unmasked collagen fibres in magnesium deficient rats were very similar but changes in intergrin expression were less pronounced. Alterations observed on the ultrastructural level showed striking similarities in magnesium-deficient rats and in rats treated with single doses of 600 mg ofloxacin per kg body wt.Typical observation were: bundle shaped, electron-dense aggregates on the surface and in the cytoplasm of chondrocytes, detachement of the cell membrance from the matrix and necrotic chondrocytes, reduced synthesis and/or reduced of extracellular matrix and swelling of cell organelles such as mitochondria.The results of this study confirm our previously reported finding that quinolone-induced arthropathy probably is caued by a reduction of functionally available magnesium (ionized Mg2+ in cartilage. Furthermore, they provide a basis for aimed studies with human cartilage samples from quinolone-treated patients which might be available postmortal or after hip replacement surgery

  10. Investigation of temperature dependence of fracture toughness in high-dose HT9 steel using small-specimen reuse technique

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Jong-Hyuk; Byun, Thak Sang; Maloy, Stuart A.; Toloczko, Mychailo B.

    2014-01-01

    The temperature dependence of fracture toughness in HT9 steel irradiated to 3–145 dpa at 380–503 degrees*C was investigated using miniature three-point bend (TPB) fracture specimens. A miniature-specimen reuse technique has been established: the tested halves of subsize Charpy impact specimens with dimensions of 27 mm *3mm* 4 mm were reused for this fracture test campaign by cutting a notch with a diamond-saw in the middle of each half, and by fatigue-precracking to generate a sharp crack tip. It was confirmed that the fracture toughness of HT9 steel in the dose range depends more strongly on the irradiation temperature than the irradiation dose. At an irradiation temperature <430 *degreesC, the fracture toughness of irradiated HT9 increased with the test temperature, reached an upper shelf of 180—200 MPa*m^.5 at 350–450 degrees*C, and then decreased with the test temperature. At an irradiation temperature >430 degrees*C, the fracture toughness was nearly unchanged up to about 450 *degreesC and decreased slowly with test temperatures in a higher temperature range. Such a rather monotonic test temperature dependence after high-temperature irradiation is similar to that observed for an archive material generally showing a higher degree of toughness. A brittle fracture without stable crack growth occurred in only a few specimens with relatively lower irradiation and test temperatures. In this discussion, these TPB fracture toughness data are compared with previously published data from 12.7 mm diameter disc compact tension (DCT) specimens.

  11. Investigation of temperature dependence of fracture toughness in high-dose HT9 steel using small-specimen reuse technique

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Jong-Hyuk [KAERI; Byun, Thak Sang [ORNL; Maloy, S [Los Alamos National Laboratory (LANL); Toloczko, M [Pacific Northwest National Laboratory (PNNL)

    2014-01-01

    The temperature dependence of fracture toughness in HT9 steel irradiated to 3 145 dpa at 380 503 C was investigated using miniature three-point bend (TPB) fracture specimens. A miniature-specimen reuse technique has been established: the tested halves of subsize Charpy impact specimens with dimensions of 27 mm 3mm 4 mm were reused for this fracture test campaign by cutting a notch with a diamond-saw in the middle of each half, and by fatigue-precracking to generate a sharp crack tip. It was confirmed that the fracture toughness of HT9 steel in the dose range depends more strongly on the irradiation temperature than the irradiation dose. At an irradiation temperature <430 C, the fracture toughness of irradiated HT9 increased with the test temperature, reached an upper shelf of 180 200 MPa ffiffiffiffiffi m p at 350 450 C, and then decreased with the test temperature. At an irradiation temperatureP430 C, the fracture toughness was nearly unchanged up to about 450 C and decreased slowly with test temperatures in a higher temperature range. Such a rather monotonic test temperature dependence after high-temperature irradiation is similar to that observed for an archive material generally showing a higher degree of toughness. A brittle fracture without stable crack growth occurred in only a few specimens with relatively lower irradiation and test temperatures. In this discussion, these TPB fracture toughness data are compared with previously published data from 12.7 mm diameter disc compact tension (DCT) specimens.

  12. Investigation of temperature dependence of fracture toughness in high-dose HT9 steel using small-specimen reuse technique

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Jong-Hyuk, E-mail: jhbaek@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Byun, Thak Sang [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Maloy, Start A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Toloczko, Mychailo B. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2014-01-15

    The temperature dependence of fracture toughness in HT9 steel irradiated to 3–145 dpa at 380–503 °C was investigated using miniature three-point bend (TPB) fracture specimens. A miniature-specimen reuse technique has been established: the tested halves of subsize Charpy impact specimens with dimensions of 27 mm × 3 mm × 4 mm were reused for this fracture test campaign by cutting a notch with a diamond-saw in the middle of each half, and by fatigue-precracking to generate a sharp crack tip. It was confirmed that the fracture toughness of HT9 steel in the dose range depends more strongly on the irradiation temperature than the irradiation dose. At an irradiation temperature <430 °C, the fracture toughness of irradiated HT9 increased with the test temperature, reached an upper shelf of 180–200MPa√(m) at 350–450 °C, and then decreased with the test temperature. At an irradiation temperature ⩾430 °C, the fracture toughness was nearly unchanged up to about 450 °C and decreased slowly with test temperatures in a higher temperature range. Such a rather monotonic test temperature dependence after high-temperature irradiation is similar to that observed for an archive material generally showing a higher degree of toughness. A brittle fracture without stable crack growth occurred in only a few specimens with relatively lower irradiation and test temperatures. In this discussion, these TPB fracture toughness data are compared with previously published data from 12.7 mm diameter disc compact tension (DCT) specimens.

  13. Investigation of temperature dependence of fracture toughness in high-dose HT9 steel using small-specimen reuse technique

    Science.gov (United States)

    Baek, Jong-Hyuk; Byun, Thak Sang; Maloy, Start A.; Toloczko, Mychailo B.

    2014-01-01

    The temperature dependence of fracture toughness in HT9 steel irradiated to 3-145 dpa at 380-503 °C was investigated using miniature three-point bend (TPB) fracture specimens. A miniature-specimen reuse technique has been established: the tested halves of subsize Charpy impact specimens with dimensions of 27 mm × 3 mm × 4 mm were reused for this fracture test campaign by cutting a notch with a diamond-saw in the middle of each half, and by fatigue-precracking to generate a sharp crack tip. It was confirmed that the fracture toughness of HT9 steel in the dose range depends more strongly on the irradiation temperature than the irradiation dose. At an irradiation temperature test temperature, reached an upper shelf of 180-200 MPa √{m} at 350-450 °C, and then decreased with the test temperature. At an irradiation temperature ⩾430 °C, the fracture toughness was nearly unchanged up to about 450 °C and decreased slowly with test temperatures in a higher temperature range. Such a rather monotonic test temperature dependence after high-temperature irradiation is similar to that observed for an archive material generally showing a higher degree of toughness. A brittle fracture without stable crack growth occurred in only a few specimens with relatively lower irradiation and test temperatures. In this discussion, these TPB fracture toughness data are compared with previously published data from 12.7 mm diameter disc compact tension (DCT) specimens.

  14. Leaf Senescence by Magnesium Deficiency

    Directory of Open Access Journals (Sweden)

    Keitaro Tanoi

    2015-12-01

    Full Text Available 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.

  15. Numerical investigation of the threshold intensity dependence on gas pressure in the breakdown of xenon by different laser wavelengths

    Science.gov (United States)

    Gamal, Yosr E. E.-D.; Abd El Hameid Mahmoud, Mohamed; Dawood, Nagia D. A.

    2014-07-01

    We report a theoretical analysis of the measurements that carried out to study the breakdown of xenon gas over a wide pressure range induced by laser source operating at different wavelengths. The study provided an investigation of the effect of laser wavelength as well as gas pressure on the physical processes associated with this phenomenon. To this aim a modified electron cascade model is applied. The model based on the numerical solution of the time dependent Boltzmann equation for the electron energy distribution function (EEDF) simultaneously with a set of rate equations which describe the rate of change of the formed excited states population. Comparison between the calculated and measured threshold intensities for the experimentally tested laser wavelengths and gas pressure range is obtained. Furthermore computations of the EEDF and its parameters showed the actual correlation between the gain and loss processes which determine the threshold breakdown intensity of xenon and the two experimentally tested parameters; laser wavelength and gas pressure.

  16. Time-dependent density-functional-theory investigation of the collisions of protons and α particles with uracil and adenine

    Science.gov (United States)

    Covington, Cody; Hartig, Kara; Russakoff, Arthur; Kulpins, Ryan; Varga, Kálmán

    2017-05-01

    Time-dependent density-functional theory was employed to study the effects of proton and α -particle radiation on uracil and adenine. This method has the advantage of treating nuclear motion and electronic motion simultaneously, allowing for the study of electronic excitation, charge transfer, ionization, and nuclear motion. Particle energies were surveyed in the range of 15-500 keV for protons and 100-2000 keV for α particles in conjunction with impact points both on and off carbon bonds in order to investigate the electron and nuclear dynamics of irradiated molecules and the form and quantity of transferred energy. The stopping power, energy transferred, and ionization were found, and the relationship between incident particle energy and electron density of the target molecule was characterized for proton and α -particle radiation incident on adenine and uracil.

  17. Investigation of the temperature dependence of the Bose condensate density in helium 4 in relation to the superconductivity phenomenon

    International Nuclear Information System (INIS)

    Dokukin, E.B.; Kozlov, Zh.A.; Parfenov, V.A.; Puchkov, A.V.

    1978-01-01

    The experimental results on the relative-density temperature dependence of the Bose-condensate (BC) and on the mean kinetic energy per atom in a liquid hellium-4 are discussed. The investigation has been carried out by studying the spectra of inelastic neutron scattering at the momentum transfers k=12 - 14 A -1 at the temperatures of 1.2 -4.2 K. The experimental data have been analyzed by means of the two-gaussian and one-gaussian models. The BC relative density is estimated by the method of two-gaussian expansion of spectra of neutrons scattered by liquid helium. The temperature dependence has a singularity at T 0 . BC is observed at T 0 and none is observed at T>T 0 within the accuracy of an experiment and mathematical data processing. The BC relative density at T→0 makes up 0.022+-0.002, the temperature of the Bose condensation coinciding with that of the lambda-transition

  18. Empirical investigation on the dependence of TCP downstream throughput on SNR in an IEEE802.11b WLAN system

    Directory of Open Access Journals (Sweden)

    Ikponmwosa Oghogho

    2017-04-01

    Full Text Available The dependence of TCP downstream throughput (TCPdownT on signal to noise ratio (SNR in an IEEE802.11b WLAN system was investigated in various environments and varieties of QoS traffic. TCPdownT was measured for various SNR observed. An Infrastructure based IEEE802.11b WLAN system having networked computers on which measurement software were installed, was set up consecutively in various environments (open corridor, small offices with block walls and plaster boards and free space. Empirical models describing TCPdownT against SNR for different signal ranges (all ranges of signals, strong signals only, grey signals only and weak signals only were statistically generated and validated. As the SNR values changed from high (strong signals through low (grey signals to very low (weak signals, our results show a strong dependence of TCPdownT on the received SNR. Our models showed lower RMS errors when compared with other similar models. We observed RMS errors of 0.6734791 Mbps, 0.472209 Mbps, 0.9111563 Mbps and 0.5764460 Mbps for general (all SNR model, strong signals model, grey signals model and Weak signals model respectively. Our models will provide researchers and WLAN systems users with a tool to estimate the TCP downstream throughput in a real network in various environments by monitoring the received SNR.

  19. A numerical investigation of the dependence of the threshold irradiance on the wavelength in laser-induced breakdown in

    Science.gov (United States)

    Gamal, Yosr E.; Shafik, M. S.; Daoud, Jamal M.

    1999-02-01

    Studies of laser-induced breakdown in molecular nitrogen were carried out to investigate the dependence of the threshold irradiance on the wavelength at various pressures. The analysis was based on the numerical solution of the time-dependent Boltzmann equation for the electron energy distribution function (EEDF) and a set of rate equations describing the rate of change of the excited states population. The rate coefficients and cross-sections as functions of the electron energy were introduced into this analysis in order to probe the exact contribution of each physical process to the breakdown phenomenon. The calculations were performed under the experimental conditions of Davis et al. In this experiment the breakdown of nitrogen was measured at wavelengths of 1064, 532, 355 and 266 nm, over gas pressures in the range 25-760 Torr, with laser irradiances in the range to . The computed thresholds were found to be in good agreement with the measured ones at all wavelengths. The calculated EEDF and its parameters showed that, at nm, vibrational losses are dominant. Collisional ionization of ground and excited state molecules was found to make a minor contribution to the breakdown phenomenon at 532, 355 and 266 nm. However, the contribution to this process at 1064 nm was more effective. Therefore, the breakdown phenomenon proceeds via an electron-cascade process that converts the molecules only into the excited states, whence multiphoton ionization plays its role.

  20. Energy response of graphite-mixed magnesium borate TLDs to low energy x-rays

    DEFF Research Database (Denmark)

    Pelliccioni, M.; Prokic, M.; Esposito, A.

    1991-01-01

    Graphite-mixed sintered magnesium borate TL dosemeters are attractive for beta/gamma dosimetry because they combine a low energy dependence to beta-rays with near tissue or air equivalence to photon irradiations and a high sensitivity. In this paper results from the experimental measurements...

  1. Correlation of magnesium intake with metabolic parameters, depression and physical activity in elderly type 2 diabetes patients: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Huang Jui-Hua

    2012-06-01

    Full Text Available Abstract Background Type 2 diabetes mellitus is a major global public health problem in the worldwide and is increasing in aging populations. Magnesium intake may be one of the most important factors for diabetes prevention and management. Low magnesium intake may exacerbate metabolic abnormalities. In this study, the relationships of magnesium intake with metabolic parameters, depression and physical activity in elderly patients with type 2 diabetes were investigated. Methods This cross-sectional study involved 210 type 2 diabetes patients aged 65 years and above. Participants were interviewed to obtain information on lifestyle and 24-hour dietary recall. Assessment of depression was based on DSM-IV criteria. Clinical variables measured included anthropometric measurements, blood pressure, and biochemical determinations of blood and urine samples. Linear regression was applied to determine the relationships of magnesium intake with nutritional variables and metabolic parameters. Results Among all patients, 88.6% had magnesium intake which was less than the dietary reference intake, and 37.1% had hypomagnesaemia. Metabolic syndromes and depression were associated with lower magnesium intake (p  0.05. A positive relationship was found between magnesium intake and HDL-cholesterol (p = 0.005. Magnesium intake was inversely correlated with triglyceride, waist circumference, body fat percent and body mass index (p p for trend = 0005. Waist circumference, body fat percentage, and body mass index were significantly lower with increase quartile of magnesium intake (p for trend p for trend  Conclusions The majority of elderly type 2 diabetes who have low magnesium intake may compound this deficiency with metabolic abnormalities and depression. Future studies should determine the effects of increased magnesium intake or magnesium supplementation on metabolic control and depression in elderly people with type 2 diabetes.

  2. SU-E-T-515: Investigating the Linear Energy Transfer Dependency of Different PRESAGE Formulations in a Proton Beam

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, M [University of Texas MD Anderson Cancer Center, Houston, TX (United States); Alqathami, M; Blencowe, A [The University of South Australia, South Australia, SA (Australia); Ibbott, G [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose Previous studies have reported an under-response of PRESAGE in a proton beam as a Result of the extremely high LET in the distal end of the spread out Bragg peak (SOBP). This work is a preliminary investigation to quantify the effect of the formulation, specifically the concentration of halocarbon radical initiator relative to leuco dye, on radical recombination resulting in LET dependence. Methods The traditional PRESAGE formulation developed by Heuris Pharma was altered to constitute radical initiator concentrations of 5, 15, and 30% (low, medium, and high) by weight with all other components balanced to maintain proportionality. Chloroform was specifically examined in this study and all dosimeters were made in-house. Cylindrical PRESAGE dosimeters (3.5cm diameter and 6cm length) were made for each formulation and irradiated by a 200-MeV proton beam to 500 cGy across a 2cm SOBP. Dosimeters were read out using the DMOS optical-CT scanner. The dose distributions were analyzed and dose profiles were used to compare the relative dose response to find the stability across the high-LET region of the SOBP. LET dependence was measured by the variation to ion chamber measurements for the final 25% of the SOBP (∼0.5cm) prior to the distal-90 of each profile. Results Relative to ion chamber data, all PRESAGE dosimeters showed an under-response at the distal end of the SOBP. The medium concentration formulation matched most closely with an average 8.3% under-response closely followed by the low concentration at 12.2% and then the high concentration at 22.8%. In all three cases, the highest points of discrepancy were in the distal most regions. Conclusion The radical initiator concentration in PRESAGE can be tailored to reduce the LET dependence in a proton beam. This warrants further study to quantify comprehensively the effect of concentration of different halocarbon radical initiators on LET dependency. Grant number 5RO1CA100835.

  3. An alternative magnesium-based root canal disinfectant: Preliminary study of its efficacy against Enterococcus faecalis and Candida albicans in vitro

    OpenAIRE

    Lin Zhu; Peng Wan; Jiaohong Duan; Lili Tan; Ke Yang

    2014-01-01

    Organisms invading root canal systems result in serious pulpal and periapical disease. To eliminate microorganisms and restrain secondary infections, dental materials with antibacterial properties are urgently needed in endodontics. Magnesium is considered as a promising biodegradable and biocompatible implant material. However, there are barely researches about its application in endodontic therapy. This work investigated the in vitro efficacy of magnesium powder against Enterococcus faecali...

  4. Effects of calcium magnesium acetate on the combustion of coal-water slurries

    Energy Technology Data Exchange (ETDEWEB)

    Levendis, Y.A.

    1990-01-01

    The general objective of the project is to investigate the combustion behavior of single and multiple Coal-Water Slurry particles burning at high temperature environments. Both uncatalyzed as well as catalyzed CWS drops with Calcium Magnesium Acetate (CMA) catalyst will be investigated. Emphasis will also be given in the effects of CMA on the sulfur capture during combustion. 10 figs.

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

    Science.gov (United States)

    Choi, Mi-Kyeong; Bae, Yun Jung

    2015-01-01

    Magnesium is known to lower the risk of cardiovascular disease. However, studies on its relationship with hypertension, a single and common cause of various chronic diseases, are limited and their findings are not consistent. The purpose of the present study is to identify the relationship between magnesium intake and high blood pressure (HBP) risk in Koreans. This research is a cross-sectional study based on the 2007~2009 Korean National Health and Nutritional Examination Survey data. This study investigated 11,685 adults aged over 20 to examine their general characteristics, anthropometry and blood pressure. Daily magnesium intake was analyzed using the 24-hour dietary recall method. To calculate the odds ratio (OR) of HBP risk (130/85 mmHg or over) according to the quartile of magnesium intake (mg/1000 kcal) together with its 95% confidence interval (CI), multivariable logistic regression analysis was performed. No significant association between dietary magnesium intake and the risk of HBP was found. In obese women, particularly, after adjusting relevant factors, the adjusted odds ratio of HBP prevalence in the highest magnesium intake quartile was 0.40 compared with the lowest magnesium intake quartile (95% CI = 0.25~0.63, P for trend = 0.0014). Women, especially obese women, were found to have a negative relationship of magnesium intake with HBP. The present results indicate that sufficient magnesium intake could be useful in decreasing the high blood pressure risk of obese women.

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

    Science.gov (United States)

    Choi, Mi-Kyeong; Bae, Yun Jung

    2015-01-01

    Background Magnesium is known to lower the risk of cardiovascular disease. However, studies on its relationship with hypertension, a single and common cause of various chronic diseases, are limited and their findings are not consistent. The purpose of the present study is to identify the relationship between magnesium intake and high blood pressure (HBP) risk in Koreans. Methods This research is a cross-sectional study based on the 2007~2009 Korean National Health and Nutritional Examination Survey data. This study investigated 11,685 adults aged over 20 to examine their general characteristics, anthropometry and blood pressure. Daily magnesium intake was analyzed using the 24-hour dietary recall method. To calculate the odds ratio (OR) of HBP risk (130/85 mmHg or over) according to the quartile of magnesium intake (mg/1000kcal) together with its 95% confidence interval (CI), multivariable logistic regression analysis was performed. Results No significant association between dietary magnesium intake and the risk of HBP was found. In obese women, particularly, after adjusting relevant factors, the adjusted odds ratio of HBP prevalence in the highest magnesium intake quartile was 0.40 compared with the lowest magnesium intake quartile (95% CI = 0.25~0.63, P for trend = 0.0014). Women, especially obese women, were found to have a negative relationship of magnesium intake with HBP. Conclusions The present results indicate that sufficient magnesium intake could be useful in decreasing the high blood pressure risk of obese women. PMID:26075385

  7. Magnesium-Molybate Compounds as Matrix for 99Mo/99mTc Generators

    Directory of Open Access Journals (Sweden)

    Fabiola Monroy-Guzman

    2011-01-01

    Full Text Available This work reports the preparation of a 99mTc generator based on conversion of 99Mo produced by neutron irradiation, into insoluble magnesium 99Mo-molybdates compounds as matrix. The effect of magnesium salt types and concentration, Mg:Mo molar ratios, pH of molybdate solutions, eluate volume as well as the addition order of molybdate and magnesium solutions’ influences on the final 99mTc were evaluated. Polymetalates and polymolybdates salts either crystallized or amorphous were obtained depending on the magnesium salt and Mg:Mo molar ratio used in matrix preparation. 99Mo/99mTc generator production based on magnesium-99Mo molybdate compounds allow reduction of preparation time and eliminates the use of specialized installations. The best generator performances were attained using matrices prepared from 0.1 mol/L MgCl2·6H2O solutions, ammonium molybdate solutions at pH 7 and at a Mg:Mo molar ratio of 1:1.

  8. Microbiota of high-pressure-processed Serrano ham investigated by culture-dependent and culture-independent methods.

    Science.gov (United States)

    Martínez-Onandi, N; Castioni, A; San Martín, E; Rivas-Cañedo, A; Nuñez, M; Torriani, S; Picon, A

    2017-01-16

    The microbiota of Serrano dry-cured ham of different chemical composition, subjected or not to high-pressure processing (HPP), was investigated using culture-dependent and culture-independent methods. Microbial counts were submitted to analysis of variance with physicochemical parameters (a w , NaCl concentration, salt-in-lean ratio and intramuscular fat content) or HPP as main effects. In untreated hams, physicochemical parameters significantly affected counts of aerobic mesophiles, psychrotrophs, and moulds and yeasts. NaCl concentration and fat content influenced the levels of four and three of the five studied microbial groups, respectively, whereas no influence of a w was stated. The HPP treatment had a significant effect on counts of all investigated microbial groups. Culture-independent methods showed the presence of bacteria such as Staphylococcus equorum, Staphylococcus succinus, Bacillus subtilis and Cellulosimicrobium sp., moulds like Penicillium commune, Aspergillus fumigatus, Sclerotinia sclerotiorum, Eurotium athecium and Moniliella mellis, and yeasts like Debaryomyces hansenii and Candida glucosophila. Absence of B. subtilis bands and weaker bands of E. athecium were recorded for HPP-treated hams. The higher microbial levels found in lean ham might result in a quicker deterioration. HPP treatment confirmed its suitability as a procedure to control spoilage microorganisms. DGGE did not seem to be sensitive enough to highlight changes caused by HPP treatment in the microbiota of ham, but contributed to the detection of microbial species not previously found in ham. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Investigations on the mechanism of oxygen-dependent plant processes: ethylene biosynthesis and cyanide-resistant respiration

    International Nuclear Information System (INIS)

    Stegink, S.J.

    1985-01-01

    Two oxygen-dependent plant processes were investigated. A cell-free preparation from pea (Pisum sativum L., cv. Alaska) was used to study ethylene biosynthesis from 1-aminocyclopropane-1-carboxylic acid. Mitochondrial cyanide-resistant respiration was investigated in studies with 14 C-butyl gallate and other respiratory effectors. Ethylene biosynthesis was not due to a specific enzyme, or oxygen radicals. Rather, hydrogen peroxide, generated at low levels, coupled with endogenous manganese produced ethylene. 14 C-butyl gallate bound specifically to mitochondria from cyanide-sensitive and -resistant higher plants and Neurospora crassa mitochondria. The amount of gallate bound was similar for all higher plant mitochondria. Rat liver mitochondria bound very little 14 C-butyl gallate. Plant mitochondria in which cyanide-resistance was induced bound as much 14 C-butyl gallate as before induction. However mitochondria from recently harvested white potato tubers did not bind the gallate. The observations suggest that an engaging factor couples with a gallate binding site in the mitochondrial membrane. With skunk cabbage spadix mitochondria the I 5 0 for antimycin A inhibition of oxygen uptake was decreased by salicylhydroxamic acid pretreatment; this was also true for reverse order additions. No shift was observed with mung bean hypocotyl or Jerusalem artichoke tuber mitochondria

  10. Dietary magnesium intake and the risk of diabetes in the Japanese community: results from the Takayama study.

    Science.gov (United States)

    Konishi, Kie; Wada, Keiko; Tamura, Takashi; Tsuji, Michiko; Kawachi, Toshiaki; Nagata, Chisato

    2017-03-01

    Several experimental studies showed that magnesium intake improved insulin resistance and glucose uptake in diabetes patients. However, epidemiological studies on the association between magnesium intake and diabetes risk have yielded inconsistent results. We investigated whether magnesium intake is related to the risk of developing diabetes in a population-based cohort study in Japan. Study subjects were participants in the Takayama study. A total of 13,525 residents in Takayama City, Japan, responded to a self-administered questionnaire in 1992 and to a follow-up questionnaire seeking information about diabetes in 2002. Magnesium and other nutrient intakes were estimated from a validated food frequency questionnaire administered at the baseline. During a follow-up of 10 years, 438 subjects reported diabetes newly diagnosed by physician. Compared with women in the low quartile of magnesium intake, women in the high quartile were at a significantly reduced risk of diabetes (HR 0.50; 95 % CI 0.30-0.84; P-trend 0.005) after adjustments for covariates. In men, there was no association between magnesium intake and the risk of diabetes. These results suggest that diets with a high intake of magnesium may decrease the risk of diabetes in women.

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

    International Nuclear Information System (INIS)

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

    2009-01-01

    X-ray photoelectron spectroscopy (XPS) was used in order to investigate the correlation between the surface chemistry and the atmospheric corrosion of AZ31, AZ80 and AZ91D magnesium alloys exposed to 98% relative humidity at 50 deg. C. Commercially pure magnesium, used as the reference material, revealed MgO, Mg(OH) 2 and tracers of magnesium carbonate in the air-formed film. For the AZ80 and AZ91D alloys, the amount of magnesium carbonate formed on the surface reached similar values to those of MgO and Mg(OH) 2 . A linear relation between the amount of magnesium carbonate formed on the surface and the subsequent corrosion behaviour in the humid environment was found. The AZ80 alloy revealed the highest amount of magnesium carbonate in the air-formed film and the highest atmospheric corrosion resistance, even higher than the AZ91D alloy, indicating that aluminium distribution in the alloy microstructure influenced the amount of magnesium carbonate formed.

  12. The relationship between serum magnesium levels with childhood obesity and insulin resistance: a review of the literature.

    Science.gov (United States)

    Celik, Nurullah; Andiran, Nesibe; Yilmaz, Ayse Esra

    2011-01-01

    Magnesium, the second most abundant intracellular cation, plays a major role in regulating insulin effect and insulin mediated glucose uptake. It has been shown that serum magnesium levels were negatively correlated with HOMA-IR (homeostasis model of insulin resistance) index. To investigate the relationship between serum magnesium levels with obesity and insulin resistance in childhood. Two hundred and three children and adolescents (117 obese children and 86 controls) were included. Obese cases were also subgrouped according to the presence or absence of insulin resistance (IR) as "IR (+) obese" and "IR (-) obese", respectively. Serum glucose, insulin and magnesium levels were measured after a 12-h fasting at 8-8.30 a.m. We assessed insulin sensitivity by using HOMA-IR index as a surrogate marker of insulin resistance. Serum levels of magnesium were significantly lower in the IR (+) obese group than controls (p = 0.014). At the same time, there was a positive correlation between serum magnesium levels and body mass index-standard deviation score (BMI-SDS) (r = -0.28, p = 0.03) in the IR (-) obese group. Low serum magnesium levels may contribute to the development of insulin resistance in obese children.

  13. Studies on influence of zinc immersion and fluoride on nickel electroplating on magnesium alloy AZ91D

    International Nuclear Information System (INIS)

    Zhang Ziping; Yu Gang; Ouyang Yuejun; He Xiaomei; Hu Bonian; Zhang Jun; Wu Zhenjun

    2009-01-01

    The effect of zinc immersion and the role of fluoride in nickel plating bath were mainly investigated in nickel electroplating on magnesium alloy AZ91D. The state of zinc immersion, the composition of zinc film and the role of fluoride in nickel plating bath were explored from the curves of open circuit potential (OCP) and potentiodynamic polarization, the images of scanning electron microscopy (SEM) and the patterns of energy dispersive X-ray (EDX). Results show that the optimum zinc film mixing small amount of Mg(OH) 2 and MgF 2 is obtained by zinc immersion for 30-90 s. The corrosion potential of magnesium alloy substrate attached zinc film will be increased in nickel plating bath and the quantity of MgF 2 sandwiched between magnesium alloy substrate and nickel coating will be reduced, which contributed to produce nickel coating with good performance. Fluoride in nickel plating bath serves as an activator of nickel anodic dissolution and corrosion inhibitor of magnesium alloy substrate. 1.0-1.5 mol dm -3 of F - is the optimum concentration range for dissolving nickel anode and protecting magnesium alloy substrate from over-corrosion in nickel plating bath. The nickel coating with good adhesion and high corrosion resistance on magnesium alloy AZ91D is obtained by the developed process of nickel electroplating. This nickel layer can be used as the rendering coating for further plating on magnesium alloys.

  14. The effects of maternal magnesium sulfate treatment on newborns: a prospective controlled study.

    Science.gov (United States)

    Riaz, M; Porat, R; Brodsky, N L; Hurt, H

    1998-01-01

    To evaluate the effects of maternal magnesium sulfate treatment on newborn outcome. Subjects were newborn infants delivered at > or = 34 weeks of gestation whose mothers received a minimum of 12 hours of intravenous MgSO4 therapy before delivery. Control infants were the next born infants of similar gestational age. Outcome recorded at delivery included Apgar scores, whether resuscitation was required, and whether respiratory depression or decreased tone were noted by the physician in attendance. Pneumocardiograms on magnesium-exposed and control infants, obtained within 6 to 18 hours after delivery, were analyzed postdischarge by a single investigator who was blinded to group. The nursery course, feeding patterns, time to first stool, and time to first void were recorded. All patient care decisions, including admission to the neonatal intensive care unit (NICU) or term nursery, were independent of study protocol. A total of 26 magnesium-exposed and 26 control infants were enrolled. The mean total dose of MgSO4 before delivery was 51.2+/-24 gm; the mean duration of therapy was 23.1+/-10 hours. The mean maternal serum magnesium level before delivery was 5.8+/-1.1 mg/dl. The infants' mean cord or initial serum magnesium level was 5.2+/-1.0 mg/dl, which correlated with the maternal magnesium level before delivery (r=0.81, p or = 0.16). There were no significant differences in number of episodes of feeding intolerance or in time to first stool or void between MgSO4-exposed and control infants (all p > or = 0.31). Infants born to mothers treated with MgSO4 were more likely to be hypotonic and have lower Apgar scores at birth. Beyond the immediate postdelivery period, there were no additional complications in this cohort attributable to prenatal MgSO4 exposure. We suggest that pediatricians attend deliveries of magnesium-exposed infants.

  15. Common variants in CLDN14 are associated with differential excretion of magnesium over calcium in urine.

    Science.gov (United States)

    Corre, Tanguy; Olinger, Eric; Harris, Sarah E; Traglia, Michela; Ulivi, Sheila; Lenarduzzi, Stefania; Belge, Hendrica; Youhanna, Sonia; Tokonami, Natsuko; Bonny, Olivier; Houillier, Pascal; Polasek, Ozren; Deary, Ian J; Starr, John M; Toniolo, Daniela; Gasparini, Paolo; Vollenweider, Peter; Hayward, Caroline; Bochud, Murielle; Devuyst, Olivier

    2017-01-01

    The nature and importance of genetic factors regulating the differential handling of Ca 2+ and Mg 2+ by the renal tubule in the general population are poorly defined. We conducted a genome-wide meta-analysis of urinary magnesium-to-calcium ratio to identify associated common genetic variants. We included 9320 adults of European descent from four genetic isolates and three urban cohorts. Urinary magnesium and calcium concentrations were measured centrally in spot urine, and each study conducted linear regression analysis of urinary magnesium-to-calcium ratio on ~2.5 million single-nucleotide polymorphisms (SNPs) using an additive model. We investigated, in mouse, the renal expression profile of the top candidate gene and its variation upon changes in dietary magnesium. The genome-wide analysis evidenced a top locus (rs172639, p = 1.7 × 10 -12 ), encompassing CLDN14, the gene coding for claudin-14, that was genome-wide significant when using urinary magnesium-to-calcium ratio, but not either one taken separately. In mouse, claudin-14 is expressed in the distal nephron segments specifically handling magnesium, and its expression is regulated by chronic changes in dietary magnesium content. A genome-wide approach identified common variants in the CLDN14 gene exerting a robust influence on the differential excretion of Mg 2+ over Ca 2+ in urine. These data highlight the power of urinary electrolyte ratios to unravel genetic determinants of renal tubular function. Coupled with mouse experiments, these results support a major role for claudin-14, a gene associated with kidney stones, in the differential paracellular handling of divalent cations by the renal tubule.

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

    Directory of Open Access Journals (Sweden)

    Atabak Najafi

    2012-10-01

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

  17. Magnesium-Dependent Interaction of PKR with Adenovirus VAI

    Energy Technology Data Exchange (ETDEWEB)

    K Launer -Felty; C Wong; A Wahid; G Conn; J Cole

    2011-12-31

    Protein kinase R (PKR) is an interferon-induced kinase that plays a pivotal role in the innate immunity pathway for defense against viral infection. PKR is activated to undergo autophosphorylation upon binding to RNAs that contain duplex regions. Activated PKR phosphorylates the {alpha}-subunit of eukaryotic initiation factor 2, thereby inhibiting protein synthesis in virus-infected cells. Viruses have evolved diverse PKR-inhibitory strategies to evade the antiviral response. Adenovirus encodes virus-associated RNA I (VAI), a highly structured RNA inhibitor that binds PKR but fails to activate. We have characterized the stoichiometry and affinity of PKR binding to define the mechanism of PKR inhibition by VAI. Sedimentation velocity and isothermal titration calorimetry measurements indicate that PKR interactions with VAI are modulated by Mg{sup 2+}. Two PKR monomers bind in the absence of Mg{sup 2+}, but a single monomer binds in the presence of divalent ion. Known RNA activators of PKR are capable of binding multiple PKR monomers to allow the kinase domains to come into close proximity and thus enhance dimerization. We propose that VAI acts as an inhibitor of PKR because it binds and sequesters a single PKR in the presence of divalent cation.

  18. The influence of alpha-zearalenol on magnesium concentration in cellular subfractions of certain tissues of female rats and their progeny.

    Science.gov (United States)

    Pasternak, Kazimierz; Kiełczykowska, Małgorzata; Sztanke, Małgorzata; Borzecki, Andrzej

    2003-06-01

    The purpose of the research work was to study the influence of alpha-zearalenol on magnesium concentration in cellular subfractions of certain tissues of female rats and their progeny. Pregnant female rats received alpha-zearalenol at the doses of: 0.05, 0.5 or 1 mg x kg(-1) b.w. After delivery, brain, liver and kidneys of female rats and their progeny were removed and magnesium concentration was measured in cellular subfractions of these tissues. Alpha-zearalenol reduced Mg-level in all the cellular subfractions of female rat tissues. In progeny tissues, alpha-zearalenol decreased magnesium concentration in nuclear subfraction only. In mitochondrial and cytosol subfractions it increased Mg-concentration. The changes in magnesium concentration were depended on alpha-zearalenol doses and tissue nature. The magnesium concentration decrease was higher in female rats than in progeny tissues.

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

    Directory of Open Access Journals (Sweden)

    Junji Takaya

    2015-12-01

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

  20. Magnesium sulfate in aneurysmal subarachnoid hemorrhage: a randomized controlled trial

    NARCIS (Netherlands)

    van den Bergh, Walter M.; Algra, A.; van Kooten, F.; Dirven, C. M. F.; van Gijn, J.; Vermeulen, M.; Rinkel, G. J. E.

    2005-01-01

    BACKGROUND AND PURPOSE: Magnesium reverses cerebral vasospasm and reduces infarct volume after experimental subarachnoid hemorrhage (SAH) in rats. We aimed to assess whether magnesium reduces the frequency of delayed cerebral ischemia (DCI) in patients with aneurysmal SAH. METHODS: Patients were

  1. Magnesium for treating sickle cell disease.

    Science.gov (United States)

    Than, Nan Nitra; Soe, Htoo Htoo Kyaw; Palaniappan, Senthil K; Abas, Adinegara Bl; De Franceschi, Lucia

    2017-04-14

    Sickle cell disease is an autosomal recessive inherited haemoglobinopathy which causes painful vaso-occlusive crises due to sickle red blood cell dehydration. Vaso-occlusive crises are common painful events responsible for a variety of clinical complications; overall mortality is increased and life expectancy decreased compared to the general population. Experimental studies suggest that intravenous magnesium has proven to be well-tolerated in individuals hospitalised for the immediate relief of acute (sudden onset) painful crisis and has the potential to decrease the length of hospital stay. Some in vitro studies and open studies of long-term oral magnesium showed promising effect on pain relief but failed to show its efficacy. The studies show that oral magnesium therapy may prevent sickle red blood cell dehydration and prevent recurrent painful episodes. There is a need to access evidence for the impact of oral and intravenous magnesium effect on frequency of pain, length of hospital stay and quality of life. To evaluate the effects of short-term intravenous magnesium on the length of hospital stay and quality of life in children and adults with sickle cell disease. To determine the effects of long-term oral magnesium therapy on the frequency of painful crises and the quality of life in children and adults with sickle cell disease. We searched the Cochrane Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books.Date of last search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register: 01 December 2016.Date of last search of other resources (clinical trials registries): 29 March 2017. We searched for published and unpublished randomized controlled studies of oral or intravenous magnesium compared to placebo or no magnesium. Authors independently assessed the study quality and extracted the data using standard Cochrane methodologies. We

  2. Corrosion of experimental magnesium alloys in blood and PBS: A gravimetric and microscopic evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Schille, Ch., E-mail: Christine.Schille@med.uni-tuebingen.de [University Hospital Tuebingen, Center for Dentistry, Oral Medicine and Maxillofacial Surgery, Section Medical Materials and Technology, Osianderstr. 2-8, D-72076 Tuebingen (Germany); Braun, M.; Wendel, H.P. [University Hospital Tuebingen, Div. Congenital and Paediatric Cardiac Surgery, University Children' s Hospital, Tuebingen, Germany, Calwerstr. 7/1, D-72076 Tuebingen (Germany); Scheideler, L. [University Hospital Tuebingen, Center for Dentistry, Oral Medicine and Maxillofacial Surgery, Section Medical Materials and Technology, Osianderstr. 2-8, D-72076 Tuebingen (Germany); Hort, N. [GKSS Research Centre, Institute of Materials Research, Max-Planck-Str. 1, D-21502 Geesthacht (Germany); Reichel, H.-P. [Weissensee Company, Buergermeister-Ebert-Str. 30-32, D-36124 Eichenzell (Germany); Schweizer, E.; Geis-Gerstorfer, J. [University Hospital Tuebingen, Center for Dentistry, Oral Medicine and Maxillofacial Surgery, Section Medical Materials and Technology, Osianderstr. 2-8, D-72076 Tuebingen (Germany)

    2011-12-15

    loss was observed. When alloys are ranked according to corrosion susceptibility, the results differ also between the test systems. The MgAl9 alloy, showing the most pronounced corrosion in PBS, was one of the least corroding alloys under simulated in vivo conditions in blood. Thus, the ranking concerning clinical suitability of the magnesium alloys tested in this study is different, depending on the used electrolyte and the kind of method. For a possible clinical use, the alloy MgAl9Zn1 might be preferable for further investigations.

  3. Corrosion of experimental magnesium alloys in blood and PBS: A gravimetric and microscopic evaluation

    International Nuclear Information System (INIS)

    Schille, Ch.; Braun, M.; Wendel, H.P.; Scheideler, L.; Hort, N.; Reichel, H.-P.; Schweizer, E.; Geis-Gerstorfer, J.

    2011-01-01

    MgAl9 alloy, showing the most pronounced corrosion in PBS, was one of the least corroding alloys under simulated in vivo conditions in blood. Thus, the ranking concerning clinical suitability of the magnesium alloys tested in this study is different, depending on the used electrolyte and the kind of method. For a possible clinical use, the alloy MgAl9Zn1 might be preferable for further investigations.

  4. Toxicity of magnesium alloy biodegradation products in experiment

    Directory of Open Access Journals (Sweden)

    Yu. M. Neryanov

    2013-08-01

    Full Text Available The article presents information on the study of possible toxic effects of biodegradation products of original magnesium-based alloy on laboratory rats. The used laboratory methods of investigation are described. Author has examined biochemical parameters of plasma on the base of which endogenous intoxication in rats was studied. It was found out that products of alloy biological resorption don’t cause toxic effects on tissues and don’t enhance cell destruction, that is evidenced by the absence of signs of endogenous intoxication and oxidative damage of functional macromolecules. Materials and methods. We used white mongrel male rats weighing 220-270 g (n = 20. Fixator consisting of a modified magnesium alloy ML-10 was implanted into the femur muscle mass of the animals of the experimental group (n = 14. The control group consisted of white mongrel male rats weighing 230-250 g (n = 6, which were not subjected to surgery (intact group. The degree of oxidative damage to proteins, the content of the average molecular weight, nucleic acids and the stable metabolites of nitric oxide were evaluated in plasma. Results and discussion. The studies revealed the reliable (relative to the intact group increase in the content of all fractions of middle molecules in the plasma of the experimental group of rats, the increase shows only that the immune system of animals with magnesium implants is in a reactive state and responds with minor release of biologically active substances into the bloodstream. At this rate of endogenous intoxication this exponent usually increases tenfold, but we have not seen that. Levels of stable metabolites of nitric oxide increase insignificantly(1,4 times, that likely indicates more on the start of adaptive signaling processes than a pathological condition. The experimental data concerning the content of nucleic acids in the plasma of animals with magnesium implants testifies in support of this hypothesis. There were no

  5. Do we need to measure vitamin B12 and magnesium in morbidly obese patients with type 2 diabetes mellitus?

    Directory of Open Access Journals (Sweden)

    Wåhlén A

    2017-05-01

    Full Text Available Anna Wåhlén,1 Arvo Haenni,2,3 Hans-Erik Johansson1–3 1Östervåla Primary Health Care Centre, Östervåla, 2Department of Public Health and Caring Sciences/Geriatrics, Uppsala University, Uppsala, 3Skönvikt, Outpatient Clinic of Obesity Care, Säter, Sweden Objective: We aimed to investigate the prevalence of B12 deficiency in metformin-treated, morbidly obese, type 2 diabetes mellitus (T2DM patients, compared to morbidly obese controls, as well as to evaluate the magnesium status. Design: Retrospective cross-sectional analysis of plasma vitamin B12, plasma magnesium, glucometabolic status and clinical measurements in all consecutive morbidly obese patients was conducted during 1 year. Setting: Outpatient Clinic of Obesity Care. Subjects: One hundred forty-seven patients were evaluated: 107 morbidly obese controls and 40 metformin-treated, morbidly obese patients with T2DM. Main outcome measures: Circulating plasma concentrations of vitamin B12 (cobalamin, magnesium, clinical measurements and metformin medication. Results: There were differences between the two groups regarding age, sagittal diameter, glucose parameters and magnesium concentrations. Longer diabetes duration was associated with lower magnesium. Metformin-treated T2DM patients had lower magnesium (0.76±0.07 mmol/L than controls (0.82±0.07 mmol/L. A subgroup analysis of 26 non-metformin-treated T2DM patients showed a normal magnesium concentration compared to controls, that is, 0.81±0.06 mmol/L. We found no statistical difference in B12 concentrations between the two groups. Conclusion: To fully benefit from metformin medication, routine testing of B12 as well as magnesium in metformin-treated, morbidly obese patients should be performed, with consideration of substitution to avoid low levels. Keywords: metformin medication, vitamin B12, magnesium, type 2 diabetes mellitus, morbidly obese

  6. Magnesium sacrificial anode behavior at elevated temperature

    International Nuclear Information System (INIS)

    Othman, Mohsen Othman

    2006-01-01

    Magnesium sacrificial anode coupled to mild steel was tasted in sodium chloride and tap water environments at elevated temperatures. The anode failed to protect the mild steel specimens in tap water environment at all temperatures specified. This was partly due to low conductivity of this medium. The temperature factor did not help to activate the anode in this medium. In sodium chloride environment the anode demonstrated good protection for steel cathodes. The weight loss was high for magnesium in sodium chloride environment particularly beyond 60 degree centigrade. In tap water environment the weight loss was negligible for the anode. It also suffered localized shallow pitting corrosion. Magnesium anode cannot be utilized where high temperature is involved particularly in high conductivity mediums. Protection of structures containing high resistivity waters is not feasible using sacrificial anode system. (author)

  7. [Neuroprotection for preterm infants with antenatal magnesium sulphate].

    Science.gov (United States)

    Marret, S; Ancel, P-Y

    2016-12-01

    To evaluate in preterm born children the neuroprotective benefits and the risks, at short- and long-term outcome, of the antenatal administration of magnesium sulphate (MgSO 4 ) in women at imminent risk of preterm delivery. Computer databases Medline, the Cochrane Library and the recommendations of various international scientific societies. Given the demonstrated benefit of antenatal MgSO 4 intravenous administration on the reduction of cerebral palsy rates and the improvement of motor development in children born preterm, it is recommended for all women whose imminent delivery is expected or programmed before 32 weeks of gestation (WG) (grade A). The analysis of the literature finds no argument for greater benefit of antenatal MgSO 4 administration in sub-groups of gestational age, or depending on the type of pregnancy (single or multiple pregnancy) or with the cause of preterm birth (NP2). Its administration is recommended before 32 WG, if single or multiple pregnancy, whatever the cause of prematurity (grade B). It is recommended 4g loading dose (professional consensus). With a loading dose of 4g intravenous (IV) in 20min, the serum magnesium is lower than with intramuscular suggesting a preference for the IV route (professional consensus). It is proposed to use a maintenance dose of 1g/h until delivery with a maximum recommended duration of 12hours without exceeding a cumulative dose of 50g (professional consensus). These doses are without severe adverse maternal side effects or adverse effects in newborns at short- and medium-term outcome (NP1). It is recommended to administer magnesium sulfate to the women at high risk of imminent preterm birth before 32 WG, whether expected or planned (grade A), with a 4g IV loading dose followed by a maintenance dose of 1g/h for 12hours (professional consensus), the pregnancy is single or multiple, whatever the cause of prematurity (professional consensus). Copyright © 2016. Published by Elsevier Masson SAS.

  8. The potential for ionic liquid electrolytes to stabilise the magnesium interface for magnesium/air batteries

    International Nuclear Information System (INIS)

    Khoo, Timothy; Howlett, Patrick C.; Tsagouria, Maureen; MacFarlane, Douglas R.; Forsyth, Maria

    2011-01-01

    Magnesium/air batteries are a possible high-energy density power source that, to date, have not received strong commercial interest due to issues with the corrosion of the magnesium and evaporation of the electrolyte. In this work we report on the use of ionic liquid based electrolytes to stabilise the metal/electrolyte interface and their impact on the electrochemical performance. Galvanostatic measurements indicate that the water content of the ionic liquid electrolyte plays an important role in the cell discharge characteristics. Surface characterisation using EIS, ATR-FTIR and powder diffraction examined the unique properties of the surface film formed on the magnesium anode.

  9. Multi-regional investigation of the relationship between functional MRI blood oxygenation level dependent (BOLD activation and GABA concentration.

    Directory of Open Access Journals (Sweden)

    Ashley D Harris

    Full Text Available Several recent studies have reported an inter-individual correlation between regional GABA concentration, as measured by MRS, and the amplitude of the functional blood oxygenation level dependent (BOLD response in the same region. In this study, we set out to investigate whether this coupling generalizes across cortex. In 18 healthy participants, we performed edited MRS measurements of GABA and BOLD-fMRI experiments using regionally related activation paradigms. Regions and tasks were the: occipital cortex with a visual grating stimulus; auditory cortex with a white noise stimulus; sensorimotor cortex with a finger-tapping task; frontal eye field with a saccade task; and dorsolateral prefrontal cortex with a working memory task. In contrast to the prior literature, no correlation between GABA concentration and BOLD activation was detected in any region. The origin of this discrepancy is not clear. Subtle differences in study design or insufficient power may cause differing results; these and other potential reasons for the discrepant results are discussed. This negative result, although it should be interpreted with caution, has a larger sample size than prior positive results, and suggests that the relationship between GABA and the BOLD response may be more complex than previously thought.

  10. {open_quotes}Exchange-spring{close_quotes} Nd-Fe-B alloys: Investigations into reversal mechanisms and their temperature dependence

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, L.H.; Welch, D.O. [Brookhaven National Labs., Upton, NY (United States); Panchanathan, V. [Magnequench International, (MQI), Inc., Anderson, IN (United States)

    1996-10-01

    In order to investigate factors affecting coercivity a series of two-phase Nd{sub 2}Fe{sub 14}B-based nanocomposite alloys with different excess iron concentrations were produced by melt-spinning methods. The constituent grain size was estimated by diffraction methods to be in the range of 150 {Angstrom} - 500 {Angstrom}, and room-temperature demagnetization curves verify that the alloys studied exhibit a modest remanence enhancement. Isothermal remanence magnetization (IRM) and dc-demagnetization (DCD) measurements performed at temperatures in the range 275 K {le} T {le} 350 K illustrate that the coercivity and irreversible magnetization develops in a bimodal, incoherent manner from a demagnetized state but upon demagnetization from a saturated state the system evinces collective, exchange-coupled behavior as illustrated by the reversible magnetization M{sub rev}. The temperature dependencies and values of the irreversible susceptibility X{sub irr} (DCD) suggest that a moderating phase with a magnetic anisotropy intermediate to the two constituent main phases may be present in the alloys.

  11. The experiment of magnesium ECAP miniplate as alternative biodegradable material (on male white New Zealand rabbits)

    Science.gov (United States)

    Wiwanto, Siska; Sulistyani, Lilies Dwi; Latief, Fourier Dzar Eljabbar; Supriadi, Sugeng; Priosoeryanto, Bambang Pontjo; Latief, Benny Syariefsyah

    2018-02-01

    Study of biodegradations of Magnesium ECAP (Equal Channel Angular Pressing) miniplate in the osteosynthesis system has been used as a new material for plate and screw in oral and maxillofacial surgery. This miniplate and screw that were made of Magnesium ECAP were implanted in the femurs of New Zealand rabbits. The degradation process was detected through pocket gas that appeared in hard and soft tissues surrounding in the implanted miniplates and screws. From the changes on the tissues, we can assess the biodegradation process by measuring the gas pocket through micro-CT Scan. Upon the first month of study we euthanized the rabbits and made a micro-CT Scan to see how far the effect of the gas pocket was. Histological analyses were performed to investigate the local tissue response adjacent to the Magnesium ECAP miniplates. We analyzed the femur of a rabbit a month, three months, and five months after implantation. The result showed a degradation rate in the implanted Magnesium ECAP miniplate of 0.61±0.39 mm/year. Unlike the screws, miniplates have higher water content and blood flow than bone, therefore they degrade faster. This study shows promising results for further development of Magnesium ECAP and in the production of osteosynthesis material for rigid fixation in Oral and Maxillofacial skeleton.

  12. In vivo testing of a bioabsorbable magnesium alloy serving as total ossicular replacement prostheses.

    Science.gov (United States)

    Lensing, Rebecca; Behrens, Peter; Müller, Peter Paul; Lenarz, Thomas; Stieve, Martin

    2014-01-01

    Magnesium alloys have been investigated in different fields of medicine and represent a promising biomaterial for implants due to characteristics like bioabsorbability and osteoinduction. The objective of this study was to evaluate the usability of magnesium as implant material in middle ear surgery. Magnesium implants were placed into the right middle ear of eighteen New Zealand White rabbits. Nine animals were euthanized after four weeks and nine animals after three month. The petrous bones were removed and embedded in epoxy resin. The specimens were then polished, stained and evaluated with the aid of a light microscope. The histological examination revealed a good biocompatibility. After four weeks, a beginning corrosion of the implant's surface and low amount of trabecular bone formation in the area of the stapes base plate was observed. A considerable degradation of implants and obvious bone formation was found three month after implantation. The magnesium alloy used in the present study partly corroded too fast, so that a complete bone reconstruction could not be established in time. The increased osteoinduction on the stapes base plate resulted in a tight bone-implant bonding. Thus, a promising application of magnesium could be a coating of biomaterials in order to improve the bony integration of implants.

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

    International Nuclear Information System (INIS)

    Lee, Seung-Tae

    2009-01-01

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

  14. Enhanced antimicrobial properties, cytocompatibility, and corrosion resistance of plasma-modified biodegradable magnesium alloys.

    Science.gov (United States)

    Zhao, Ying; Jamesh, Mohammed Ibrahim; Li, Wing Kan; Wu, Guosong; Wang, Chenxi; Zheng, Yufeng; Yeung, Kelvin W K; Chu, Paul K

    2014-01-01

    Magnesium alloys are potential biodegradable materials and have received increasing attention due to their outstanding biological performance and mechanical properties. However, rapid degradation in the physiological environment and potential toxicity limit clinical applications. Recently, special magnesium-calcium (Mg-Ca) and magnesium-strontium (Mg-Sr) alloys with biocompatible chemical compositions have been reported, but the rapid degradation still does not meet clinical requirements. In order to improve the corrosion resistance, a rough, hydrophobic and ZrO(2)-containing surface film is fabricated on Mg-Ca and Mg-Sr alloys by dual zirconium and oxygen ion implantation. Weight loss measurements and electrochemical corrosion tests show that the corrosion rate of the Mg-Ca and Mg-Sr alloys is reduced appreciably after surface treatment. A systematic investigation of the in vitro cellular response and antibacterial capability of the modified binary magnesium alloys is performed. The amounts of adherent bacteria on the Zr-O-implanted and Zr-implanted samples diminish remarkably compared to the unimplanted control. In addition, significantly enhanced cell adhesion and proliferation are observed from the Zr-O-implanted sample. The results suggest that dual zirconium and oxygen ion implantation, which effectively enhances the corrosion resistance, in vitro biocompatibility and antimicrobial properties of Mg-Ca and Mg-Sr alloys, provides a simple and practical means to expedite clinical acceptance of biodegradable magnesium alloys. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

  16. Magnesium–Gold Alloy Formation by Underpotential Deposition of Magnesium onto Gold from Nitrate Melts

    Directory of Open Access Journals (Sweden)

    Vesna S. Cvetković

    2017-03-01

    Full Text Available Magnesium underpotential deposition on gold electrodes from magnesium nitrate –ammonium nitrate melts has been investigated. Linear sweep voltammetry and potential step were used as electrochemical techniques. Scanning electron microscopy (SEM, energy dispersive spectrometry (EDS and X-ray diffraction (XRD were used for characterization of obtained electrode surfaces. It was observed that reduction processes of nitrate, nitrite and traces of water (when present, in the Mg underpotential range studied, proceeded simultaneously with magnesium underpotential deposition. There was no clear evidence of Mg/Au alloy formation induced by Mg UPD from the melt made from eutectic mixture [Mg(NO32·6H2O + NH4NO3·XH2O]. However, EDS and XRD analysis showed magnesium present in the gold substrate and four different Mg/Au alloys being formed as a result of magnesium underpotential deposition and interdiffusion between Mg deposit and Au substrate from the melt made of a nonaqueous [Mg(NO32 + NH4NO3] eutectic mixture at 460 K.

  17. The triple synergy of ethylmethylhydroxypyridine succinate, magnesium, and vitamin B6: Molecular mechanisms

    Directory of Open Access Journals (Sweden)

    O. A. Gromova

    2017-01-01

    Full Text Available Objective: to evaluate the triple effect of ethylmethylhydroxypyridine succinate (EMHPS, organic magnesium salt (magnesium lactate, and vitamin B6 (pyridoxine.Material and methods. A systematic analysis of the molecular mechanisms of the triple synergic action of EMHPS, magnesium, and vitamin B6 was carried out. For chemoinformational analysis, the investigators developed a new mathematical method based on the combinatorial theory of solvability, which allows one to obtain quantitative estimates of the affinity constants of proteome proteins.Results. The pharmacological effects of the EMHPS molecule characterized by nootropic and antioxidant properties are shown to work in synergy with magnesium and vitamin B6. A systematic analysis of synergy interactions indicated 46 biological roles, in which the synergy of EMHPS, magnesium, and pyridoxine could be manifested. The main goals of this synergy are to protect neurons from damage, by combating excitotoxicity in the cells and to neutralize excess homocysteine (to reduce the risk of ischemic and thrombotic stroke, myocardial infarction, and coronary heart disease; to improve cognitive functions and neuromuscular transmission, to reduce anxiety, by activating acetylcholine, GABA, and dopamine receptors; to normalize lipid and glucose metabolism, by lowering hyperglycemia and improving the processing of fats.

  18. Antepartum/postpartum depressive symptoms and serum zinc and magnesium levels.

    Science.gov (United States)

    Wójcik, Jacek; Dudek, Dominika; Schlegel-Zawadzka, Małgorzata; Grabowska, Mariola; Marcinek, Antoni; Florek, Ewa; Piekoszewski, Wojciech; Nowak, Rafał J; Opoka, Włodzimierz; Nowak, Gabriel

    2006-01-01

    In the present study, we investigated the relationship between depressive symptoms and serum zinc and magnesium level in antepartum and postpartum women. All women received standard vitamin, zinc and magnesium supplementation. Sixty-six pregnant women in the Czerwiakowski Hospital in Kraków were assessed for prepartum depressive symptoms using the Beck Depression Inventory (BDI). Sixty-two and fifty-eight women were also assessed for postpartum depressive symptoms (using Edinburgh Postnatal Depression Rating Scale, EPDRS) at 3 and 30 days after delivery, respectively. Serum zinc and magnesium levels were also determined at these time points, however, the number of examined subjects were diminished. A significantly higher EPDRS score (by 45%), indicating severity of depressive symptoms, was found on the 3rd day after childbirth compared with the 30th postpartum day. Moreover, the early post-delivery period (3rd day) was characterized by a 24% lower serum zinc concentration than that found on the 30th day after childbirth. BDI scores assessed a month before childbirth revealed mild depressive symptoms, which was accompanied by a serum zinc concentration similar to that found on the 3rd day after delivery. No significant alterations were found in the magnesium levels between these time points. The present results demonstrated a relationship between severity of depressive symptoms and decreased serum zinc (but not magnesium) concentration in a very specific type of affective disorder, the postpartum depression.

  19. Biocompatibility enhancement of rare earth magnesium alloy by laser surface processing

    Science.gov (United States)

    Nie, Shilin; Wang, Yuqing; Liu, Haifeng; Guan, Yingchun

    2018-01-01

    Although magnesium and magnesium alloys are considered biocompatible and biodegradable, insufficient biocompatibility in body fluid environment is still the major drawback of magnesium alloys for their successful applications as biodegradable orthopaedic implants. In this work, magnesium alloy surface with both enhanced corrosion resistance and better cell adhesion property was directly fabricated by laser surface processing. Laser surface melting was used to improve corrosion resistance of Mg-6Gd-0.6Ca alloy. After laser surface melting, laser surface texturing was utilized on melted surface for better cell adhesion property. The corrosion resistance of laser-treated and as-received samples were evaluated using electrochemical technique. The effect of laser surface treatment on phase and microstructure evolution was evaluated using scanning electron microscopy, optical microscopy and X-ray diffraction. This work investigated the effect of laser treatment on cell distribution across the surface of magnesium alloy substrates. Osteoblast was cultured on the laser-treated surface and as-received surface. Cell morphology was observed with a scanning electron microscopy, and cell viability was evaluated by optical density measurement.

  20. Corrosion of magnesium and magnesium–calcium alloy in biologically-simulated environment

    Directory of Open Access Journals (Sweden)

    Richard Harrison

    2014-10-01

    Full Text Available A study of biocompatibility and corrosion of both metallic magnesium (Mg and a magnesium alloy containing 1% calcium (Mg–Ca were investigated in in vitro culture conditions with and without the presence of bone marrow derived human mesenchymal stem cells (hMSCs. Chemical analysis of the degraded samples was performed using XRD and FEGSEM. The results from the XRD analysis strongly suggested that crystalline phase of magnesium carbonate was present on the surface of both the Mg and Mg–Ca samples. Flame absorption spectrometry was used to analyse the release of magnesium and calcium ions into the cell culture medium. Magnesium concentration was kept consistently at a level ranging from 40 to 80 mM for both Mg and Mg–Ca samples. No cell growth was observed when in direct contact with the metals apart from a few cells observed at the bottom of culture plate containing Mg–Ca alloy. In general, in vitro study of corrosion of Mg–Ca in a biologically-simulated environment using cell culture medium with the presence of hMSCs demonstrated close resemblances to in vivo corrosion. Although in vitro corrosion of Mg–Ca revealed slow corrosion rate and no immediate cytotoxicity effects to hMSCs, its corrosion rate was still too high to achieve normal stem cell growth when cells and alloys were cultured in vitro in direct contact.

  1. Carbon coated magnesium oxide based amperometric glucose biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Silva, L.L.; Mello, J.M.M.; Fiori, M.A.; Duarte, G.W. [Universidade Comunitaria Regional de Chapeco (UNICHAPECO), SC (Brazil); Fernandes, S.C. [Instituto Federal Catarinense (IFC), Blumenau, SC (Brazil); Riella, H.G. [Centro Universitario Barriga Verde (UNIBAVE), Orleans, SC (Brazil); Anzolin, C.; Figueiro, A.; Grando, M.C. [Universidade Federal de Santa Catarina (UFSC), SC (Brazil)

    2016-07-01

    Full text: Diabetes is a serious disease that is harmful to human health since it is related to cardiovascular and stroke events. Since the first glucose oxidase (GOx) sensor, different approaches have been explored. Carbon was used to cover nano-magnesium oxide (MgO-C) forming a core-shell which was used to improve its biocompatibility and chemical stability for the preparation of GOx biosensor. MgO nanostructures have been prepared by calcination of the gel formed by the reaction of magnesium acetate tetrahydrate dissolved in cetyltrimethylammonium with the addition of tartaric acid solution. MgO-C nanostructures were obtained by heating MgO nanoparticles previously prepared together with glucose and PEG dissolved in an aqueous suspension. Reaction conditions such as concentration of magnesium precursor, temperature and aging time show important roles in the size, morphology and growth process of the final products. The core-shell structure was evidenced by SEM/FEG and XRD and showed that the product appeared to have morphological forms of nanowires. GOx was spread onto the surface of a modified carbon paste electrode (CPE) doped with MgO-C and the effect on the biosensing properties investigated by comparing the electrochemical properties of the proposed biosensor with bare and modified CPEs by cyclic voltammetry. The amount of modifier in CPE (5-75 weight% with respect to graphite) influences the peak current and the influence of different experimental parameters (enzyme percentage, pH solution and amperometric methods) was also investigated. The results demonstrate that the GOx retains its biocatalytic activity and that the bioelectrode modified can be a possible use for other nanotechnological purposes including biomedical ones. (author)

  2. Solidification, growth mechanisms, and associated properties of Al-Si and magnesium lightweight casting alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hosch, Timothy [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Continually rising energy prices have inspired increased interest in weight reduction in the automotive and aerospace industries, opening the door for the widespread use and development of lightweight structural materials. Chief among these materials are cast Al-Si and magnesium-based alloys. Utilization of Al-Si alloys depends on obtaining a modified fibrous microstructure in lieu of the intrinsic flake structure, a process which is incompletely understood. The local solidification conditions, mechanisms, and tensile properties associated with the flake to fiber growth mode transition in Al-Si eutectic alloys are investigated here using bridgman type gradient-zone directional solidification. Resulting microstructures are examined through quantitative image analysis of two-dimensional sections and observation of deep-etched sections showing three-dimensional microstructural features. The transition was found to occur in two stages: an initial stage dominated by in-plane plate breakup and rod formation within the plane of the plate, and a second stage where the onset of out-of-plane silicon rod growth leads to the formation of an irregular fibrous structure. Several microstructural parameters were investigated in an attempt to quantify this transition, and it was found that the particle aspect ratio is effective in objectively identifying the onset and completion velocity of the flake to fiber transition. The appearance of intricate out-of-plane silicon instability formations was investigated by adapting a perturbed-interface stability analysis to the Al-Si system. Measurements of silicon equilibrium shape particles provided an estimate of the anisotropy of the solid Si/liquid Al-Si system and incorporation of this silicon anisotropy into the model was found to improve prediction of the instability length scale. Magnesium alloys share many of the benefits of Al-Si alloys, with the added benefit of a 1/3 lower density and increased machinability. Magnesium castings

  3. 40 CFR 721.9513 - Modified magnesium silicate polymer (generic).

    Science.gov (United States)

    2010-07-01

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

  4. Serum Magnesium Levels in Non-Pregnant, Pregnant And Pre ...

    African Journals Online (AJOL)

    The objective of this study was to compare the serum magnesium levels in normal pregnancy and pregnancy complicated by pre-eclampsia since magnesium has been implicated in the pathogenesis of vascular dysfunction. We measured serum magnesium levels in patients with pre-eclampsia (n=36), patients with normal ...

  5. Is serum magnesium estimate necessary in patients with Eclampsia ...

    African Journals Online (AJOL)

    The therapeutic index of magnesium is said to be low, hence, there are fears of toxicity when used as anticonvulsant in eclamptic patients. The objective of this study was to determine the serum levels of magnesium in eclamptic patients treated with magnesium sulphate and relate the levels with clinical indicators. It was a ...

  6. Fatigue Analysis of Magnesium Alloys Components for Car Industry

    Science.gov (United States)

    Marsavina, Liviu; Rusu, Lucian; Șerban, Dan Andrei; Negru, Radu Marcel; Cernescu, Anghel

    2017-12-01

    The use of magnesium alloys in the automotive industry increased in the last decade because of their low weight and relative good mechanical properties. However, the variable loading conditions require a good fatigue behavior. This paper summaries the fatigue properties of magnesium alloys and presents new fatigue curve results for die cast AM50 magnesium alloy.

  7. 75 FR 48360 - Magnesium From China and Russia

    Science.gov (United States)

    2010-08-10

    ... COMMISSION Magnesium From China and Russia AGENCY: United States International Trade Commission. ACTION: Scheduling of full five-year reviews concerning the antidumping duty orders on alloy magnesium from China and pure and alloy magnesium from Russia. SUMMARY: The Commission hereby gives notice of the scheduling of...

  8. 75 FR 35086 - Magnesium From China and Russia

    Science.gov (United States)

    2010-06-21

    ... COMMISSION Magnesium From China and Russia AGENCY: United States International Trade Commission. ACTION... orders on magnesium from China and Russia. SUMMARY: The Commission hereby gives notice that it will...)) to determine whether revocation of the antidumping duty orders on magnesium from China and Russia...

  9. Characterization of Damage in Magnesium Using Digital Image Correlation and Electron Backscattered Diffraction Patterning

    Science.gov (United States)

    Nemcko, Michael J.; Mas, Pauline; Bruhis, Moisei; Wilkinson, David S.

    The microscopic strain distribution of commercially pure magnesium has been investigated during room temperature deformation. Digital image correlation (DIC) coupled with electron backscattered diffraction (EBSD) patterning has been used to relate strain measurements with the microstructure. Sheet magnesium tensile samples were etched and a random pattern of points were machined onto the sample surface using a focused ion beam (FIB). The samples were pulled in tension under an optical microscope. Images were obtained in increments and the DIC method was used to calculate the strain distribution. The strain distribution was compared to the EBSD pattern and the results show that strain localization is associated with twin and grain boundaries.

  10. Potency of high-intensity ultrasonic treatment for grain refinement of magnesium alloys

    International Nuclear Information System (INIS)

    Ramirez, A.; Qian Ma; Davis, B.; Wilks, T.; StJohn, D.H.

    2008-01-01

    High-intensity ultrasonic treatment (UT) for grain refinement of magnesium alloys has been investigated using a novel theoretical approach in order to better understand its grain-refining potential and the mechanism of nucleation. The process demonstrated significantly superior grain-refining potency to carbon inoculation for Al-containing magnesium alloys but inferior potency to zirconium for Al-free alloys. Details revealed by applying the theoretical approach to ultrasonic grain refinement provide new clues to understanding the mechanism of grain nucleation by UT

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

    Directory of Open Access Journals (Sweden)

    Xu Wenchen

    2015-01-01

    Full Text Available The isothermal forging process is an effective method to manufacture complex-shaped components of hard-to-work materials, such as magnesium alloys. This study investigates the isothermal forging process of an MB26 magnesium alloy adaptor with three branches. The results show that two-step forging process is appropriate to form the adaptor forging, which not only improves the filling quality but also reduces the forging load compared with one-step forging process. Moreover, the flow line is distributed along the contour of the complex-shaped adaptor forging.

  12. Corrosion resistance of a composite polymeric coating applied on biodegradable AZ31 magnesium alloy.

    Science.gov (United States)

    Zomorodian, A; Garcia, M P; Moura e Silva, T; Fernandes, J C S; Fernandes, M H; Montemor, M F

    2013-11-01

    The high corrosion rate of magnesium alloys is the main drawback to their widespread use, especially in biomedical applications. There is a need for developing new coatings that provide simultaneously corrosion resistance and enhanced biocompatibility. In this work, a composite coating containing polyether imide, with several diethylene triamine and hydroxyapatite contents, was applied on AZ31 magnesium alloys pre-treated with hydrofluoric acid by dip coating. The coated samples were immersed in Hank's solution and the coating performance was studied by electrochemical impedance spectroscopy and scanning electron microscopy. In addition, the behavior of MG63 osteoblastic cells on coated samples was investigated. The results confirmed that the new coatings not only slow down the corrosion rate of AZ31 magnesium alloys in Hank's solution, but also enhance the adhesion and proliferation of MG63 osteoblastic cells, especially when hydroxyapatite nanoparticles were introduced in the coating formulation. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Thimmasandra Narayan Ramesh

    2015-01-01

    Full Text Available Magnesium hydroxide is used as an adsorbent for the removal of indigo carmine dye from aqueous solution. We have investigated the effectiveness of removal of indigo carmine dye from aqueous solutions at pH 6-7 and 12-13 using magnesium hydroxide thereby varying the dose of the adsorbent, concentration of the dye, duration, and temperature. Structural transformations of adsorbent during the adsorption process at different pH values are monitored using powder X-ray diffraction and infrared spectroscopy. Different types of adsorption isotherm models were evaluated and it was found that Langmuir isotherm fits well at both pH values (6-7 and 12-13. Adsorption of indigo carmine onto magnesium hydroxide at pH 6-7/pH 12-13 follows pseudo-second order rate kinetics.

  14. Analyzing the effect of high repetition laser shock peening on dynamic corrosion rate of magnesium

    Science.gov (United States)

    Caralapatti, Vinodh Krishna; Narayanswamy, Sivakumar

    2017-08-01

    Magnesium as implant material is being investigated extensively due to its superior suitability. With corrosion rate being the major obstacle, this paper aims to determine the effects of high repetition laser shock peening (HRLSP) on the dynamic corrosion rate of magnesium. While there is lot of research on corrosion of magnesium, in this work, a specially designed test bench was used for characterization of dynamic corrosion to mimic the physiological conditions experienced by the implant inside human body. From the results, it can be inferred that corrosion rate of peened samples reduced by at least 6 times compared to unpeened sample and sample peened with 66% overlap 1 scans exhibited the least corrosion. The wettability of the samples was also determined as a measure to analyze the effects of HRLSP on biocompatibility. In addition, peening is seen to induce surface corrosion, which minimizes the risks of implant failure.

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

    Directory of Open Access Journals (Sweden)

    Li-Zhai Pei

    2010-09-01

    Full Text Available Magnesium oxide and magnesium aluminate (MgAl2O4 spinel (MAS powders have been synthesized by a simple aqueous sol-gel process using citrate polymeric precursors derived from magnesium chloride, aluminium nitrate and citrate. The thermal decomposition of the precursors and subsequent formation of cubic MgO and MAS were investigated by X-ray diffraction (XRD, scanning electron microscopy (SEM, thermogravimetry-differential scanning calorimetry (TG-DSC and Fourier transform infrared spectra (FTIR. The single phase cubic MgO powder and MAS powder form after heat treatment at 800 and 1200 °C, respectively. The particle size of the MgO and MAS powders is about 100 nm and several micrometers, respectively. Ball milling eliminates the size of MgO and MgAl2O4 spinel powders by decreasing the conglomeration of the powders.

  16. Hydrothermal synthesis of hexagonal magnesium hydroxide nanoflakes

    International Nuclear Information System (INIS)

    Wang, Qiang; Li, Chunhong; Guo, Ming; Sun, Lingna; Hu, Changwen

    2014-01-01

    Graphical abstract: Hexagonal Mg(OH) 2 nanoflakes were synthesized via hydrothermal method in the presence of PEG-20,000. Results show that PEG-20,000 plays an important role in the formation of this kind of nanostructure. The SAED patterns taken from the different positions on a single hexagonal Mg(OH) 2 nanoflake yielded different crystalline structures. The structure of the nanoflakes are polycrystalline and the probable formation mechanism of Mg(OH) 2 nanoflakes is discussed. - Highlights: • Hexagonal Mg(OH) 2 nanoflakes were synthesized via hydrothermal method. • PEG-20,000 plays an important role in the formation of hexagonal nanostructure. • Mg(OH) 2 nanoflakes show different crystalline structures at different positions. • The probable formation mechanism of hexagonal Mg(OH) 2 nanoflakes was reported. - Abstract: Hexagonal magnesium hydroxide (Mg(OH) 2 ) nanoflakes were successfully synthesized via hydrothermal method in the presence of the surfactant polyethylene glycol 20,000 (PEG-20,000). Results show that PEG-20,000 plays an important role in the formation of this kind of nanostructure. The composition, morphologies and structure of the Mg(OH) 2 nanoflakes were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The SAED patterns taken from the different positions on a single hexagonal Mg(OH) 2 nanoflake show different crystalline structures. The structure of the nanoflakes are polycrystalline and the probable formation mechanism of Mg(OH) 2 nanoflakes is discussed. Brunauer–Emmett–Teller (BET) analysis were performed to investigate the porous structure and surface area of the as-obtained nanoflakes

  17. Size Effect on Magnesium Alloy Castings

    Science.gov (United States)

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

    2016-06-01

    The effect of grain size on tensile and fatigue properties has been investigated in cast Mg alloys of Mg-2.98Nd-0.19Zn (1530 μm) and Mg-2.99Nd-0.2Zn-0.51Zr (41 μm). The difference between RB and push-pull fatigue testing was also evaluated in both alloys. The NZ30K05-T6 alloy shows much better tensile strengths (increased by 246 pct in YS and 159 pct in UTS) and fatigue strength (improved by ~80 pct) in comparison with NZ30-T6 alloy. RB fatigue testing results in higher fatigue strength compared with push-pull fatigue testing, mainly due to the stress/strain gradient in the RB specimen cross section. The material with coarse grains could be hardened more in the cyclic loading condition than in the monotonic loading condition, corresponding to the lower σ f and the higher σ f/ σ b or σ f/ σ 0.2 ratio compared to the materials with fine grains. The fatigue crack initiation sites and failure mechanism are mainly determined by the applied stress/strain amplitude. In LCF, fatigue failure mainly originates from the PSBs within the surface or subsurface grains of the samples. In HCF, cyclic deformation and damage irreversibly caused by environment-assisted cyclic slip is the crucial factor to influence the fatigue crack. The Coffin-Manson law and Basquin equation, and the developed MSF models and fatigue strength models can be used to predict fatigue lives and fatigue strengths of cast magnesium alloys.

  18. Operating mechanisms of electrolytes in magnesium ion batteries: chemical equilibrium, magnesium deposition, and electrolyte oxidation.

    Science.gov (United States)

    Kim, Dong Young; Lim, Younhee; Roy, Basab; Ryu, Young-Gyoon; Lee, Seok-Soo

    2014-12-21

    Since the early nineties there have been a number of reports on the experimental development of Mg electrolytes based on organo/amide-magnesium chlorides and their transmetalations. However, there are no theoretical papers describing the underlying operating mechanisms of Mg electrolytes, and there is no clear understanding of these mechanisms. We have therefore attempted to clarify the operating mechanisms of Mg electrolytes by studying the characteristics of Mg complexes, solvation, chemical equilibrium, Mg-deposition processes, electrolyte-oxidation processes, and oxidative degradation mechanism of RMgCl-based electrolytes, using ab initio calculations. The formation and solvation energies of Mg complexes highly depend on the characteristics of R groups. Thus, changes in R groups of RMgCl lead to changes in the equilibrium position and the electrochemical reduction and oxidation pathways and energies. We first provide a methodological scheme for calculating Mg reduction potential values in non-aqueous electrolytes and electrochemical windows. We also describe a strategy for designing Mg electrolytes to maximize the electrochemical windows and oxidative stabilities. These results will be useful not only for designing improved Mg electrolytes, but also for developing new electrolytes in the future.

  19. MgCl 2 : The Key Ingredient to Improve Chloride Containing Electrolytes for Rechargeable Magnesium-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Baofei; Huang, Jinhua; Sa, Niya; Brombosz, Scott M.; Vaughey, John T.; Zhang, Lu; Burrell, Anthony K.; Zhang, Zhengcheng; Liao, Chen

    2016-01-01

    The effect of MgCl2 on a series of chloride containing magnesium electrolytes was investigated. In the presence of extra MgCl2, the electrochemical properties of Grignard reagents (RMgCl, R = Ph, Et, iPr) were significantly improved, and the advance of MgCl2 was further demonstrated in Mg-Mo6S8 rechargeable batteries with improved capacities and much smaller over-potentials. MgCl2 was then further proven to be powerful reagent to improve the performance of well-established strong Lewis acid derived magnesium electrolytes including the “all-phenyl” complex (APC) and alkoxide-based magnesium electrolytes. The results suggest that MgCl2 salt is a very important species to benefit all chloride containing electrolytes for rechargeable magnesium-ion batteries.

  20. Magnesium Affects Poly(3-hydroxybutyrate-co-4-hydroxybutyrate Content and Composition by Affecting Glucose Uptake in Delftia acidovorans

    Directory of Open Access Journals (Sweden)

    Lee, W. H.

    2007-01-01

    Full Text Available Precise control of polyhydroxyalkanoate (PHA composition is necessary in order to synthesize polymers with specific properties. Among the various types of PHA that have been identified, those that contain 4-hydroxybutyrate (4HB monomers are especially useful in the medical and pharmaceutical fields as absorbable biomaterial. In this study, we have investigated the effect of magnesium concentration on the biosynthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate [P(3HB-co-4HB] by Delftia acidovorans DS-17. Our results show that, magnesium affects the copolymer content and composition by affecting glucose uptake from the culture medium. Higher concentrations of magnesium resulted in lower molar fractions of 3HB in the copolymer and reduced uptake of glucose. The results show for the first time that magnesium may be used to achieve fine control of biologically synthesized PHA copolymer composition.

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

    Science.gov (United States)

    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.

  2. Superior light metals by texture engineering: Optimized aluminum and magnesium alloys for automotive applications

    International Nuclear Information System (INIS)

    Hirsch, J.; Al-Samman, T.

    2013-01-01

    Aluminum and magnesium are two highly important lightweight metals used in automotive applications to reduce vehicle weight. Crystallographic texture engineering through a combination of intelligent processing and alloying is a powerful and effective tool to obtain superior aluminum and magnesium alloys with optimized strength and ductility for automotive applications. In the present article the basic mechanisms of texture formation of aluminum and magnesium alloys during wrought processing are described and the major aspects and differences in deformation and recrystallization mechanisms are discussed. In addition to the crystal structure, the resulting properties can vary significantly, depending on the alloy composition and processing conditions, which can cause drastic texture and microstructure changes. The elementary mechanisms of plastic deformation and recrystallization comprising nucleation and growth and their orientation dependence, either within the homogeneously formed microstructure or due to inhomogeneous deformation, are described along with their impact on texture formation, and the resulting forming behavior. The typical face-centered cubic and hexagonal close-packed rolling and recrystallization textures, and related mechanical anisotropy and forming conditions are analyzed and compared for standard aluminum and magnesium alloys. New aspects for their modification and advanced strategies of alloy design and microstructure to improve material properties are derived

  3. Investigation of the time-dependent wear behavior of veneering ceramic in porcelain fused to metal crowns during chewing simulations.

    Science.gov (United States)

    Guo, Jiawen; Tian, Beimin; Wei, Ran; Wang, Weiguo; Zhang, Hongyun; Wu, Xiaohong; He, Lin; Zhang, Shaofeng

    2014-12-01

    The excessive abrasion of occlusal surfaces in ceramic crowns limits the service life of restorations and their clinical results. However, little is known about the time-dependent wear behavior of ceramic restorations during the chewing process. The aim of this in vitro study was to investigate the dynamic evolution of the wear behavior of veneering porcelain in PFM crowns as wear progressed, as tested in a chewing simulator. Twenty anatomical metal-ceramic crowns were prepared using Ceramco III as the veneering porcelain. Stainless steel balls served as antagonists. The specimens were dynamically loaded in a chewing simulator with 350N up to 2.4×10(6) loading cycles, with additional thermal cycling between 5 and 55°C. During the testing, several checkpoints were applied to measure the substance loss of the crowns' occlusal surfaces and to evaluate the microstructure of the worn areas. After 2.4×10(6) cycles, the entire wear process of the veneering porcelain in the PFM crowns revealed three wear stages (running-in, steady and severe wear stages). The occlusal surfaces showed traces of intensive wear on the worn areas during the running-in wear stage, and they exhibited the propagation of cracks in the subsurface during steady wear stage. When the severe wear stage was reached, the cracks penetrated the ceramic layer, causing the separation of porcelain pieces. It also exhibited a good correlation among the microstructure, the wear loss and the wear rate of worn ceramic restorations. The results suggest that under the conditions of simulated masticatory movement, the wear performance of the veneering porcelain in PFM crowns indicates the apparent similarity of the tribological characteristics of the traditional mechanical system. Additionally, the evaluation of the wear behavior of ceramic restorations should be based on these three wear stages. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Investigation of the solvent-dependent photolysis of a nonnucleoside reverse-transcriptase inhibitor, antiviral agent efavirenz.

    Science.gov (United States)

    Jordaan, Maryam A; Shapi, Michael

    2017-12-01

    This study sought to investigate the solvent-dependency on the photolysis of efavirenz to gain insight into the photoprocesses involved. The primary mechanisms were firstly the excited-state intramolecular proton transfer (i.e. phototautomerization), which generated the imidic acid phototautomer observed as [M-H] - quasimolecular ion at m/z 314.0070 in the high-performance liquid chromatography-electrospray ionization-time-of-flight mass spectrometry in the negative mode. Secondly, the photoinduced α-cleavage with the loss of a carbonyl group occurred (i.e. photodecarbonylation) to form the photoproduct at m/z 286.0395. The ultraviolet-visible spectra illustrated a large, hyperchromic, and slight bathochromic effect in both the π→π* and n→π* electronic transitions. The largest bathochromic effect was prevalent in the chloroform solvent, i.e. chloroform (π* = 0.58; β = 0.00; α = 0.44) > methanol (π* = 0.60; β = 0.66; α = 0.98) > acetonitrile (π* = 0.75; β = 0.40; α = 0.19). This is due to the significant interaction of the amino group with the excited carbonyl moiety which is attributed to intramolecular phototautomerization resulting in a larger energy shift of the electronic state. A plausible explanation is due to the hydrogen bond donor ability of the polar methanol and nonpolar chloroform solvents, which stabilized the polarized imidic acid phototautomer by means of hydrogen bonding interactions, as opposed to the aprotic acetonitrile which exhibits no hydrogen bonding interactions. The study would form the basis for further photolytic analyses and syntheses to generate a plethora of novel photoproducts with anti-HIV activity based on the biologically active benzoxazinone framework of efavirenz.

  5. Magnesium status and parenteral magnesium sulphate therapy in acute aluminum phosphide intoxication.

    Science.gov (United States)

    Chugh, S N; Kamar, P; Sharma, A; Chugh, K; Mittal, A; Arora, B

    1994-12-01

    The results of an open randomized study on magnesium status and parenteral magnesium sulphate therapy in acute aluminium phosphide intoxication are presented. The study was conducted on 105 patients divided into two group (I & II). Patients of Group I did not receive parenteral magnesium and acted as blank. Magnesium levels were monitored every 6 h for 24 h. Patients of group II received magnesium sulphate therapy. It was administered as 1.0 g (8.1 mEq or 4.05 mmol) magnesium sulphate dissolved in 100 ml of 5 per cent dextrose intravenously as a bolus dose followed by 1.0 g every hour for three successive hours, then 1.0 g every 6 h as a maintenance dose for the next 24 h as intravenous infusion in 5 per cent dextrose. The total dose of magnesium sulphate infused was 30.0 mmol over a period of 24 h (initial dose), then 16.0 mmol (4.0 g) daily till final outcome or a maximum of five days. All the vital parameters were monitored. All the patients were followed till final outcome. The resuscitation methods used were the same in both groups. At the end of the study, mortality rates were calculated in both groups. Hypomagnesaemia was observed as the constant finding in patients of Group I. It was transient and reversed itself without MgSO4. The mortality rate was 52 per cent. On the other hand, magnesium levels rose immediately after parenteral MgSO4 administration in patients of group II and they remained persistently above normal during the observed period.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Photoluminescence of magnesium-associated color centers in LiF crystals implanted with magnesium ions

    Science.gov (United States)

    Nebogin, S. A.; Ivanov, N. A.; Bryukvina, L. I.; V. Shipitsin, N.; E. Rzhechitskii, A.; Papernyi, V. L.

    2018-05-01

    In the present paper, the effect of magnesium nanoparticles implanted in a LiF crystal on the optical properties of color centers is studied. The transmittance spectra and AFM images demonstrate effective formation of the color centers and magnesium nanoparticles in an implanted layer of ∼ 60-100 nm in thickness. Under thermal annealing, a periodical structure is formed on the surface of the crystal and in the implanted layer due to self-organization of the magnesium nanoparticles. Upon excitation by argon laser with a wavelength of 488 nm at 5 K, in a LiF crystal, implanted with magnesium ions as well as in heavily γ-irradiated LiF: Mg crystals, luminescence of the color centers at λmax = 640 nm with a zero-phonon line at 601.5 nm is observed. The interaction of magnesium nanoparticles and luminescing color centers in a layer implanted with magnesium ions has been revealed. It is shown that the luminescence intensity of the implanted layer at a wavelength of 640 nm is by more than two thousand times higher than that of a heavily γ-irradiated LiF: Mg crystal. The broadening of the zero-phonon line at 601.5 nm in the spectrum of the implanted layer indicates the interaction of the emitting quantum system with local field of the surface plasmons of magnesium nanoparticles. The focus of this work is to further optimize the processing parameters in a way to result in luminescence great enhancement of color centers by magnesium nanoparticles in LiF.

  7. Effect of magnesium aluminum silicate glass on the thermal shock resistance of BN matrix composite ceramics

    NARCIS (Netherlands)

    Cai, Delong; Jia, Dechang; Yang, Zhihua; Zhu, Qishuai; Ocelik, Vaclav; Vainchtein, Ilia D.; De Hosson, Jeff Th M.; Zhou, Yu

    The effects of magnesium aluminum silicate (MAS) glass on the thermal shock resistance and the oxidation behavior of h-BN matrix composites were systematically investigated at temperature differences from 600 degrees C up to 1400 degrees C. The retained strength rate of the composites rose with the

  8. Tissue levels of iron, copper, zinc and magnesium in iron deficient rats

    African Journals Online (AJOL)

    The effects of iron deficiency on the levels of iron, copper, zinc and magnesium in the brain, liver, kidney, heart and lungs of albino rats (Rattus novergicus) was investigated. Forty rats were divided into two groups and the first group was fed a control diet containing 1.09g iron/kg diet while the test group was fed diet ...

  9. Tempering effect on corrosion performance of magnesium alloys for biomedical applications

    NARCIS (Netherlands)

    Zhang, X.; Ferrari, G.M.; Erinc, M.; Sillekens, W.H.

    2010-01-01

    The corrosion resistances for magnesium alloys AZ80, AE82 and ZM21 treated at 200 and 330°C for 2 hours, and for AZ80 and AE82 at 415°C for 8 hours were investigated using potentiodynamic polarization measurements in simulated body fluid (SBF) solution at 37°C. The morphology and the Volta potential

  10. Corrosion protection of AM60B magnesium alloy by application of ...

    Indian Academy of Sciences (India)

    Cerium–vanadium (Ce–V) conversion coating was proposed as a new pretreatment for application of electroless Ni–P coating on AM60B magnesium alloy to replace the traditional chromium oxide pretreatment. Morphology and chemical composition of the conversion coating were investigated. The subsequent Ni–P ...

  11. Phase compositions in magnesium-rare earth alloys containing yttrium, gadolinium or dysprosium

    Energy Technology Data Exchange (ETDEWEB)

    Apps, P.J.; Karimzadeh, H.; King, J.F.; Lorimer, G.W

    2003-03-03

    Phase compositions have been investigated, using thin foil energy dispersive X-ray spectroscopy, in three magnesium-rare earth alloys, containing yttrium, gadolinium or dysprosium. Compositions are suggested for the as-cast eutectic and {beta} precipitate phases and possible compositions for the {beta}{sub 1} precipitate phases are discussed.

  12. Microstructure of high-pressure die-casting AM50 magnesium alloy

    OpenAIRE

    R. Dabrowski; K.N. Braszczynska -Malik; J. Braszczynski

    2009-01-01

    Microstructure analyses of high-pressure die-casting AM50 magnesium alloy are presented. Investigated pressure casting wasproduced on a cold chamber die-casting machine with locking force at 1100 tones in “FINNVEDEN Metal Structures”. Light microscopyand X-ray phase analysis techniques were used to characterize the obtained material. In microstructure, an

  13. R-HPDC of magnesium alloys

    CSIR Research Space (South Africa)

    Curle, UA

    2013-01-01

    Full Text Available different magnesium alloys (AM50A, AM60B, AZ91D) in a first attempt. All as-cast microstructures are characterised more by rosette shaped globules of the primary-(Mg) phase together with Mg(sub17)Al(sub12) as evidence of nonequilibrium cooling rates. Surface...

  14. Magnesium Oxide Induced Metabolic Alkalosis in Cattle

    Science.gov (United States)

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

    1983-01-01

    A study was designed to compare the metabolic alkalosis produced in cattle from the use of an antacid (magnesium oxide) and a saline cathartic (magnesium sulphate). Six, mature, normal cattle were treated orally with a magnesium oxide (MgO) product and one week later given a comparable cathartic dose of magnesium sulphate (MgSO4). The mean percent dry matter content of the cattle feces changed significantly (Pmetabolic alkalosis as determined by base excess values. The base excess values remained elevated for 24 hours in the MgO treated group compared to only 12 hours after MgSO4 administration. Following MgO administration, mean hydrogen ion concentration (pH), bicarbonate ion concentration ([HCO3-]) and base excess were 7.44, 33.3 mmol/L and +8.0 respectively compared to 7.38, 27 mmol/L and +3.0 after MgSO4. Since the oral use of MgO in normal cattle causes a greater and more prolonged metabolic alkalosis compared to MgSO4, MgO is contraindicated as a cathartic in normal cattle or in cattle with abomasal abnormalities characterized by pyloric obstruction and metabolic alkalosis. PMID:6883181

  15. Cathodoluminescence study of vickers indentations in magnesium ...

    African Journals Online (AJOL)

    Vickers diamond pyramid indentations made in single crystal of magnesium oxide (MgO) were examined in an environmental scanning electron microscope interfaced with an AVS-2000 spectrophotometer for luminescence. Three distinct zones around the indentations were identified to exhibit cathodoluminescence, which ...

  16. Intravenous and intramuscular magnesium sulphate regimens in ...

    African Journals Online (AJOL)

    1993-09-03

    Sep 3, 1993 ... parenterally, usually according to one of two popular regimens: the intramuscular (IM) regimen introduced by. Pritchard' and a continuous intravenous (IV) infusion described by Zuspan! Sibai et a/.3 have reported that lower serum magnesium values are achieved with Zuspan's regimen (maintenance dose ...

  17. Magnesium hydrides and their phase transitions

    Czech Academy of Sciences Publication Activity Database

    Paidar, Václav

    2016-01-01

    Roč. 41, č. 23 (2016), s. 9769-9773 ISSN 0360-3199 R&D Projects: GA MŠk(CZ) LD13069 Institutional support: RVO:68378271 Keywords : hydrogen * magnesium and transition metal hydrides * crystal structure stability * displacive phase transformations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.582, year: 2016

  18. Short Communication - Blood Magnesium levels in migraineurs ...

    African Journals Online (AJOL)

    Introduction: Some probable mechanisms have been described to the relationship between magnesium (Mg) level and migraine headache attacks. In the study reported here, we sought to determine the total Mg serum status of patients with migraine within and between the headache attacks and compare it with ...

  19. Regulation of magnesium reabsorption in DCT.

    NARCIS (Netherlands)

    Xi, Q.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2009-01-01

    The distal convoluted tubule (DCT) is the shortest segment of the nephron and consists of an early (DCT1) and late part (DCT2). Here, several transport proteins, like the thiazide-sensitive NaCl cotransporter (NCC) and the epithelial magnesium (Mg(2+)) channel (TRPM6), are exclusively expressed.

  20. Friction phenomena in hydrostatic extrusion of magnesium

    NARCIS (Netherlands)

    Moodij, Ellen

    2014-01-01

    When magnesium is hydrostatically extruded an inconsistent and sometimes bad surface quality is encountered. In hydrostatic extrusion the billet is surrounded by a lubricant, usually castor oil. The required pressure to deform the material is applied onto this lubricant and not directly to the