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Sample records for biology investigating magnesium

  1. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    Directory of Open Access Journals (Sweden)

    Berat Barıs BULDUM

    2013-01-01

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

  2. 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.

  3. Magnesium

    Science.gov (United States)

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

  4. Thermal analytical investigations of the magnesium alloy AZ91

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    K.N. Braszczyńska - Malik

    2007-04-01

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

  5. The biological effects of magnesium-leached chrysotile asbestos.

    Science.gov (United States)

    Morgan, A.; Davies, P.; Wagner, J. C.; Berry, G.; Holmes, A.

    1977-01-01

    Chrysotile asbestos was leached in N hydrochloric acid for varying times to produce a range of magnesium-depleted samples. The protein adsorptive capacity, the haemolytic activity, and the capacity to cause selective release of acid hydrolases from macrophages were measured for the various samples in vitro. The carcinogenicity of the same materials was determined following intrapleural inoculation in rats. The adsorptive capacity for albumin decreased linearly with magnesium removal. The haemolytic activity also declined until about half the magnesium had been removed, after which there was little further change. The selective release of acid hydrolases from macrophages in culture increased up to the point at which half the magnesium had been removed but by 90% depletion had declined rapidly. The carcinogenicity of 50% -depleted chrysotile was similar to that of intact, but at 90% depletion the incidence of mesothelial tumours had fallen considerably. There was no evidence that the leached samples fragmented more than the unleached in vivo. Images Fig. 1 PMID:588440

  6. Investigation of k-struvite formation in magnesium phosphate cements

    OpenAIRE

    LE ROUZIC, Mathieu; Chaussadent, Thierry; Stefan, Lavinia; PLATRET, Gérard

    2014-01-01

    Magnesium phosphate cements can be used as an alternative of Portland cements for the stabilization/solidification (S/S) process of specific wastes like mercury, lead, … These cements are based on the reaction between magnesium oxide (MgO) and monopotassium phosphate (KH2PO4) mixed with water which leads to the formation of the solid skeleton of the matrix: MgO + KH2PO4 + 5H2O  MgKPO4.6H2O. The development of k-struvite crystals (MgKPO4.6H2O) leads to the setting of these ...

  7. DNA Barcoding Investigations Bring Biology to Life

    Science.gov (United States)

    Musante, Susan

    2010-01-01

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

  8. Experimental investigations of an ionic-liquid-based, magnesium ion conducting, polymer gel electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, G.P.; Hashmi, S.A. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2009-02-15

    Studies on a novel magnesium ion conducting gel polymer electrolyte based on a room temperature ionic liquid (RTIL) is reported. It comprises a Mg-salt, Mg(CF{sub 3}SO{sub 3}){sub 2} [or magnesium triflate, Mg(Tf){sub 2}] solution in an ionic liquid, 1-ethyl-3-methylimidazolium trifluoro-methanesulfonate (EMITf), immobilized with poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), which is a freestanding, semitransparent and flexible film with excellent mechanical strength. Physical and electrochemical analyses demonstrate promising characteristics of these films, suitable as electrolytes in rechargeable magnesium batteries. The material offers a maximum electrical conductivity of {proportional_to}4.8 x 10{sup -3} S cm{sup -1} at room temperature (20 C) with excellent thermal and electrochemical stabilities. Possible conformational changes in the polymer host PVdF-HFP due to ionic liquid solution entrapment and ion-polymer interaction are investigated by Fourier transform infra-red (FTIR), X-ray diffraction (XRD) and scanning electron microscopic (SEM) methods. The Mg{sup 2+} ion transport in the gel film is confirmed from cyclic voltammetry, impedance and transport number measurements. The Mg{sup 2+} ion transport number (t{sub +}) is {proportional_to}0.26, which indicates a substantial contribution of triflate anion transport along with ionic conduction due to the component ions of the ionic liquid. (author)

  9. Experimental investigations of an ionic-liquid-based, magnesium ion conducting, polymer gel electrolyte

    Science.gov (United States)

    Pandey, G. P.; Hashmi, S. A.

    Studies on a novel magnesium ion conducting gel polymer electrolyte based on a room temperature ionic liquid (RTIL) is reported. It comprises a Mg-salt, Mg(CF 3SO 3) 2 [or magnesium triflate, Mg(Tf) 2] solution in an ionic liquid, 1-ethyl-3-methylimidazolium trifluoro-methanesulfonate (EMITf), immobilized with poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), which is a freestanding, semitransparent and flexible film with excellent mechanical strength. Physical and electrochemical analyses demonstrate promising characteristics of these films, suitable as electrolytes in rechargeable magnesium batteries. The material offers a maximum electrical conductivity of ∼4.8 × 10 -3 S cm -1 at room temperature (20 °C) with excellent thermal and electrochemical stabilities. Possible conformational changes in the polymer host PVdF-HFP due to ionic liquid solution entrapment and ion-polymer interaction are investigated by Fourier transform infra-red (FTIR), X-ray diffraction (XRD) and scanning electron microscopic (SEM) methods. The Mg 2+ ion transport in the gel film is confirmed from cyclic voltammetry, impedance and transport number measurements. The Mg 2+ ion transport number (t +) is ∼0.26, which indicates a substantial contribution of triflate anion transport along with ionic conduction due to the component ions of the ionic liquid.

  10. Preparation and characterization of porous magnesium materials

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  11. Determination of total magnesium in biological samples using electrothermal atomic absorption spectrometry

    Science.gov (United States)

    Hulanicki, Adam; Godlewska, Beata; Brzóska, Malgorzata

    1995-11-01

    Magnesium content is an important diagnostic parameter in medicine. It is recognized that its determination in one compartment is not sufficient for reliable information about the magnesium status in the body. In addition to the common procedures of magnesium determination in blood by flame atomic absorption spectrometry, the procedure of electrothermal atomization has also been developed and applied to the analysis of blood fractions, mononuclear cells and isolated nuclei of liver cells. Electrothermal atomization is preferred in cases where the sample size is limited and the magnesium content low. The total errors are in the order of 3-4%. Various techniques of sample pretreatment have been tested and direct dilution with 0.05 mol l -1 nitric acid was optimal when the samples were not mineralized. The calibration graph based on standards containing albumin was found to give the best results, as the form of magnesium in the samples may influence the ashing and atomization processes. Good agreement was obtained for determination of magnesium in standard serum. The results are compared with those obtained by the standard flame atomization technique.

  12. Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices

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    Xiaoling Liu

    2013-01-01

    Full Text Available Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+ in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM. The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM and X-ray diffraction (XRD analysis, respectively. The roughness of the coatings was seen to increase from 40±1 nm to 80±1 nm. The mechanical properties (tensile strength and modulus of fibre with coatings decreased with increased magnesium coating thickness.

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

    Institute of Scientific and Technical Information of China (English)

    H.Y. Wang; Z.J. Li

    2006-01-01

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

  14. Nutrition and magnesium absorption.

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

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

  15. 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 ...

  16. Investigation of corrosion behaviour of magnesium alloy AM60B-F under pseudo-physiological conditions

    Energy Technology Data Exchange (ETDEWEB)

    Levesque, J.; Mantovani, D. [Dept. of Mining, Metallurgy and Materials Engineering, Laval Univ., PQ (Canada); Lab. for Biomaterials and Bioengineering, St-Francois-d' Assise Hospital, PQ (Canada); Dube, D.; Fiset, M. [Dept. of Mining, Metallurgy and Materials Engineering, Laval Univ., PQ (Canada)

    2003-07-01

    Endovascular stents have proven effective in treating coronary and peripheral arterial occlusions. All metallic materials currently used to make these devices are considered to be corrosion-resistant, and are therefore implanted on a long-term basis. Complications, however, have often been reported, such as restenosis and thrombosis. To reduce the risk of thrombus formation and restenosis, it would be useful to develop a new family of degradable stents. In fact, in most clinical cases, the occluded artery requires a stent only for a period of up to one year. Interesting candidate materials for manufacture of degradable stents include magnesium alloys, magnesium being an element that is essential to the organism and has a high electronegative potential. Success in using magnesium alloys for making endovascular devices is closely related to the properties of the selected alloy. Ideally, the alloy should degrade slowly, be ductile, be non-toxic, and corrode uniformly. Given these desired properties, we investigated the potential of magnesium alloys as degradable endovascular biomaterials. A test bench was designed and evaluated to reproduce the physiological conditions encountered in coronary arteries. (orig.)

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

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

  18. Spectroscopic and catalytic investigations of VxOy/SBA-15 and magnesium vanadate model catalysts for selective propene oxidation

    OpenAIRE

    Walter, Anke

    2011-01-01

    The objective of the present work was elucidating structure-activity relationships concerning the individual role of vanadium sites in selective propene oxidation. Two suitable vanadium oxide model catalyst systems were employed: vanadium oxides supported on SBA-15, “VxOy/SBA-15”, and various magnesium vanadate phases. Detailed investigations on the preparation, thermal stability, structure, and structural evolution under reducing and propene oxidizing condition were conducted. Various in sit...

  19. 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.

  20. Estimation of calcium, magnesium, cadmium, and lead in biological samples from paralyzed quality control and production steel mill workers.

    Science.gov (United States)

    Afridi, Hassan Imran; Talpur, Farah Naz; Kazi, Tasneem Gul; Kazi, Naveed; Arain, Sadaf Sadia; Shah, Faheem

    2015-06-01

    The determination of trace and toxic metals in the biological samples of human beings is an important clinical screening procedure. The aim of the present study was to compare the level of essential trace and toxic elements cadmium (Cd), calcium (Ca), lead (Pb), and magnesium (Mg) in biological samples (whole blood, urine, and scalp hair) of male paralyzed production (PPW) and quality control workers (PQW) of a steel mill, age ranged (35-55 years). For comparison purposes, healthy age-matched exposed referent subjects (EC), working in steel mill and control subjects (NEC), who were not working in industries and lived far away from the industrial areas, were selected as control subjects. The concentrations of electrolytes and toxic elements in biological samples were measured by atomic absorption spectrometry after microwave-assisted acid digestion. The validity and accuracy of the methodology were checked using certified reference materials. The results of this study showed that the mean values of Cd and Pb were significantly higher in scalp hair, blood, and urine samples of PPW and PQW as compared to NEC and EC (p urine samples of PPW and PQW. The results show the need for immediate improvements in workplace, ventilation, and industrial hygiene practices.

  1. Magnesium Oxide

    Science.gov (United States)

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

  2. Magnesium Modulates Doxorubicin Activity through Drug Lysosomal Sequestration and Trafficking.

    Science.gov (United States)

    Trapani, Valentina; Luongo, Francesca; Arduini, Daniela; Wolf, Federica I

    2016-03-21

    Magnesium is directly involved in the control of cell growth and survival, but its role in cancer biology and therapy is multifaceted; in particular, it is highly controversial whether magnesium levels can affect therapy outcomes. Here we investigated whether magnesium availability can modulate cellular responses to the widely used chemotherapeutic doxorubicin. We used an in vitro model consisting of mammary epithelial HC11 cells and found that high magnesium availability was correlated with diminished sensitivity both in cells chronically adapted to high magnesium concentrations and in acutely magnesium-supplemented cells. This decrease in sensitivity resulted from reduced intracellular doxorubicin accumulation in the face of a similar drug uptake rate. We observed that high-magnesium conditions caused a decrease in intracellular drug retention by altering drug lysosomal sequestration and trafficking. In our model, magnesium supplementation correspondingly modulated expression of the TRPM7 channel, which is known to control cytoskeletal organization and dynamics and may be involved in the proposed mechanism. Our findings suggest that magnesium supplementation in hypomagnesemic cancer patients may hinder response to therapy.

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

    Science.gov (United States)

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

    2015-06-17

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

  4. Adaptable data management for systems biology investigations

    Directory of Open Access Journals (Sweden)

    Burdick David

    2009-03-01

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

  5. 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...

  6. 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.

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

    Institute of Scientific and Technical Information of China (English)

    M.Laleh; Farzad Kargar; A.Sabour Rouhaghdam

    2012-01-01

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

  8. In vitro biological and tribological properties of transparent magnesium aluminate (Spinel) and aluminum oxynitride (ALON®).

    Science.gov (United States)

    Bodhak, Subhadip; Balla, Vamsi Krishna; Bose, Susmita; Bandyopadhyay, Amit; Kashalikar, Uday; Jha, Santosh K; Sastri, Suri

    2011-06-01

    The purpose of this first generation investigation is to evaluate the in vitro cytotoxicity, cell-materials interactions and tribological performance of Spinel and ALON® transparent ceramics for potential wear resistant load bearing implant applications. Besides their non-toxicity, the high surface energy of these ceramics significantly enhanced in vitro cell-materials interactions compared to bioinert commercially pure Ti as control. These transparent ceramics with high hardness in the range of 1334 and 1543 HV showed in vitro wear rate of the order of 10⁻⁶ mm³ Nm⁻¹ against Al₂O₃ ball at a normal load of 20 N.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-03-01

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

  10. Magnesium Test

    Science.gov (United States)

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

  11. 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 ...

  12. Laboratory investigations in cell biology. Second edition

    Energy Technology Data Exchange (ETDEWEB)

    Bregman, A.A.

    1987-01-01

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

  13. Mechanisms of plastic deformation in AZ31 magnesium alloy investigated by acoustic emission and transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Janecek, Milos [Charles University, Faculty of Mathematics and Physics, Ke Karlovu 5, CZ-121 16 Prague 2 (Czech Republic)], E-mail: janecek@met.mff.cuni.cz; Kral, Robert [Charles University, Faculty of Mathematics and Physics, Ke Karlovu 5, CZ-121 16 Prague 2 (Czech Republic); Dobron, Patrik [Charles University, Faculty of Mathematics and Physics, Ke Karlovu 5, CZ-121 16 Prague 2 (Czech Republic); Chmelik, Frantisek [Charles University, Faculty of Mathematics and Physics, Ke Karlovu 5, CZ-121 16 Prague 2 (Czech Republic); Supik, Vladimir [Department of Physical Metallurgy and Materials Technology, Technical University of Brandenburg at Cottbus, D-03010 Cottbus (Germany); Hollaender, Frank [Department of Physical Metallurgy and Materials Technology, Technical University of Brandenburg at Cottbus, D-03010 Cottbus (Germany)

    2007-07-25

    The effect of deformation conditions on plastic deformation and acoustic emission (AE) in hot-rolled magnesium alloy AZ31 has been investigated in the temperature range of 20-200 deg. C by constant strain rate tensile tests. Two sets of samples differing in the preheating temperature before individual passes of hot rolling have been studied. Both the yield stress and the tensile strength decrease with increasing temperature of deformation. The ductility was found to increase significantly with increasing temperature of deformation in both specimens. Unstable plastic deformation (Portevin-Le Chatelier effect) has been observed for all used strain rates both at room and elevated temperatures. Plastic instabilities were accompanied by a pronounced AE activity. The AE bursts were correlated with the individual regions of plastic instabilities on the deformation curve. Mechanisms controlling plastic instabilities are suggested respecting the microstructure evolution as observed by optical and transmission electron microscopy.

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

    Science.gov (United States)

    Tzeli, Demeter; Mavridis, Aristides

    2005-12-01

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

  15. 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.

  16. Investigation Into Gas-Sensing Mechanism of Nanostructured Magnesium Aluminate as a Function of Temperature.

    Science.gov (United States)

    Nithyavathy, N; Arunmetha, S; Dhineshbabu, N R; Rajendran, V

    2015-07-01

    In this study, we used a new simple chemical method to synthesise nanostructured magnesium aluminate (NMA) powder. Sol-gel technique followed by sonication was used to develop different sensor samples namely NMA573, NMA873, and NMA1 073 by calcination at temperatures of 573, 873, and 1073 K respectively. Average crystallite size of 18-27 nm and specific surface area of 68.09 to 61.84 m2 g(-1) was obtained for the sensor samples. The existence of functional groups at 800 and 550 cm-1 corresponding respectively to AIO6 group and the lattice vibration of MgO4 stretching were confirmed through FTIR studies; SEM/EDX confirm the spherical morphology with elemental composition Mg, Al and O at different calcination temperatures. UV-Vis absorption spectra show band gap energy as 3.50, 3.48, and 3.44 eV for the sensor samples NMA573, NMA873, and NMA1 073 respectively. The effect of polyethylene glycol on the gas-sensing behaviour was studied in all the sensor samples. In particular, NMA1073 was found to have better resistance and sensor response for CO gas than NMA573 and NMA873. The effect of increase in calcination temperature of the sensor samples on the structural, morphological, optical, and gas response properties were carried out extensively to explore its gas sensing applications.

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

    Science.gov (United States)

    Sanderson, Peter; Naidu, Ravi; Bolan, Nanthi; Lim, Jung Eun; Ok, Yong Sik

    2015-12-15

    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.

  18. Multi-frequency ferromagnetic resonance investigation of nickel nanocubes encapsulated in diamagnetic magnesium oxide matrix

    Science.gov (United States)

    Nellutla, Saritha; Nori, Sudhakar; Singamaneni, Srinivasa R.; Prater, John T.; Narayan, Jagdish; Smirnov, Alex I.

    2016-12-01

    Partially aligned nickel nanocubes were grown epitaxially in a diamagnetic magnesium oxide (MgO:Ni) host and studied by a continuous wave ferromagnetic resonance (FMR) spectroscopy at the X-band (9.5 GHz) from ca. 117 to 458 K and then at room temperature for multiple external magnetic fields/resonant frequencies from 9.5 to 330 GHz. In contrast to conventional magnetic susceptibility studies that provided data on the bulk magnetization, the FMR spectra revealed the presence of three different types of magnetic Ni nanocubes in the sample. Specifically, three different ferromagnetic resonances were observed in the X-band spectra: a line 1 assigned to large nickel nanocubes, a line 2 corresponding to the nanocubes exhibiting saturated magnetization even at ca. 0.3 T field, and a high field line 3 (geff ˜ 6.2) tentatively assigned to small nickel nanocubes likely having their hard magnetization axis aligned along or close to the direction of the external magnetic field. Based on the analysis of FMR data, the latter nanocubes possess an anisotropic internal magnetic field of at least ˜1.0 T in magnitude.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2007-01-01

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

  1. Student-Directed Investigations in Enzymology for Introductory College Biology.

    Science.gov (United States)

    Posner, Herbert B.; Markstein, James A.

    1998-01-01

    Reports on the design and testing of student-directed investigations for use in large enrollment biology courses. Describes a set of experiments that include the preparation and study of the enzyme tyrosinase. (DDR)

  2. Magnesium cinnamate complex, [Mg(cinn)2(H2O)2]n; structural, spectroscopic, thermal, biological and pharmacokinetical characteristics

    Science.gov (United States)

    Puszyńska-Tuszkanow, Mariola; Zierkiewicz, Wiktor; Grabowski, Tomasz; Daszkiewicz, Marek; Maciejewska, Gabriela; Adach, Anna; Kucharska-Ziembicka, Katarzyna; Wietrzyk, Joanna; Filip-Psurska, Beata; Cieślak-Golonka, Maria

    2017-04-01

    The composition and structure of the magnesium complex with cinnamic acid, [Mg(cinn)2(H2O)2]n(1), were determined using single crystal X-ray diffraction data, IR, NMR spectroscopies, thermal and mass spectrometry analysis. Magnesium cinnamate complex, like the isostructural cobalt(II) species reported in the literature, appears to belong to the group of coordination polymers forming layered solids with pseudooctahedral coordination around the metal centre and Osbnd Csbnd O bridging units. The vibrational assignments of the experimental spectra of the complex (1) were performed on the basis of the DFT results obtained for the [Mg(cinn)4(H2O)2]2- ion, serving as a model. The complex was found to exhibit a very low cytotoxicity against neoplastic: A549 (lung), MCF-7 (breast), P388 (murine leukemia) and normal BALB3T3 (mouse fibroblasts) cell lines. In silico pharmacokinetical parameter calculations for (1) and seven known magnesium complexes with carboxylic acids: lactic, malic, glutamic, hydroaspartic and aspartic allowed for comparison of their potential bioavailability. Magnesium cinnamate complex appeared to exhibit a superior lipophilic property that suggests an optimal pharmacokinetics profile.

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

    Institute of Scientific and Technical Information of China (English)

    Elbert David Mai; Huinan Liu

    2014-01-01

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

  4. 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...

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

    Science.gov (United States)

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

    2012-10-01

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

  6. Magnesium as Biodegradable Implant Material

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

  7. Comprehensive investigation of the properties of lanthanum-magnesium hexaluminate single crystals activated by neodymium ions

    Energy Technology Data Exchange (ETDEWEB)

    Agladze, N.I.; Antonov, V.A.; Arsen' ev, P.A.; Bagdasarov, K.S.; Zolin, V.F.

    1986-05-01

    The authors present the results of investigations of the physiochemical and spectroscopic characteristics of LMHA-Nd crystals, as considered on the basis of their spectral-lasing properties. LMHA-Eu is of interest as a luminophore. The authors monitored the completeness of the chemical reaction on a DRON-1 diffractometer. An x-ray analysis was carried out by the method of comparing with the data in the ASTM file of diffraction pictures, obtained in a focusing Guinier-De-Wolf monochromator-camera and a Weisenberg camera. Absorption and luminescence spectra were recorded with SDL-1 and DFS-12 spectrometers and with SF-8 and SPECORD UV-VIS spectrophotometers and in the infrared with a high-resolution Fourier spectrometer. Analysis of the polarized spectra of LMHA-Nd shows that the symmetry of the impurity centers in LMHA is lower than tetragonal and triagonal. The same conclusion follows from an analysis of the luminescence spectra of LMHA-Eu with selective excitation.

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

    Science.gov (United States)

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

    2011-09-01

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

  9. Magnesium substitution in brushite cements.

    Science.gov (United States)

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

    2013-01-01

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

  10. 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.

  11. 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....

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

    Science.gov (United States)

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

    2015-10-01

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

  13. Magnesium and healthy aging.

    Science.gov (United States)

    Veronese, Nicola; Zanforlini, Bruno Micael; Manzato, Enzo; Sergi, Giuseppe

    2015-01-01

    Magnesium (Mg) is relatively stable in the intracellular compartment, although decreases linearly with advancing age. This begs the question as to whether Mg could be used as biomarker of aging. A biomarker of aging is a biological parameter of an organism that, in the absence of disease, better predicts functional capability at a later age than the chronological age. Bone and muscle Mg content might be useful biomarkers, but the need for biopsies and the heterogeneous distribution of Mg in bones and muscles strongly limit the application of these methods in clinical practice. Similar considerations can be made for urinary Mg assessment, particularly after a loading test. Markers of Mg in blood seem fairly unreliable as biomarkers of aging since they are strongly dependent upon renal function, do not reflect the intracellular Mg status, and, in some investigations, are within normal ranges although other Mg parameters are not. Other investigations (e.g. nuclear magnetic resonance with fluorescent probes) seem to be promising, but their availability remains limited.

  14. 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.

  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. 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.

  17. 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.

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

    Science.gov (United States)

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

    2012-03-01

    The magnesium content in food consumed in the Western world is steadily decreasing. Hypomagnesemia is associated with increased incidence of diabetes mellitus, metabolic syndrome, all-cause and coronary artery disease mortality. We investigated the impact of supplemental oral magnesium citrate versus magnesium oxide on intracellular magnesium levels ([Mg2+]i) and platelet function in healthy subjects with no apparent heart disease. In a randomized, prospective, double-blind, crossover study, 41 (20 women) healthy volunteers [mean age 53±8 (range 31-75) years] received either magnesium oxide monohydrate tablets (520 mg/day of elemental magnesium) or magnesium citrate tablets (295.8 mg/day of elemental magnesium) for one month (phase 1), followed by a four-week wash-out period, and then crossover treatment for one month (phase 2). [Mg2+]i was assessed from sublingual cells through x-ray dispersion (normal values 37.9±4.0 mEq/L), serum magnesium levels, platelet aggregation, and quality-of-life questionnaires were assessed before and after each phase. Oral magnesium oxide, rather than magnesium citrate, significantly increased [Mg2+]i (34.4±3 versus 36.3±2 mEq/L, pmagnesium oxide treatment significantly improved [Mg2+]i, total and LDL cholesterol compared with magnesium citrate, while both treatments similarly inhibited platelet aggregation in healthy subjects with no apparent heart disease.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  20. Selenium and magnesium status in fibromyalgia.

    Science.gov (United States)

    Eisinger, J; Plantamura, A; Marie, P A; Ayavou, T

    1994-12-01

    Muscle pain has been associated with magnesium (Mg) and selenium (Se) deficiency: magnesium and selenium status were investigated in fibromyalgia (FM). Erythrocyte (E), leucocyte (L) and serum (S) magnesium, serum selenium and zinc, and vitamin B1, B2, A or E status were assessed in 22 patients with fibromyalgia and in 23 age-matched healthy controls. LMg is significantly increased (P fibromyalgia. These magnesium abnormalities are associated with previously-reported impairment of thiamin metabolism. Antioxidant status (as well as plasma malondialdehyde) is unchanged in fibromyalgia and serum selenium levels, slightly but not significantly correlated with serum magnesium, is normal.

  1. Systems biology approaches and pathway tools for investigating cardiovascular disease

    NARCIS (Netherlands)

    Wheelock, C.E.; Wheelock, A.M.; Kawashima, S.; Diez, D.; Kanehisa, M.; Erk, M. van; Kleemann, R.; Haeggström, J.Z.; Goto, S.

    2009-01-01

    Systems biology aims to understand the nonlinear interactions of multiple biomolecular components that characterize a living organism. One important aspect of systems biology approaches is to identify the biological pathways or networks that connect the differing elements of a system, and examine ho

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

    Science.gov (United States)

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

    2015-01-01

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

  3. Investigating the Efficiency of Biological Filters for Ammonia Removal

    Directory of Open Access Journals (Sweden)

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

    2013-09-01

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

  4. Room temperature magnesium electrorefining by using non-aqueous electrolyte

    Science.gov (United States)

    Park, Jesik; Jung, Yeojin; Kusumah, Priyandi; Dilasari, Bonita; Ku, Heesuk; Kim, Hansu; Kwon, Kyungjung; Lee, Churl Kyoung

    2016-09-01

    The increasing usage of magnesium inevitably leads to a fast increase in magnesium scrap, and magnesium recycling appears extremely beneficial for cost reduction, preservation of natural resources and protection of the environment. Magnesium refining for the recovery of high purity magnesium from metal scrap alloy (AZ31B composed of magnesium, aluminum, zinc, manganese and copper) at room temperature is investigated with a non-aqueous electrolyte (tetrahydrofuran with ethyl magnesium bromide). A high purity (99.999%) of electrorefined magneisum with a smooth and dense surface is obtained after potentiostatic electrolysis with an applied voltage of 2 V. The selective dissolution of magnesium from magnesium alloy is possible by applying an adequate potential considering the tolerable impurity level in electrorefined magnesium and processing time. The purity estimation method suggested in this study can be useful in evaluating the maximum content of impurity elements.

  5. Hemin/G-quadruplex structure and activity alteration induced by magnesium cations.

    Science.gov (United States)

    Kosman, J; Juskowiak, B

    2016-04-01

    The influence of metal cations on G-quadruplex structure and peroxidase-mimicking DNAzyme activity was investigated. Experiments revealed a significant role of magnesium ion, which in the presence of potassium cation influenced DNAzyme activity. This ability has been associated with alteration of G-quadruplex topology and consequently affinity to bind hemin molecule. It has been demonstrated that G-quadruplex based on PS2.M sequence under these conditions formed parallel topology, which exhibited lower activity than that observed in standard potassium-containing solution. On the other hand DNAzyme/magnesium ion system based on telomeric sequence, which did not undergo significant structural changes, exhibited higher peroxidase activity upon magnesium ion addition. In both cases, the stabilization effect of magnesium cations on G-quadruplex structure was observed. The mechanism of DNAzyme activity alteration by magnesium ion can be explained by its influence on the pKa value of DNAzyme. Magnesium ion decreased pKa for PS2.M based system but increased it for telomeric DNAzyme. Magnesium cation effect on G-quadruplex structure as well as DNAzyme activity is particularly important since this ion is one of the most common metal cations in biological samples.

  6. Magnesium in diet

    Science.gov (United States)

    ... sources of magnesium: Fruits or vegetables (such as bananas, dried apricots, and avocados) Nuts (such as almonds ... Supplements, National Institutes of Health. Dietary Supplement Fact Sheet: Magnesium . ods.od.nih.gov/factsheets/Magnesium-Consumer . ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-15

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

  8. Classical investigation of long-range coherence in biological systems

    Science.gov (United States)

    Preto, Jordane

    2016-12-01

    Almost five decades ago, H. Fröhlich [H. Fröhlich, "Long-range coherence and energy storage in biological systems," Int. J. Quantum Chem. 2(5), 641-649 (1968)] reported, on a theoretical basis, that the excitation of quantum modes of vibration in contact with a thermal reservoir may lead to steady states, where under high enough rate of energy supply, only specific low-frequency modes of vibration are strongly excited. This nonlinear phenomenon was predicted to occur in biomolecular systems, which are known to exhibit complex vibrational spectral properties, especially in the terahertz frequency domain. However, since the effects of terahertz or lower-frequency modes are mainly classical at physiological temperatures, there are serious doubts that Fröhlich's quantum description can be applied to predict such a coherent behavior in a biological environment, as suggested by the author. In addition, a quantum formalism makes the phenomenon hard to investigate using realistic molecular dynamics simulations (MD) as they are usually based on the classical principles. In the current paper, we provide a general classical Hamiltonian description of a nonlinear open system composed of many degrees of freedom (biomolecular structure) excited by an external energy source. It is shown that a coherent behaviour similar to Fröhlich's effect is to be expected in the classical case for a given range of parameter values. Thus, the supplied energy is not completely thermalized but stored in a highly ordered fashion. The connection between our Hamiltonian description, carried out in the space of normal modes, and a more standard treatment in the physical space is emphasized in order to facilitate the prediction of the effect from MD simulations. It is shown how such a coherent phenomenon may induce long-range resonance effects that could be of critical importance at the biomolecular level. The present work is motivated by recent experimental evidences of long-lived excited low

  9. 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

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

    Directory of Open Access Journals (Sweden)

    L.M. Lobanov

    2016-06-01

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

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

    Science.gov (United States)

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

    2015-05-01

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

  12. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    A K Misra; Renu Mathur

    2007-06-01

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

  13. Gestational magnesium deficiency is deleterious to fetal outcome.

    Science.gov (United States)

    Almonte, R A; Heath, D L; Whitehall, J; Russell, M J; Patole, S; Vink, R

    1999-07-01

    A number of recent epidemiological findings have implicated magnesium as being essential to fetal well-being. Few studies, however, have examined the relationship between maternal requirements for dietary magnesium and subsequent mortality and morbidity in offspring. The present study uses a rodent model of dietary-induced hypomagnesemia to investigate the effects of magnesium deficiency prior to and during gestation on neonatal morbidity and mortality. Magnesium deficiency during gestation significantly increased neonatal mortality and morbidity. Such increases were associated with a reduced free magnesium concentration in both maternal and offspring blood and an increased incidence of periventricular hemorrhage and edema in newborn pups as observed by magnetic resonance imaging and histology. Animals fed a magnesium-deficient diet before mating but given magnesium supplementation during gestation did not demonstrate a significant change in neonatal mortality and morbidity when compared to control animals. The significant improvement in fetal outcome with dietary magnesium supports the concept of magnesium supplementation during pregnancy.

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

    Directory of Open Access Journals (Sweden)

    Francesca Cecchinato

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

  15. Magnesium in disease

    OpenAIRE

    Geiger, Helmut; Wanner, Christoph

    2012-01-01

    Although the following text will focus on magnesium in disease, its role in healthy subjects during physical exercise when used as a supplement to enhance performance is also noteworthy. Low serum magnesium levels are associated with metabolic syndrome, Type 2 diabetes mellitus (T2DM) and hypertension; consequently, some individuals benefit from magnesium supplementation: increasing magnesium consumption appears to prevent high blood pressure, and higher serum magnesium levels are associated ...

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

    Science.gov (United States)

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

    2015-07-01

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

  17. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  19. 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.

  20. Investigation on inhibition of biological effects of endothelin

    Institute of Scientific and Technical Information of China (English)

    田青; 赵东; 张继峰; 高连如; 刘胜昔; 杨军; 苏静怡; 张肇康; 汤健; 唐朝枢

    1996-01-01

    The effects of a series of substances on the biological function of endothelin (ET) are reported. The substances used are: synthetic inhibitors of endothelium derived relaxing factors (EDRFs), inhibitor of big-endothelin converting enzyme phosphoramidon, antiserum of endothelin, antagonists of endothelin A receptor BQ123 and JKC301, and two Chinese anti-snake venom herb medicines Lobelia radians Thumb and Taris polyphylla Smith var. chinensis (Franch) Hara. The results showed that inhibiting the production of nitric oxide (NO) could stimulate ET release from vascular endothelium, elevate plasma ET and increase blood pressure. These changes could be reversed by L-arginine (L-Arg), the substrate of nitric oxide synthase (NOS). The amount of ET released by arterial endothelium could be increased or inhibited by inhibiting or stimulating the synthesis of prostacyclin (PGI2). The plasma ET level and blood pressure in both SHR and WKY rats could be decreased by giving phosphoramidon (PhR). The above results i

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

    Science.gov (United States)

    Cheunkar, Sarawut

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

  2. Spectroscopic investigations of surface deposited biological warfare simulants

    Science.gov (United States)

    Barrington, Stephen J.; Bird, Hilary; Hurst, Daniel; McIntosh, Alastair J. S.; Spencer, Phillippa; Pelfrey, Suzanne H.; Baker, Matthew J.

    2012-06-01

    This paper reports a proof-of-principle study aimed at discriminating biological warfare (BW) simulants from common environmental bacteria in order to differentiate pathogenic endospores in situ, to aid any required response for hazard management. We used FTIR spectroscopy combined with multivariate analysis; FTIR is a versatile technique for the non-destructive analysis of a range of materials. We also report an evaluation of multiple pre-processing techniques and subsequent differences in cross-validation accuracy of two pattern recognition models (Support Vector Machines (SVM) and Principal Component - Linear Discriminant Analysis (PC-LDA)) for two classifications: a two class classification (Gram + ve spores vs. Gram -ve vegetative cells) and a six class classification (bacterial classification). Six bacterial strains Bacillus atrophaeus, Bacillus thuringiensis var. kurstaki, Bacillus thuringiensis, Escherichia coli, Pantaeoa agglomerans and Pseudomonas fluorescens were analysed.

  3. 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

  4. Corrosion behavior of magnesium and magnesium alloys

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  5. Magnesium: Potential Roles in Neurovascular Disease

    Directory of Open Access Journals (Sweden)

    Jason J Chang

    2014-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Oliver Y. Martin

    2012-09-01

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

  7. Malignant mesothelioma, clinical, diagnostic and cell biological investigations

    NARCIS (Netherlands)

    M.A. Versnel (Marjan)

    1989-01-01

    textabstractThe purpose of this study was to improve the diagnosis of human malignant mesothelioma on the one hand and to investigate the growth regulation and transformation of normal and malignant mesothelial cells on the other hand. In this thesis improvement of diagnosis was approached by the se

  8. Choline Magnesium Trisalicylate

    Science.gov (United States)

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

  9. Low magnesium level

    Science.gov (United States)

    Treating the condition that is causing low magnesium can help. If you play sports or do other vigorous activity, drink fluids such as sports drinks that contain electrolytes to keep your magnesium level in a healthy range.

  10. 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.

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

    Science.gov (United States)

    Owczarek, Aleksandra; Gudej, Jan

    2013-01-01

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

  12. Magnesium and Space Flight.

    Science.gov (United States)

    Smith, Scott M; Zwart, Sara R

    2015-12-08

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

  13. Magnesium and Space Flight

    Science.gov (United States)

    Smith, Scott M.; Zwart, Sara R.

    2016-01-01

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

  14. 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.

  15. An investigation into biological recognition coatings for piezoelectric sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Sharron

    2002-07-01

    The concept of harvesting chemicals from nature and employing them with piezoelectric crystals for biosensor development is investigated. Literature is reviewed for information theory relating to molecular structure, biosensors, immobilisation techniques, piezoelectric transducers and biosensor applications of quartz crystals. Three types of molecules were investigated for their biosensing potential, saccharides (pectic acid and alginic acid), an enzyme (galactose oxidase) and an antibody (specific for Botrytis cinerea). Immobilisation procedures using {gamma}-aminopropyltrimethoxy silane, polyethyleneimine and glutaraldehyde cross-linking are developed for pectic acid, alginic acid, galactose oxidase and the Botrytis antibody. These materials are immobilised onto the gold electrode area of an AT-cut quartz crystal microbalance. Operating conditions, either dip and dry batch monitoring or dynamic real-time monitoring using a flow cell are outlined. Ageing of the piezoelectric crystal sensor through erosion of coatings or during physical cleaning of crystals, prior to recoating, is featured and is particularly important to future cost effective commercial piezoelectric crystal sensor systems. Scanning tunnel microscopy is selected and an example from literature is used to evidence possible mechanisms of primary coat bonding to the gold electrodes. The associated cleaning problems and explanation of memory effects are then postulated. Calibrating data with sensitivities and limits of detection are presented for Cu{sup 2+} (pectic acid coating, Cu{sup 2+} range of 0.002mM (0.128ppm) to 0.5mM (32ppm); galactose oxidase coating, Cu{sup 2+} range of 0.002mM (0.128ppm) to 0.5mM (32ppm)); and for Pb{sup 2+} (alginic acid coating, Pb{sup 2+} range of 0.002mM (0.414ppm) to 0.1mM (20.7ppm)). Interference effects of Pb, Co, Ni, Zn, Ca and Mg on Cu{sup 2+} detection and measurement are presented. Similarly interference effects of Cu, Co, Ni, Zn and Ca on Pb{sup 2+} detection

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

    Science.gov (United States)

    Raad, Nawal Abou; Chatila, Hanadi

    2016-01-01

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

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

    Science.gov (United States)

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

    2013-11-01

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

  18. Magnesium and the Athlete.

    Science.gov (United States)

    Volpe, Stella Lucia

    2015-01-01

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

  19. 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

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

    Science.gov (United States)

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

    2015-06-01

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

  1. Effect of magnesium ion on human osteoblast activity

    Directory of Open Access Journals (Sweden)

    L.Y. He

    2016-01-01

    Full Text Available Magnesium, a promising biodegradable metal, has been reported in several studies to increase bone formation. Although there is some information regarding the concentrations of magnesium ions that affect bone remodeling at a cellular level, little is known about the effect of magnesium ions on cell gap junctions. Therefore, this study aimed to systematically investigate the effects of different concentrations of magnesium on bone cells, and further evaluate its effect on gap junctions of osteoblasts. Cultures of normal human osteoblasts were treated with magnesium ions at concentrations of 1, 2 and 3 mM, for 24, 48 and 72 h. The effects of magnesium ions on viability and function of normal human osteoblasts and on gap junction intercellular communication (GJIC in osteoblasts were investigated. Magnesium ions induced significant (P<0.05 increases in cell viability, alkaline phosphate activity and osteocalcin levels of human osteoblasts. These stimulatory actions were positively associated with the concentration of magnesium and the time of exposure. Furthermore, the GJIC of osteoblasts was significantly promoted by magnesium ions. In conclusion, this study demonstrated that magnesium ions induced the activity of osteoblasts by enhancing GJIC between cells, and influenced bone formation. These findings may contribute to a better understanding of the influence of magnesium on bone remodeling and to the advance of its application in clinical practice.

  2. 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.

  3. Systematically biological prioritizing remediation sites based on datasets of biological investigations and heavy metals in soil

    Science.gov (United States)

    Lin, Wei-Chih; Lin, Yu-Pin; Anthony, Johnathen

    2015-04-01

    Heavy metal pollution has adverse effects on not only the focal invertebrate species of this study, such as reduction in pupa weight and increased larval mortality, but also on the higher trophic level organisms which feed on them, either directly or indirectly, through the process of biomagnification. Despite this, few studies regarding remediation prioritization take species distribution or biological conservation priorities into consideration. This study develops a novel approach for delineating sites which are both contaminated by any of 5 readily bioaccumulated heavy metal soil contaminants and are of high ecological importance for the highly mobile, low trophic level focal species. The conservation priority of each site was based on the projected distributions of 6 moth species simulated via the presence-only maximum entropy species distribution model followed by the subsequent application of a systematic conservation tool. In order to increase the number of available samples, we also integrated crowd-sourced data with professionally-collected data via a novel optimization procedure based on a simulated annealing algorithm. This integration procedure was important since while crowd-sourced data can drastically increase the number of data samples available to ecologists, still the quality or reliability of crowd-sourced data can be called into question, adding yet another source of uncertainty in projecting species distributions. The optimization method screens crowd-sourced data in terms of the environmental variables which correspond to professionally-collected data. The sample distribution data was derived from two different sources, including the EnjoyMoths project in Taiwan (crowd-sourced data) and the Global Biodiversity Information Facility (GBIF) ?eld data (professional data). The distributions of heavy metal concentrations were generated via 1000 iterations of a geostatistical co-simulation approach. The uncertainties in distributions of the heavy

  4. 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.

  5. Recycling of magnesium drive train components

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  6. Recycling of magnesium drive train components

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  7. Chromatography methods in investigation of lipophilicity of the biological active substances

    OpenAIRE

    Odović Jadranka V.; Trbojević-Stanković Jasna B.

    2009-01-01

    This paper presents the review of the methods used in research of the biological active substances hydrophobicity, a very important property. The biological activity of some substances depends on their pharmacokinetics and pharmacodynamics. These processes depend on the molecule's capability to interact with two different media: aqueous (cells interior) and non-aqueous (cells membrane), or on the molecule lipophilicity. Today, great attention is given to investigation and systematic determina...

  8. 75 FR 38983 - Magnesium Metal From the People's Republic of China and the Russian Federation: Final Results of...

    Science.gov (United States)

    2010-07-07

    ... International Trade Administration Magnesium Metal From the People's Republic of China and the Russian... magnesium metal from the People's Republic of China (``PRC'') and the Russian Federation (``Russia... Magnesium LLS, the petitioner in the magnesium metal investigation, notified the Department that it...

  9. Investigating the role of retinal Müller cells with approaches in genetics and cell biology.

    Science.gov (United States)

    Fu, Suhua; Zhu, Meili; Ash, John D; Wang, Yunchang; Le, Yun-Zheng

    2014-01-01

    Müller cells are major macroglia and play many essential roles as a supporting cell in the retina. As Müller cells only constitute a small portion of retinal cells, investigating the role of Müller glia in retinal biology and diseases is particularly challenging. To overcome this problem, we first generated a Cre/lox-based conditional gene targeting system that permits the genetic manipulation and functional dissection of gene of interests in Müller cells. To investigate diabetes-induced alteration of Müller cells, we recently adopted methods to analyze Müller cells survival/death in vitro and in vivo. We also used normal and genetically altered primary cell cultures to reveal the mechanistic insights for Müller cells in biological and disease processes. In this article, we will discuss the applications and limitations of these methodologies, which may be useful for research in retinal Müller cell biology and pathophysiology.

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

    Science.gov (United States)

    Foote, Linda C.; Fitzpatrick, Kathleen A.

    2004-01-01

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

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

    Science.gov (United States)

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

    2008-01-01

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

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-04-15

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

  14. 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...

  15. Immunological Response to Biodegradable Magnesium Implants

    Science.gov (United States)

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

    2014-04-01

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

  16. Growth Habit of the Basic Oxysulfate Magnesium Whisker

    Institute of Scientific and Technical Information of China (English)

    WU Jiansong; GAO Yimin

    2016-01-01

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

  17. Chromatography methods in investigation of lipophilicity of the biological active substances

    Directory of Open Access Journals (Sweden)

    Odović Jadranka V.

    2009-01-01

    Full Text Available This paper presents the review of the methods used in research of the biological active substances hydrophobicity, a very important property. The biological activity of some substances depends on their pharmacokinetics and pharmacodynamics. These processes depend on the molecule's capability to interact with two different media: aqueous (cells interior and non-aqueous (cells membrane, or on the molecule lipophilicity. Today, great attention is given to investigation and systematic determination of drugs lipophilicity. In these researches chromatography methods have an important role.

  18. Development and investigation of MOEMS type displacement-pressure sensor for biological information monitoring

    Science.gov (United States)

    Ostasevicius, Vytautas; Malinauskas, Karolis; Janusas, Giedrius; Palevicius, Arvydas; Cekas, Elingas

    2016-04-01

    The aim of this paper is to develop and investigate MOEMS displacement-pressure sensor for biological information monitoring. Developing computational periodical microstructure models using COMSOL Multiphysics modeling software for modal and shape analysis and implementation of these results for design MOEMS displacement-pressure sensor for biological information monitoring was performed. The micro manufacturing technology of periodical microstructure having good diffraction efficiency was proposed. Experimental setup for characterisation of optical properties of periodical microstructure used for design of displacement-pressure sensor was created. Pulsating human artery dynamic characteristics in this paper were analysed.

  19. 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.

  20. Optimization of Magnesium Metal into Commercially Pure Aluminium

    Directory of Open Access Journals (Sweden)

    Vandana J Rao

    2014-02-01

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

  1. 磷酸镁骨黏合剂的生物安全性研究%Biological safety of magnesium phosphate bone cement

    Institute of Scientific and Technical Information of China (English)

    张秉文; 俞永林; 刘昌胜; 黄煌渊

    2011-01-01

    OBJECTIVE To examine whether the material and its metabolites have an impact on the surrounding tissue and test whether its biocompatibility is good or not. METHODS In vitro cytotoxicity test was performed,MTT Test Group: the mouse osteoblasts was adopted to make cell suspension with different concentrations of MPC extract and observed for 1, 3 and 5 days by adding MTT, DMSO, the absorbance was measured and the cell relative growth rate (RGR) was calculated, and toxicity was graded. ALP Test: the mouse osteoblasts was adopted to make cell suspension with different concentrations of MPC extract for the study group, phenol standard solution was selected as the standard group, double-distilled water was as a blank control group, normal 10%DMEM cell culture medium as negative the control group. After the observation for 1, 3, 5 days, alkaline phosphatase was used to detect, the light absorption value of phenol content was calculated. Inflammatory cytokine expression tests: the mouse osteoblasts and the producing cell suspension of different concentrations of MPC were mixed as a pilot group of extracts, cell culture medium was used as negative control, the ELISA of inflammatory factors of IL-1β, IL-6 and TNF-α were determinated by double antibody sandwich after the observation for1, 3 and 5 days. RESULTS MTT test showed cell toxicity gradings were 0 ~ 1; different concentrations of MPC leaching solution had no effect on cell growth; ALP detection tests: different concentrations of MPC extract had no statistically significant differences; Inflammatory cytokine expression test:different concentrations of MPC extracts were compared with the negative control group, there was no statistically significant difference, which showed the molecular level would not promote the expression of inflammatory factors. CONCLUSIONS Magnesium phosphate cement on the osteoblast cells has no significant impact on the cells and no significant toxicity, but has a good cell compatibility

  2. Magnesium Aluminate Spinel

    Institute of Scientific and Technical Information of China (English)

    Yu Lingyan

    2012-01-01

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

  3. 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 ...

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

    Directory of Open Access Journals (Sweden)

    Behij Souheil

    2013-01-01

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

  5. Validation of Procedures for Monitoring Crewmember Immune Function - Short Duration Biological Investigation

    Science.gov (United States)

    Sams, Clarence; Crucian, Brian; Stowe, Raymond; Pierson, Duane; Mehta, Satish; Morukov, Boris; Uchakin, Peter; Nehlsen-Cannarella, Sandra

    2008-01-01

    Validation of Procedures for Monitoring Crew Member Immune Function - Short Duration Biological Investigation (Integrated Immune-SDBI) will assess the clinical risks resulting from the adverse effects of space flight on the human immune system and will validate a flightcompatible immune monitoring strategy. Immune system changes will be monitored by collecting and analyzing blood, urine and saliva samples from crewmembers before, during and after space flight.

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

    Science.gov (United States)

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

    2009-09-01

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

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

    Science.gov (United States)

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

    2014-12-01

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

  8. Adsorption of diazinon and fenitrothion on nanocrystalline magnesium oxides

    Directory of Open Access Journals (Sweden)

    Mahsa Armaghan

    2017-01-01

    Full Text Available Nanocrystalline magnesium oxide was prepared by the sol–gel method from magnesium methoxide and characterized by Fourier transform infrared spectroscopy, thermal analysis, X-ray powder diffraction and transmission electron microscopy. Sol–gel derived nanocrystalline magnesium oxide along with a commercial nanocrystalline magnesium oxide was used as adsorbents to study the adsorption of two common, organophosphorous pesticides, diethoxy-[(2-isopropyl-6-methyl-4-pyrimidinyloxy]-thioxophosphorane (diazinon and dimethoxy-(3-methyl-4-nitrophenoxy-thioxophosphorane (fenitrothion. Adsorption of diazinon and fenitrothion on the sol–gel derived, and commercial nanocrystalline magnesium oxides was studied using UV–vis, FT-IR and 31P NMR spectroscopies. The effect of hydroxyl groups on edge/corner and flat panel of magnesium oxide in adsorption of diazinon and fenitrothion was investigated. The results showed that the adsorption of diazinon on the sol–gel derived nanocrystalline magnesium oxide is destructive whereas on commercial one is non-destructive. Commercial nanocrystalline magnesium oxide showed higher activity in the adsorption of fenitrothion than the sol–gel derived, and adsorptions on both nanocrystalline magnesium oxides are destructive.

  9. Effect of Magnesium Hydride on the Corrosion Behavior of Pure Magnesium in 0.1 M NaCl Solution

    Directory of Open Access Journals (Sweden)

    Shanna Xu

    2010-01-01

    Full Text Available The effect of magnesium hydride on the corrosion behavior of pure magnesium in 0.1 M NaCl solution was investigated using the gas collection method, potentiostatic current decay test, and in situ Raman spectrum. The formation of magnesium hydride (MgH2, Mg2H4 was observed at the cathodic region. Applying anodic potential leads to decomposition of magnesium hydride. Magnesium hydride plays an important role on the negative difference effect (NDE in both the cathodic and anodic regions.

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

    Science.gov (United States)

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

    2012-09-24

    Beyond hydrogen storage: The first example of reversible magnesium deposition/stripping onto/from an inorganic salt was seen for a magnesium borohydride electrolyte. High coulombic efficiency of up to 94 % was achieved in dimethoxyethane solvent. This Mg(BH(4))(2) electrolyte was utilized in a rechargeable magnesium battery.

  11. Experimental and theoretical investigations of lithium and magnesium derivatives of bis(tert-butylamido)cyclodiphosph(III/V)- and (V/V)azane mono- and ditellurides.

    Science.gov (United States)

    Briand, Glen G; Chivers, Tristram; Parvez, Masood; Schatte, Gabriele

    2003-01-27

    Deprotonation of bis(tert-butylamido)cyclophosph(III/III)azane with organolithium or organomagnesium reagents followed by oxidation with elemental tellurium is a viable approach to the preparation of metal cyclodiphosphazane mono- and ditellurides. The reaction of the cyclodiphosph(III)azane [tBu(H)NP(mu-NtBu)2PN(H)tBu] (1) with elemental tellurium in boiling toluene affords the monotelluride [tBu(H)N(Te)P(mu-NtBu)2PN(H)tBu] (9). A similar reaction involving the magnesium salt Mg[tBuNP(mu-NtBu)2PNtBu](THF)2 (2) also yields a monotelluride Mg[tBuN(Te)P(mu-NtBu)2PNtBu]-(THF)2 (10). By contrast, reaction of the lithium salt Li2[tBuNP(mu-NtBu)2PNtBu](THF)2 (3) with tellurium results in double oxidation and the formation of the ditellurides Li2[tBuN(Te)P(mu-NtBu)2P(Te)NtBu](THF)4 (11) and Li2-[tBuN(Te)P(mu-NtBu)2P(Te)NtBu](tmeda)2 (12). Compounds 9-12 have been characterized by multinuclear (1H, 7Li, 13C, 31P, and 125Te) NMR, while 9, 10, and 12 have also been characterized by X-ray crystallography. The structure of 9 reveals a typical cis/endo, exo arrangement, with no intermolecular contacts to tellurium. The seco-heterocubic structure, observed in 2, is retained in 10, with the ligand chelating magnesium in an N,N',N"-manner. Unique coordination behavior is exhibited by the ditelluride 12, in which the dianionic ligand is attached to the two lithium centers in both Te,Te' and Te,N bonding modes. Multinuclear NMR data are consistent with retention of the solid-state structures of 9-12 in solution at low temperatures. The reactivity of cyclodiphosph(III/III)azanes toward chalcogens is rationalized by using theoretical calculations (semiempirical PM3 level of theory), which show an inverse correlation between the charge at the phosphorus center and the ease of oxidation.

  12. Mechanisms of magnesium-induced vasodilation in cerebral penetrating arterioles.

    Science.gov (United States)

    Murata, Takahiro; Dietrich, Hans H; Horiuchi, Tetsuyoshi; Hongo, Kazuhiro; Dacey, Ralph G

    2016-06-01

    We investigated in cerebral penetrating arterioles the signaling mechanisms and dose-dependency of extracellular magnesium-induced vasodilation and also its vasodilatory effects in vessels preconstricted with agonists associated with delayed cerebral vasospasm following SAH. Male rat penetrating arterioles were cannulated. Their internal diameters were monitored. To investigate mechanisms of magnesium-induced vasodilation, inhibitors of endothelial function, potassium channels and endothelial impairment were tested. To simulate cerebral vasospasm we applied several spasmogenic agonists. Increased extracellular magnesium concentration produced concentration-dependent vasodilation, which was partially attenuated by non-specific calcium-sensitive potassium channel inhibitor tetraethylammonium, but not by other potassium channel inhibitors. Neither the nitric oxide synthase inhibitor L-NNA nor endothelial impairment induced by air embolism reduced the dilation. Although the magnesium-induced vasodilation was slightly attenuated by the spasmogen ET-1, neither application of PF2α nor TXA2 analog effect the vasodilation. Magnesium induced a concentration- and smooth muscle cell-dependent dilation in cerebral penetrating arterioles. Calcium-sensitive potassium channels of smooth muscle cells may play a key role in magnesium-induced vasodilation. Magnesium also dilated endothelium-impaired vessels as well as vessels preconstricted with spasmogenic agonists. These results provide a fundamental background for the clinical use of magnesium, especially in treatment against delayed cerebral ischemia or vasospasm following SAH.

  13. N-Hexyl-4-aminobutyl glycosides for investigating structures and biological functions of carbohydrates.

    Science.gov (United States)

    Suzuki, Katsuhiko; Tobe, Akifumi; Adachi, Shin; Daikoku, Shusaku; Hasegawa, Yasuko; Shioiri, Yuki; Kobayashi, Mariko; Kanie, Osamu

    2009-11-21

    The potential applications of N-hexyl-4-aminobutyl glycosides in the mass spectrometric investigation of glycan structure and in the investigation of glycan functions were studied. Under collision-induced dissociation (CID) conditions, sodiated glycosides carrying N-hexyl-4-aminobutyl groups effectively produced a hemiacetal species (C-ions), which is important in mass-spectrometry-based structural investigation. The usefulness of N-hexyl-4-aminobutyl glycosides in biological analysis was also confirmed by obtaining a binding constant for the binding of dipyrrometheneboron difluoride C3-labeled N-hexyl-4-aminobutyl beta-lactoside with an Erythrina cristagalli lectin, and by visualizing cellular organelles using a more hydrophobic BODIPY-labeled compound.

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

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

    Science.gov (United States)

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

    2016-12-01

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

  16. 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

    conditions. A quartz capillary cell allowed the in situ study of gas/solid reactions. Three phases were identified: Mg, MgH2 and MgO and their phase fractions were extracted by Rietveld refinement or integration of selected reflections from each phase. Dehydrogenation curves were constructed and analysed...... by the Johnson-Mehi-Avrami formalism in order to derive rate constants at different temperatures. The apparent activation energies for dehydrogenation of pure and Ni-doped magnesium hydride were E-A approximate to 300 and 250 kJ/mol, respectively. Differential scanning calorimetry gave, E-A = 270 k......J/mol for dehydrogenation of the Ni-doped sample. The relatively high activation energies are due to MgO surface layers, retarding the diffusion of hydrogen (H-2) out of MgH2/Mg. The observed difference in E-A of ca. 50 kJ/moI is likely due to the catalytic effect of Ni on the recombination of H atoms to H-2 molecules...

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-01-01

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

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

    Science.gov (United States)

    Patke, Usha

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

  20. Shear bands in magnesium alloy AZ31

    Institute of Scientific and Technical Information of China (English)

    杨平; 毛卫民; 任学平; 唐全波

    2004-01-01

    During deformation of magnesium at low temperatures, cracks always develop at shear bands. The origin of the shear bands is the {101-1} twinning in basal-oriented grains and the mobility of this type of twin boundary is rather low. The most frequent deformation mechanisms in magnesium at low temperature are basal slip and {1012} twinning, all leading to the basal texture and therefore the formation of shear bands with subsequent fracture. The investigation on the influences of initial textures and grain sizes reveals that a strong prismatic initial texture of parallels to TD and fine grains of less than 5 μm can restrict the formation and expansion of shear bands effectively and therefore improve the mechanical properties and formability of magnesium.

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

    Science.gov (United States)

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

    2016-03-01

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

  2. The developing strategy of Chinese magnesium and magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    ZUO; Tie-yong; DU; Wen-bo

    2005-01-01

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

  3. Biologic

    CERN Document Server

    Kauffman, L H

    2002-01-01

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

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

    Science.gov (United States)

    Trewyn, Brian G.

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

  5. Numerical investigation of thermal response of laser-irradiated biological tissue phantoms embedded with gold nanoshells.

    Science.gov (United States)

    Phadnis, Akshay; Kumar, Sumit; Srivastava, Atul

    2016-10-01

    The work presented in this paper focuses on numerically investigating the thermal response of gold nanoshells-embedded biological tissue phantoms with potential applications into photo-thermal therapy wherein the interest is in destroying the cancerous cells with minimum damage to the surrounding healthy cells. The tissue phantom has been irradiated with a pico-second laser. Radiative transfer equation (RTE) has been employed to model the light-tissue interaction using discrete ordinate method (DOM). For determining the temperature distribution inside the tissue phantom, the RTE has been solved in combination with a generalized non-Fourier heat conduction model namely the dual phase lag bio-heat transfer model. The numerical code comprising the coupled RTE-bio-heat transfer equation, developed as a part of the current work, has been benchmarked against the experimental as well as the numerical results available in the literature. It has been demonstrated that the temperature of the optical inhomogeneity inside the biological tissue phantom embedded with gold nanoshells is relatively higher than that of the baseline case (no nanoshells) for the same laser power and operation time. The study clearly underlines the impact of nanoshell concentration and its size on the thermal response of the biological tissue sample. The comparative study concerned with the size and concentration of nanoshells showed that 60nm nanoshells with concentration of 5×10(15)mm(-3) result into the temperature levels that are optimum for the irreversible destruction of cancer infected cells in the context of photo-thermal therapy. To the best of the knowledge of the authors, the present study is one of the first attempts to quantify the influence of gold nanoshells on the temperature distributions inside the biological tissue phantoms upon laser irradiation using the dual phase lag heat conduction model.

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

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-30

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

  8. Structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine investigated using density functional theory

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculation were adopted to study the structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine (TTPPzH2 and TTPPzMg) using B3LYP method with the 6-31G(d) basis set.A comparison of the geometrical structures,atomic charges,molecular orbitals,UV-vis spectra and infrared (IR) spectra among tetrathieno[2,3-b]porphyrazine (TTPPzH2),phthalocyanine (H2Pc) and porphyrazine (H2Pz) compounds was performed.The substituent effect of the thiophene heterocycle for electron-donating on the structures and properties of these compounds has been discussed.Compared with other atoms,the charge distribution of Cβ atoms adjacent to the sulfur atom is significantly influenced by the thiophene heterocycle substituents.The enlargement of the HOMO-LUMO gaps from H2Pc and MgPc to TTPPzH2 and TTPPzMg is at the origin of the observed blue shift of the Q band when moving from H2Pc to TTPPzH2 compounds.Special emphasis has been devoted to the strongest B bands for TTPPzH2 compounds which show red shift due to the large destabilization of the lower lying occupied orbitals compared with the corresponding B bands of H2Pc compounds.With the assistance of animated pictures produced on the basis of the normal coordinates,the significant peaks and vibration modes in the IR spectra of all the compounds were assigned and analyzed.

  9. Effects of high doses of magnesium in drinking water and voluntary wheel running on magnesium and calcium concentrations in rats.

    Science.gov (United States)

    Meludu, S C; Nishimuta, M; Aboh, N A; Okonkwo, C; Dioka, C E

    2002-12-01

    The effect of high magnesium intake in addition to supplementation and voluntary wheel activity on magnesium and calcium homeostasis was investigated in rats. Thirty-six 5-week-old male Wistar rats were divided into four groups (n = 9). Groups 2 and 4 received five hundred ppm of elemental magnesium as MgCl2 provided in drinking water. After 1 week of acclimatization and 4 weeks of supplement and/or exercise, the animals were fasted and sacrificed. It appears that magnesium supplementation as well as exercise played some significant role in the homeostatic changes of magnesium and calcium. This could be of great significance in better understanding of mineral homeostasis particularly in sports medicine.

  10. 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.

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

    Institute of Scientific and Technical Information of China (English)

    秦铁男; 马立群; 贺忠臣; 姚妍; 丁毅

    2011-01-01

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

  12. Rolling of microalloyed magnesium sheets

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-01

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

  13. [The investigation of nickel dissolution from nitinol under different extraction conditions in biological tests].

    Science.gov (United States)

    Wen, Xiantao; He, Xueying; Li, Jian; Tang, Juli; Huang, Yongfu

    2013-03-01

    The dissolution of nickel from nitinol alloy under different extraction conditions was investigated when biological tests of nitinol medical devices were carried out. It discussed the equivalence of these extraction conditions and found the best extraction conditions. In the experiment, two brands of nitinol were chosen and extracted under different extraction conditions according to GB/T 16886-12. Plasma emission spectrometer was used to analyse the concentration of nickel in extract liquid. The results show that there is no equivalence among these extraction conditions for nitinol materials. And it is suggested that (37 +/- 1) degree C, (72 +/- 2) h could be used as normal extraction condition and (70 +/- 2) degrees C, (24 +/- 2) h as accelerated extraction condition.

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

    CERN Document Server

    Bregadze, Vasil G; Tsakadze, Ketevan J

    2007-01-01

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

  15. Biological and chemical investigation of Allium cepa L. response to selenium inorganic compounds.

    Science.gov (United States)

    Michalska-Kacymirow, M; Kurek, E; Smolis, A; Wierzbicka, M; Bulska, E

    2014-06-01

    The aim of this study was to evaluate the biological and chemical response of Allium cepa L. exposed to inorganic selenium compounds. Besides the investigation of the total content of selenium as well as its chemical speciation, the Allium test was used to evaluate the growth of onion roots and mitotic activity in the roots' meristem. The total content of selenium was determined by inductively coupled plasma mass spectrometry (ICP MS). High-performance liquid chromatography (HPLC), coupled to ICP MS, was used for the selenium chemical speciation. Results indicated that A. cepa plants are able to biotransform inorganic selenium compounds into their organic derivatives, e.g., Se-methylselenocysteine from the Se(IV) inorganic precursor. Although the differences in the biotransformation of selenium are due mainly to the oxidation state of selenium, the experiment has also shown a fine effect of counter ions (H(+), Na(+), NH4 (+)) on the response of plants and on the specific metabolism of selenium.

  16. Systems Biology Investigations of Pseudomonas aeruginosa Evolution in Association with Human Airway Infections

    DEFF Research Database (Denmark)

    Pedersen, Søren Damkiær

    Most knowledge about evolutionary adaptation has been gained from experimental evolution studies, in which organisms have been allowed to evolve under simple, well-defined conditions in the laboratory. While these studies have provided novel insight into the fundamental processes of evolutionary...... environments. The model system used for these investigations has been long-term chronic airway infections in Cystic fibrosis (CF) patients caused by the opportunistic pathogen Pseudomonas aeruginosa. Using a systems biology approach, we have monitored the adaptive development of the clinically important P....... aeruginosa DK2 clone lineage during 200,000 generations of evolution in the CF airways from its entrance in the clinic in the 1970’ies until the end of 2010. Genetic analysis showed that the DK2 lineage between 1973 and 2007 accumulated mutations in a near-linear manner with an overall genomic signature...

  17. Aquatic biology in Nederlo Creek, southwestern Wisconsin. Water-resources investigations (final)

    Energy Technology Data Exchange (ETDEWEB)

    Kammerer, P.A. Jr.; Lidwin, R.A.; Mason, J.W.; Narf, R.P.

    1982-09-01

    This report presents the results of biologic investigations made during a study of hydrology and water quality in a small drainage basin in the 'Driftless Area' of southwest Wisconsin. The aquatic community is diverse and reasonably stable with little indication of environmental disturbance. Aquatic macrophyte population (dominated by Ranunculus aquatilis L., Veronica catenata Penn., and Nasturtium officinale) varies little from spring to fall. Periphytic and planktonic algae are predominantly diatoms, with the genus Achnanthes dominating both communities. The benthic invertebrate population is dominated by Trichoptera. The trout population is low and represents only a small part of the total fish population both in biomass and numbers. The wild trout population is highly dependent on spawning success; when spawning success was poor, populations the following fall were extremely low.

  18. The status of strontium in biological apatites: an XANES investigation.

    Science.gov (United States)

    Bazin, D; Daudon, M; Chappard, Ch; Rehr, J J; Thiaudière, D; Reguer, S

    2011-11-01

    Osteoporosis represents a major public health problem and increases patient morbidity through its association with fragility fractures. Among the different treatments proposed, strontium-based drugs have been shown to increase bone mass in postmenopausal osteoporosis patients and to reduce fracture risk. While the localization of Sr(2+) cations in the bone matrix has been extensively studied, little is known regarding the status of Sr(2+) cations in natural biological apatite. In this investigation the local environment of Sr(2+) cations has been investigated through XANES (X-ray absorption near-edge structure) spectroscopy in a set of pathological and physiological apatites. To assess the localization of Sr(2+) cations in these biological apatites, numerical simulations using the ab initio FEFF9 X-ray spectroscopy program have been performed. The complete set of data show that the XANES part of the absorption spectra may be used as a fingerprint to determine the localization of Sr(2+) cations versus the mineral part of calcifications. More precisely, it appears that a relationship exists between some features present in the XANES part and a Sr(2+)/Ca(2+) substitution process in site (I) of crystal apatite. Regarding the data, further experiments are needed to confirm a possible link between the relationship between the preparation mode of the calcification (cellular activity for physiological calcification and precipitation for the pathological one) and the adsorption mode of Sr(2+) cations (simple adsorption or insertion). Is it possible to draw a line between life and chemistry through the localization of Sr in apatite? The question is open for discussion. A better structural description of these physiological and pathological calcifications will help to develop specific therapies targeting the demineralization process in the case of osteoporosis.

  19. Effects of oral magnesium supplementation on inflammatory markers in middle-aged overweight women

    Directory of Open Access Journals (Sweden)

    Nazanin Moslehi

    2012-01-01

    Full Text Available Background: This study aimed to investigate whether magnesium supplementation might affect serum magnesium, high sensitive C-reactive protein (hs-CRP, plasma fibrinogen, and interleukin 6 (IL-6 levels in healthy middle-aged overweight women. The relationships, if any, between serum magnesium and the inflammatory markers were also examined cross-sectionally in the entire participants at the beginning of the study. Materials and Methods: This double-blinded, placebo-controlled, randomized trial included 74 middle-aged overweight women. Participants were randomly assigned to receive either 250 mg magnesium as magnesium oxide or placebo daily for 8 weeks. Serum magnesium, hs-CRP, fibrinogen and IL-6 concentrations were measured before and after the intervention. Results: Serum magnesium was found to be inversely correlated with hs-CRP (r s =−0.22, P=0.05 in the entire participants at baseline. Serum hs-CRP declined significantly in both groups as compared with baseline values (median change=0.8 mg/L; P Magnesium= 0.03, P Placebo 0.001. Plasma fibrinogen decreased significantly, by 9%, in the magnesium group at the end of week 8 compared to baseline (P=0.001. Mean concentration of IL-6 was significantly increased in the magnesium group comparing the baseline value(P=0.001. However hs-CRP, fibrinogen and IL-6 levels at week 8 or any changes during the study were not statistically different between the two groups. Serum magnesium showed no significant changes in any groups. Conclusions: Serum magnesium had a significant inverse correlation with hs-CRP. In the present study, magnesium as magnesium oxide, 250 mg/day, for 8 weeks did not significantly attenuate inflammatory markers in the magnesium group as compared to the placebo.

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

    Science.gov (United States)

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

    2011-12-01

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

  1. Treatment with magnesium sulphate in pre-term birth

    DEFF Research Database (Denmark)

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

    2012-01-01

    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......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...

  2. Investigating the Use of Inquiry & Web-Based Activities with Inclusive Biology Learners

    Science.gov (United States)

    Bodzin, Alec M.; Waller, Patricia L.; Edwards, Lana; Darlene Kale, Santoro

    2007-01-01

    A Web-integrated biology program is used to explore how to best assist inclusive high school students to learn biology with inquiry-based activities. Classroom adaptations and instructional strategies teachers may use to assist in promoting biology learning with inclusive learners are discussed.

  3. Investigation of resins suitable for the preparation of biological sample for 3-D electron microscopy.

    Science.gov (United States)

    Kizilyaprak, Caroline; Longo, Giovanni; Daraspe, Jean; Humbel, Bruno M

    2015-02-01

    In the last two decades, the third-dimension has become a focus of attention in electron microscopy to better understand the interactions within subcellular compartments. Initially, transmission electron tomography (TEM tomography) was introduced to image the cell volume in semi-thin sections (∼ 500 nm). With the introduction of the focused ion beam scanning electron microscope, a new tool, FIB-SEM tomography, became available to image much larger volumes. During TEM tomography and FIB-SEM tomography, the resin section is exposed to a high electron/ion dose such that the stability of the resin embedded biological sample becomes an important issue. The shrinkage of a resin section in each dimension, especially in depth, is a well-known phenomenon. To ensure the dimensional integrity of the final volume of the cell, it is important to assess the properties of the different resins and determine the formulation which has the best stability in the electron/ion beam. Here, eight different resin formulations were examined. The effects of radiation damage were evaluated after different times of TEM irradiation. To get additional information on mass-loss and the physical properties of the resins (stiffness and adhesion), the topography of the irradiated areas was analysed with atomic force microscopy (AFM). Further, the behaviour of the resins was analysed after ion milling of the surface of the sample with different ion currents. In conclusion, two resin formulations, Hard Plus and the mixture of Durcupan/Epon, emerged that were considerably less affected and reasonably stable in the electron/ion beam and thus suitable for the 3-D investigation of biological samples.

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

    Science.gov (United States)

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

    2015-04-01

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

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

    Institute of Scientific and Technical Information of China (English)

    玉泉; 周少基; 刘慧霞; 覃晓雨; 黄威威

    2013-01-01

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

  6. 21 CFR 601.50 - Confidentiality of data and information in an investigational new drug notice for a biological...

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Confidentiality of data and information in an investigational new drug notice for a biological product. 601.50 Section 601.50 Food and Drugs FOOD AND DRUG... Information § 601.50 Confidentiality of data and information in an investigational new drug notice for...

  7. Microstructure and kinetics of hot deformation WE43 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-07-01

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

  9. A system for investigation of biological effects of diagnostic ultrasound on development of zebrafish embryos.

    Science.gov (United States)

    Miller, Douglas L; Zhou, Weibin

    2013-12-01

    A system for scanning zebrafish embryos with diagnostic ultrasound was developed for research into possible biological effects during development. Two troughs for holding embryos were formed from agarose in a rectangular dish and separated by an ultrasound absorber. A 4.9 MHz linear array ultrasound probe was positioned to uniformly scan all the embryos at the bottom of one trough, with the other used for controls. Zebrafish embryos were scanned continuously from 10-24 h post fertilization (hpf) during the segmentation period and gross morphological parameters were measured at 30 hpf, including viability, length, number of visible axons, and the progression of the lateral line primordium (LLP). Our initial tests were encumbered by the thermal effects of probe self-heating, which resulted in accelerated development of the zebrafish embryos. After subsequent optimization, our test revealed a significant retardation of primary motor axons and the migration of the LLP in embryos scanned with ultrasound, which indicated a potential for nonthermal effects on neuronal development. This diagnostic ultrasound exposure system is suitable for further investigation of possible subtle bioeffects, such as perturbation of neuronal migration.

  10. An investigation of a nonlocal hyperbolic model for self-organization of biological groups.

    Science.gov (United States)

    Fetecau, Razvan C; Eftimie, Raluca

    2010-10-01

    In this article, we introduce and study a new nonlocal hyperbolic model for the formation and movement of animal aggregations. We assume that the nonlocal attractive, repulsive, and alignment interactions between individuals can influence both the speed and the turning rates of group members. We use analytical and numerical techniques to investigate the effect of these nonlocal interactions on the long-time behavior of the patterns exhibited by the model. We establish the local existence and uniqueness and show that the nonlinear hyperbolic system does not develop shock solutions (gradient blow-up). Depending on the relative magnitudes of attraction and repulsion, we show that the solutions of the model either exist globally in time or may exhibit finite-time amplitude blow-up. We illustrate numerically the various patterns displayed by the model: dispersive aggregations, finite-size groups and blow-up patterns, the latter corresponding to aggregations which may collapse to a point. The transition from finite-size to blow-up patterns is governed by the magnitude of the social interactions and the random turning rates. The presence of these types of patterns and the absence of shocks are consequences of the biologically relevant assumptions regarding the form of the speed and the turning rate functions, as well as of the kernels describing the social interactions.

  11. Experimental Fluidic Investigation of Degradation of Pico-liter Oil Droplets by Physical and Biological Processes

    Science.gov (United States)

    Jalali, Maryam; Sheng, Jian

    2016-11-01

    This study used laboratory experiments to assess degradation of crude oil by physical and biological processes including dissolution and consumption. To perform this study, we have developed a bioassay that consists of a flow chamber with a bottom glass substrate printed with an array of pico-liter oil droplets using micro-Transfer Printing. The technique allows the printing of highly homogeneous pico-liter droplet array with different dimensions and shapes that can be maintained for weeks. Since the droplets are pinned and stationary on the bottom substrate, the key processes can be evaluated by measuring the change of shape and volume using Atomic Force Microscopy. Parallel microfluidic bioassays are established at the beginning, exposed to abiotic/biotic solutions, and scarified for characterization at given time intervals for each experiment. Two processes, dissolution and consumption, are investigated. In addition, the effects of dispersant on these processes are also studied. The results show that the amount of oil degraded by bacteria accounts for almost 50% of the total volume in comparison to 25% via dissolution. Although dispersant has a subtle effect on dissolution, the effect on rates of consumption and its asymptotic behavior are substantial. Experiments involving different bacterial strains, dispersant concentration, and flow shear rate are on-going.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Thibaut Malausa

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

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

    Science.gov (United States)

    Moussavi, Gholamreza; Leili, Mostafa; Nadafi, Kazem

    2016-01-01

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

  15. Investigation of endosome and lysosome biology by ultra pH-sensitive nanoprobes.

    Science.gov (United States)

    Wang, Chensu; Zhao, Tian; Li, Yang; Huang, Gang; White, Michael A; Gao, Jinming

    2016-09-06

    Endosomes and lysosomes play a critical role in various aspects of cell physiology such as nutrient sensing, receptor recycling, protein/lipid catabolism, and cell death. In drug delivery, endosomal release of therapeutic payloads from nanocarriers is also important in achieving efficient delivery of drugs to reach their intracellular targets. Recently, we invented a library of ultra pH-sensitive (UPS) nanoprobes with exquisite fluorescence response to subtle pH changes. The UPS nanoprobes also displayed strong pH-specific buffer effect over small molecular bases with broad pH responses (e.g., chloroquine and NH4Cl). Tunable pH transitions from 7.4 to 4.0 of UPS nanoprobes cover the entire physiological pH of endocytic organelles (e.g., early and late endosomes) and lysosomes. These unique physico-chemical properties of UPS nanoprobes allowed a 'detection and perturbation' strategy for the investigation of luminal pH in cell signaling and metabolism, which introduces a nanotechnology-enabled paradigm for the biological studies of endosomes and lysosomes.

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

    Science.gov (United States)

    Cisek, Richard

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

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

    Science.gov (United States)

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

    2007-05-01

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

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

    Science.gov (United States)

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

    2003-08-01

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

  19. 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.

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

    Science.gov (United States)

    Quinn, Frances; Pegg, John; Panizzon, Debra

    2009-01-01

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

  1. 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

  2. Magnesium for Hydrogen Storage

    DEFF Research Database (Denmark)

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

    1983-01-01

    at temperatures around 600 K and above, but the reversed reaction showed somewhat slower kinetics around 600 K. At higher temperatures the opposite was found. The enthalpy and entropy change by the hydrogenation, derived from pressure-concentration isotherms, agree fairly well with those reported earlier.......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...

  3. Topologically ordered magnesium-biopolymer hybrid composite structures.

    Science.gov (United States)

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

    2015-01-01

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

  4. Alterations in magnesium and oxidative status during chronic emotional stress.

    Science.gov (United States)

    Cernak, I; Savic, V; Kotur, J; Prokic, V; Kuljic, B; Grbovic, D; Veljovic, M

    2000-03-01

    Magnesium and oxidative status were investigated in young volunteers exposed to chronic stress (political intolerance, awareness of potential military attacks, permanent stand-by duty and reduced holidays more than 10 years) or subchronic stress consisting of everyday mortal danger in military actions lasting more than 3 months. Significant decreases in plasma ionized Mg2+, total Mg and ionized Ca2+ concentrations were found in both groups. Similarly, both study groups exhibited oxidative stress as assessed by increased plasma superoxide anions and malondialdehyde and modified antioxidant defense. There were no significant differences between the two stress groups. A negative correlation between magnesium balance and oxidative stress was observed suggesting that the same etiological factor (chronic stress) initiate decreases in both free and total magnesium concentrations and simultaneously increase oxidative stress intensity. These findings support the need for magnesium supplementation with antioxidant vitamins for people living in conditions of chronic stress.

  5. 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.

  6. The status of strontium in biological apatites: an XANES/EXAFS investigation.

    Science.gov (United States)

    Bazin, Dominique; Dessombz, Arnaud; Nguyen, Christelle; Ea, Hang Korng; Lioté, Frédéric; Rehr, John; Chappard, Christine; Rouzière, Stephan; Thiaudière, Dominique; Reguer, Solen; Daudon, Michel

    2014-01-01

    Osteoporosis represents a major public health problem through its association with fragility fractures. The public health burden of osteoporotic fractures will rise in future generations, due in part to an increase in life expectancy. Strontium-based drugs have been shown to increase bone mass in postmenopausal osteoporosis patients and to reduce fracture risk but the molecular mechanisms of the action of these Sr-based drugs are not totally elucidated. The local environment of Sr(2+) cations in biological apatites present in pathological and physiological calcifications in patients without such Sr-based drugs has been assessed. In this investigation, X-ray absorption spectra have been collected for 17 pathological and physiological calcifications. These experimental data have been combined with a set of numerical simulations using the ab initio FEFF9 X-ray spectroscopy program which takes into account possible distortion and Ca/Sr substitution in the environment of the Sr(2+) cations. For selected samples, Fourier transforms of the EXAFS modulations have been performed. The complete set of experimental data collected on 17 samples indicates that there is no relationship between the nature of the calcification (physiological and pathological) and the adsorption mode of Sr(2+) cations (simple adsorption or insertion). Such structural considerations have medical implications. Pathological and physiological calcifications correspond to two very different preparation procedures but are associated with the same localization of Sr(2+) versus apatite crystals. Based on this study, it seems that for supplementation of Sr at low concentration, Sr(2+) cations will be localized into the apatite network.

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

    Science.gov (United States)

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

    2014-11-01

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

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

    Science.gov (United States)

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

    2014-12-01

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

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

    OpenAIRE

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

    2010-01-01

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

  10. Investigating the status of biological stimuli as objects of attention in multiple object tracking.

    Directory of Open Access Journals (Sweden)

    Lee H de-Wit

    Full Text Available BACKGROUND: Humans are able to track multiple simultaneously moving objects. A number of factors have been identified that can influence the ease with which objects can be attended and tracked. Here, we explored the possibility that object tracking abilities may be specialized for tracking biological targets such as people. METHODOLOGY/PRINCIPAL FINDINGS: We used the Multiple Object Tracking (MOT paradigm to explore whether the high-level biological status of the targets affects the efficiency of attentional selection and tracking. In Experiment 1, we assessed the tracking of point-light biological motion figures. As controls, we used either the same stimuli or point-light letters, presented in upright, inverted or scrambled configurations. While scrambling significantly affected performance for both letters and point-light figures, there was an effect of inversion restricted to biological motion, inverted figures being harder to track. In Experiment 2, we found that tracking performance was equivalent for natural point-light walkers and 'moon-walkers', whose implied direction was incongruent with their actual direction of motion. In Experiment 3, we found higher tracking accuracy for inverted faces compared with upright faces. Thus, there was a double dissociation between inversion effects for biological motion and faces, with no inversion effect for our non-biological stimuli (letters, houses. CONCLUSIONS/SIGNIFICANCE: MOT is sensitive to some, but not all naturalistic aspects of biological stimuli. There does not appear to be a highly specialized role for tracking people. However, MOT appears constrained by principles of object segmentation and grouping, where effectively grouped, coherent objects, but not necessarily biological objects, are tracked most successfully.

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

    Science.gov (United States)

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

    2005-05-01

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

  12. 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...

  13. 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...

  14. 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...

  15. 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).

  16. 21 CFR 184.1428 - Magnesium hydroxide.

    Science.gov (United States)

    2010-04-01

    ... hydration of reactive grades of magnesium oxide. (b) The ingredient meets the specifications of the Food... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium hydroxide. 184.1428 Section 184.1428 Food... Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2,...

  17. 21 CFR 184.1426 - Magnesium chloride.

    Science.gov (United States)

    2010-04-01

    ... mineral bischofite. It is prepared by dissolving magnesium oxide, hydroxide, or carbonate in aqueous... 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,...

  18. Magnesium Oxide Induced Metabolic Alkalosis in Cattle

    OpenAIRE

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

    1983-01-01

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

  19. 21 CFR 184.1434 - Magnesium phosphate.

    Science.gov (United States)

    2010-04-01

    ... solution of magnesite with phosphoric acid. (b) Magnesium phosphate, dibasic, meets the specifications of... 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...

  20. Investigation of specificity ensuring of quality of biological medicinal products on example of drugs Cortexin and Retinalamin

    Directory of Open Access Journals (Sweden)

    N. O. Vetiutneva

    2013-06-01

    consists of the following stages: preparing of the solution for bottling, sterilizing filtration, washing and sterilizing of the bottles, aseptic filling, freeze drying and plugging, seaming, continuous monitoring in bulk. After getting the quality certificate and declaration of conformity products are transferred to the storage place for finished products. The specificity of differences between biological medical products and synthetic medicines was investigated. Stages of ensuring of the quality of biological medicinal products with considering of particular qualities of the critical points were considered - the special conditions in the manufacturing process, temperature monitoring, systems and procedures of ensuring in quality during transportation, storage. The main stages of ensuring of quality were studied on the example of original drugs Cortexin and Retinalamin in the chain from production to sale.

  1. Investigation about thermal conductivities of La{sub 2}Ce{sub 2}O{sub 7} doped with calcium or magnesium for thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hongsong, E-mail: zhs761128@163.com [Department of Mechanical Engineering, Henan Institute of Engineering, Zhengzhou 450007 (China); Yuan Wei [Department of Materials and Chemistry, Henan Institute of Engineering, Zhengzhou 450007 (China); Li Gang [Department of Mechanical Engineering, Henan Institute of Engineering, Zhengzhou 450007 (China); Chen Xiaoge [Department of Construction Engineering, Henan Institute of Engineering, Zhengzhou 450007 (China); Wang Xinli [Department of Mechanical Engineering, Henan Institute of Engineering, Zhengzhou 450007 (China)

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer These ceramic materials with fluorite structure were synthesized. Black-Right-Pointing-Pointer Oxygen vacancies lead to their lower thermal conductivities. Black-Right-Pointing-Pointer These ceramics can be explored as novel candidate ceramic materials for TBCs. - Abstract: The La{sub 2}Ce{sub 2}O{sub 7} powders doped with Ca and Mg were synthesized by sol-gel method in this paper and their dense bulk samples were also prepared by pressure-less sintering at 1600 Degree-Sign C for 10 h. Their phase compositions, microstructures and thermal conductivities were investigated, respectively. XRD results reveal that single-phase (La{sub 0.95}Ca{sub 0.05}){sub 2}Ce{sub 2}O{sub 6.95} and (La{sub 0.95}Mg{sub 0.05}){sub 2}Ce{sub 2}O{sub 6.95} ceramics with fluorite structure are successfully synthesized. SEM and EDS results show that their microstructures are very dense and no other unreacted oxides or interphases exist in the interfaces between grains. Their thermal conductivities are lower than that of YSZ, which can be attributed to the phonon scattering caused by vacancies in their crystal lattices. The larger differences in atomic weight and ionic radius between Mg and La lead to the lower thermal conductivity of (La{sub 0.95}Mg{sub 0.05}){sub 2}Ce{sub 2}O{sub 6.95} than that of (La{sub 0.95}Ca{sub 0.05}){sub 2}Ce{sub 2}O{sub 6.95}. The synthesized rare earth cerium oxides have potentials to be used as novel candidate materials for thermal barrier coatings in the future.

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

    Science.gov (United States)

    Blaine, Judith; Chonchol, Michel; Levi, Moshe

    2015-07-01

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

  3. 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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

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

  5. Confession of a Magnesium Battery.

    Science.gov (United States)

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

    2015-09-17

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-01

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

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

    CERN Document Server

    Likhtenshtein, Gertz

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-10-01

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

  9. Investigating Membranes: Using Artificial Membranes to Convey Chemistry and Biology Concepts

    Science.gov (United States)

    Zrelak, Yoshi; McCallister, Gary

    2009-01-01

    While not organic in nature, quick-"growing" artificial membranes can be a profound visual aid when teaching students about cellular processes and the chemical nature of membranes. Students are often intrigued when they see biological and chemical concepts come to life before their eyes. In this article, the authors share their approach to growing…

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

    Science.gov (United States)

    Ates, Hüseyin; Saylan, Asli

    2015-01-01

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

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

    Science.gov (United States)

    Billingsley, James; Carlson, Kimberly A.

    2010-01-01

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

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

    Science.gov (United States)

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

    2016-03-23

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

  13. Investigating Student Interactions within a Problem-Based Learning Environment in Biology.

    Science.gov (United States)

    Guerrera, Claudia P.; Lajoie, Susanne P.

    This aim of this study was to analyze the content of students' verbal interactions within a problem-based learning context in biology. This was achieved through the qualitative analysis of the verbal protocols of three groups of two clases of ninth-grade female students (average/high ability, high/high ability, and average/average ability). The…

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

    Science.gov (United States)

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

    2013-01-01

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

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

    DEFF Research Database (Denmark)

    Kadarmideen, Haja; Watson-Haigh, Nathan S.

    2012-01-01

    Gene co-expression networks (GCN), built using high-throughput gene expression data are fundamental aspects of systems biology. The main aims of this study were to compare two popular approaches to building and analysing GCN. We use real ovine microarray transcriptomics datasets representing four...

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

    Science.gov (United States)

    Marchette, Frances Lenora

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

  17. Investigation of sintering kinetics of magnesium titanate

    Directory of Open Access Journals (Sweden)

    Petrović V.V.

    2013-01-01

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

  18. 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.

  19. Cement from magnesium substituted hydroxyapatite.

    Science.gov (United States)

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

    2005-05-01

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

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Science.gov (United States)

    Chang, Bernard P; Lenzenweger, Mark F

    2004-01-01

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

  2. New method for investigation of cells and other biological objects in analytical cytology

    Science.gov (United States)

    Bilyi, Olexander I.; Getman, Vasyl B.; Kostyukevych, Sergey A.

    2001-05-01

    New method and instrument intended for checking the content of biology particles in dimension band 0.1-10.0 mkm in water flow is described in this report. The instrument measures the intensity of light scattered by the particles suspended in liquid flow when they are crossing the laser beam. The results of studying light scattered by platelet and bacterium's such a Pseudomonas aeruginosa, Escherichia coli, Micrococcus lutteus in such a liquid mediums as physiological solution and glucose solution are described.

  3. 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 ...

  4. 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

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

    Directory of Open Access Journals (Sweden)

    Pinar Terzioglu

    2012-11-01

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

  6. Magnesium used in bioabsorbable stents controls smooth muscle cell proliferation and stimulates endothelial cells in vitro.

    Science.gov (United States)

    Sternberg, Katrin; Gratz, Matthias; Koeck, Kathleen; Mostertz, Joerg; Begunk, Robert; Loebler, Marian; Semmling, Beatrice; Seidlitz, Anne; Hildebrandt, Petra; Homuth, Georg; Grabow, Niels; Tuemmler, Conny; Weitschies, Werner; Schmitz, Klaus-Peter; Kroemer, Heyo K

    2012-01-01

    Magnesium-based bioabsorbable cardiovascular stents have been developed to overcome limitations of permanent metallic stents, such as late stent thrombosis. During stent degradation, endothelial and smooth muscle cells will be exposed to locally high magnesium concentrations with yet unknown physiological consequences. Here, we investigated the effects of elevated magnesium concentrations on human coronary artery endothelial and smooth muscle cell (HCAEC, HCASMC) growth and gene expression. In the course of 24 h after incubation with magnesium chloride solutions (1 or 10 mM) intracellular magnesium level in HCASMC raised from 0.55 ± 0.25 mM (1 mM) to 1.38 ± 0.95 mM (10 mM), while no increase was detected in HCAEC. Accordingly, a DNA microarray-based study identified 69 magnesium regulated transcripts in HCAEC, but 2172 magnesium regulated transcripts in HCASMC. Notably, a significant regulation of various growth factors and extracellular matrix components was observed. In contrast, viability and proliferation of HCAEC were increased at concentrations of up to 25 mM magnesium chloride, while in HCASMC viability and proliferation appeared to be unaffected. Taken together, our data indicate that magnesium halts smooth muscle cell proliferation and stimulates endothelial cell proliferation, which might translate into a beneficial effect in the setting of stent associated vascular injury.

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  8. Magnesium ferrite nanoparticles: a rapid gas sensor for alcohol

    Science.gov (United States)

    Godbole, Rhushikesh; Rao, Pratibha; Bhagwat, Sunita

    2017-02-01

    Highly porous spinel MgFe2O4 nanoparticles with a high specific surface area have been successfully synthesized by a sintering free auto-combustion technique and characterized for their structural and surface morphological properties using XRD, BET, TEM and SEM techniques. Their sensing properties to alcohol vapors viz. ethanol and methanol were investigated. The site occupation of metal ions was investigated by VSM. The as-synthesized sample shows the formation of sponge-like porous material which is necessary for gas adsorption. The gas sensing characteristics were obtained by measuring the gas response as a function of operating temperature, concentration of the gas, and the response-recovery time. The response of magnesium ferrite to ethanol and methanol vapors was compared and it was revealed that magnesium ferrite is more sensitive and selective to ethanol vapor. The sensor operates at a substantially low vapor concentration of about 1 ppm of alcohol vapors, exhibits fantastic response reproducibility, long term reliability and a very fast response and recovery property. Thus the present study explored the possibility of making rapidly responding alcohol vapor sensor based on magnesium ferrite. The sensing mechanism has been discussed in co-relation with magnetic and morphological properties. The role of occupancy of Mg2+ ions in magnesium ferrite on its gas sensing properties has also been studied and is found to influence the response of magnesium ferrite ethanol sensor.

  9. The prospects of biodegradable magnesium-based alloys in osteosynthesis

    Directory of Open Access Journals (Sweden)

    V. N. Chorny

    2013-12-01

    Full Text Available In the analytical review of the literature the main stages of development of biodegradable magnesium alloys in surgery and traumatology were discussed. The analysis revealed the main problems: there is no way to control the speed of the biological resorption alloys, the effects of products of magnesium degradation on the tissues and the organism in general are not studied, there is no information on the characteristics of the regeneration of bone tissue when implanted magnesium implanted magnesium alloys Materials for osteosynthesis with metal clamps made of steel X18H9T are used in 25,0-52,2% of cases, the corrosion of fasteners reaches 18-21%. Corrosion of the metal clips leads to the increase of the concentration of iron, chromium, nickel and titanium in the surrounding tissue. Electrochemical processes in metallic implants occurs due to their structural and chemical inhomogeneous. The microstructure of stainless steel is presented by differently oriented grains. Therefore, the question remains relevant to finding biodegradable materials suitable for implants for osteosynthesis, which could be completely metabolized by the organism, without causing of the pathological effects on the surrounding tissue and the body. The property of magnesium metal dissolved in the tissues of a living organism is known since the 19th century. Payr suggested the use of magnesium metal needles for the treatment of angiomas, in order to achieve thrombosis surrounding the tumor. In 1937 Lambotte made a post in the French Surgical Academy on the application of the osteosynthesis of the shin bone clamps with alloy Dow-metal (magnesium - 92% Aluminum - 8% + traces of manganese, made in the form of loops and screws. In 1938, Earl D. Mc.Braid and published their positive experience with plates and screws made of material similar in composition to the Dow-metal for osteosynthesis of fractures of the arm and forearm bones. Magnesium alloys may be used as a material for

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

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, R.M.

    1994-10-01

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

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

    Science.gov (United States)

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

    1990-01-01

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

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

    Directory of Open Access Journals (Sweden)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2014-12-10

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

  14. Calcium dependent magnesium uptake in myocardium.

    Science.gov (United States)

    Bianchi, C P; Liu, D

    1993-01-01

    The frog myocardium maintains magnesium content at a steady state level when stimulated at 0.4Hz while being perfused with Ringer's solution containing 1 x 10(-3) M Ca2+ and 5 x 10(-7) M magnesium. When calcium is removed 43% of tissue magnesium is lost within 30 seconds or 12 beats. Restoration of calcium to the perfusion solution causes reaccumulation of magnesium from a solution containing 5 x 10(-7) M magnesium. The reaccumulation of magnesium indicates a highly selective transport system for magnesium which is dependent upon the presence of calcium. Calcium appears to reduce the leak of magnesium from the myocardium and enhances the transport of magnesium into the myocardial cell. Intracellular magnesium is a necessary cofactor for hundreds of enzymes, and is essential for protein synthesis and as an extracellular divalent cation helps to stabilize excitable membranes in conjunction with calcium. The concentration of ionized magnesium in the sarcoplasm of myocardial muscle has an average value of 1.45 mM +/- 1.37 (standard deviation), N = 19) with a range of 0.5 to 3.6 mM (1). The heart with its numerous mitochondria and high enzymatic activity is vulnerable to myocardial damage due to magnesium loss. The isolated frog ventricle conserves intracellular magnesium when perfused with Ringer's solution containing no added magnesium and maintains function for hours. The ability to conserve magnesium suggests a low permeability of the sarcolemma to magnesium and an extremely efficient inward transport system. Removal of calcium as well as magnesium from the perfusion solution causes a rapid loss of tension in the electrically driven frog ventricle (0.4) Hz.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Interface chemistry and molecular bonding of functional ethoxysilane-based self-assembled monolayers on magnesium surfaces.

    Science.gov (United States)

    Killian, Manuela S; Seiler, Steffen; Wagener, Victoria; Hahn, Robert; Ebensperger, Christina; Meyer, Bernd; Schmuki, Patrik

    2015-05-06

    The modification of magnesium implants with functional organic molecules is important for increasing the biological acceptance and for reducing the corrosion rate of the implant. In this work, we evaluated by a combined experimental and theoretical approach the adsorption strength and geometry of a functional self-assembled monolayer (SAM) of hydrolyzed (3-aminopropyl)triethoxysilane (APTES) molecules on a model magnesium implant surface. In time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS), only a minor amount of reverse attachment was observed. Substrate-O-Si signals could be detected, as well as other characteristic APTES fragments. The stability of the SAM upon heating in UHV was investigated additionally. Density-functional theory (DFT) calculations were used to explore the preferred binding mode and the most favorable binding configuration of the hydrolyzed APTES molecules on the hydroxylated magnesium substrate. Attachment of the molecules via hydrogen bonding or covalent bond formation via single or multiple condensation reactions were considered. The impact of the experimental conditions and the water concentration in the solvent on the thermodynamic stability of possible APTES binding modes is analyzed as a function of the water chemical potential of the environment. Finally, the influence of van der Waals contributions to the adsorption energy will be discussed.

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

    CERN Document Server

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

    2012-01-01

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

  17. Investigation of biological reactor designs for treatment of methanol and thiodiglycol waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Sines, B.J.; Teather, E.W.; Weigand, W.A. (Univ. of Maryland, College Park, MD (United States)); Harvey, S.P. (Army Edgewood, Aberdeen Proving Ground, MD (United States))

    Biological reactor designs for the degradation of the toxic compounds methanol and thiodiglycol are compared to determine the smallest volume. Both compounds exhibit substrate-inhibited cell growth behavior. Design equations were used to simulate a continuous stirred tanks in series, and an optimized repeated fed-batch reactor. Thiodiglycol is the primary hydrolysis product of sulfur mustard (2,2[prime]-dichlorodiethyl sulfide), commonly referred to as [open quotes]mustard gas[close quotes]. Experimental data for the growth of Alcaligenes xylosoxidans xylosoxidans (SH42) on thiodiglycol was fit by an Andrews type inhibition equation, while the data and model for the growth of methanol was taken from the literature. The simulation results indicate that the repeated fed-batch reactor leads to significant volume reduction compared to the other two reactor configurations. 11 refs., 7 figs., 7 tabs.

  18. Investigating the spectrum of biological activity of ring-substituted salicylanilides and carbamoylphenylcarbamates.

    Science.gov (United States)

    Otevrel, Jan; Mandelova, Zuzana; Pesko, Matus; Guo, Jiahui; Kralova, Katarina; Sersen, Frantisek; Vejsova, Marcela; Kalinowski, Danuta S; Kovacevic, Zaklina; Coffey, Aidan; Csollei, Jozef; Richardson, Des R; Jampilek, Josef

    2010-11-10

    In this study, a series of twelve ring-substituted salicylanilides and carbamoylphenylcarbamates were prepared and characterized. The compounds were analyzed using RP-HPLC to determine lipophilicity. They were tested for their activity related to the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Moreover, their site of action in the photosynthetic apparatus was determined. Primary in vitro screening of the synthesized compounds was also performed against mycobacterial, bacterial and fungal strains. Several compounds showed biological activity comparable with or higher than the standards 3-(3,4-dichlorophenyl)-1,1-dimethylurea, isoniazid, penicillin G, ciprofloxacin or fluconazole. The most active compounds showed minimal anti-proliferative activity against human cells in culture, indicating they would have low cytotoxicity. For all compounds, the relationships between lipophilicity and the chemical structure are discussed.

  19. Investigating the Spectrum of Biological Activity of Ring-Substituted Salicylanilides and Carbamoylphenylcarbamates

    Directory of Open Access Journals (Sweden)

    Josef Jampilek

    2010-11-01

    Full Text Available In this study, a series of twelve ring-substituted salicylanilides and carbamoylphenylcarbamates were prepared and characterized. The compounds were analyzed using RP-HPLC to determine lipophilicity. They were tested for their activity related to the inhibition of photosynthetic electron transport (PET in spinach (Spinacia oleracea L. chloroplasts. Moreover, their site of action in the photosynthetic apparatus was determined. Primary in vitro screening of the synthesized compounds was also performed against mycobacterial, bacterial and fungal strains. Several compounds showed biological activity comparable with or higher than the standards 3-(3,4-dichlorophenyl-1,1-dimethylurea, isoniazid, penicillin G, ciprofloxacin or fluconazole. The most active compounds showed minimal anti-proliferative activity against human cells in culture, indicating they would have low cytotoxicity. For all compounds, the relationships between lipophilicity and the chemical structure are discussed.

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

    Science.gov (United States)

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

    2016-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-22

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

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

    Science.gov (United States)

    Zhu, Shengfa; Xu, Li; Huang, Nan

    2009-04-01

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

  3. Application of Biologically-Based Lumping To Investigate the Toxicological Interactions of a Complex Gasoline Mixture

    Science.gov (United States)

    People are often exposed to complex mixtures of environmental chemicals such as gasoline, tobacco smoke, water contaminants, or food additives. However, investigators have often considered complex mixtures as one lumped entity. Valuable information can be obtained from these exp...

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2016-05-25

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

  6. 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.

  7. 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...

  8. [Magnesium as a food supplement].

    Science.gov (United States)

    Haber, Paul

    2004-05-01

    Magnesium is a Cofactor in all enzymes transfering phosphate. It is therefore necessary for the energymetabolism and for many synthesis, i.e. DNA and RNA. Mg is one of the most widespread elements of the earthcrust and is found in many nutritients. Nevertheless the daily intake in the western countries is often under the recommended level, due to the western life stile. Regular alcohol intake lessens the resorption and regular sport enhances the excretion via the sweat. Especially in elderly people this can lead to a lack of Magnesium. This may promote muscular cramps and weakness, cardiac arrhythmias, hypertension or bronchial hyperreactivity. It seems to be reasonable to recommend liberally a oral supplementation with magnesium.

  9. Porous magnesium/PLGA composite scaffolds for enhanced bone regeneration following tooth extraction.

    Science.gov (United States)

    Brown, Andrew; Zaky, Samer; Ray, Herbert; Sfeir, Charles

    2015-01-01

    Sixty percent of implant-supported dental prostheses require bone grafting to enhance bone quantity and quality prior to implant placement. We have developed a metallic magnesium particle/PLGA composite scaffold to overcome the limitations of currently used dental bone grafting materials. This is the first report of porous metallic magnesium/PLGA scaffolds synthesized using a solvent casting, salt leaching method. We found that incorporation of varying amounts of magnesium into the PLGA scaffolds increased the compressive strength and modulus, as well as provided a porous structure suitable for cell infiltration, as measured by mercury intrusion porosimetry. Additionally, combining basic-degrading magnesium with acidic-degrading PLGA led to an overall pH buffering effect and long-term release of magnesium over the course of a 10-week degradation assay, as measured with inductively coupled plasma-atomic emission spectroscopy. Using an indirect proliferation assay adapted from ISO 10993:5, it was found that extracts of medium from degrading magnesium/PLGA scaffolds increased bone marrow stromal cell proliferation in vitro, a phenomenon observed by other groups investigating magnesium's impact on cells. Finally, magnesium/PLGA scaffold biocompatibility was assessed in a canine socket preservation model. Micro-computed tomography and histological analysis showed the magnesium/PLGA scaffolds to be safer and more effective at preserving bone height than empty controls. Three-dimensional magnesium/PLGA composite scaffolds show promise for dental socket preservation and also, potentially, orthopedic bone regeneration. These scaffolds could decrease inflammation observed with clinically used PLGA devices, as well as enhance osteogenesis, as observed with previously studied magnesium devices.

  10. Structure evolution of AZ61 magnesium alloy in SIMA process

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  13. Fretting wear behavior of AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    CHEN An-hua; HUANG Wei-jiu; LI Zhao-feng

    2006-01-01

    The fretting behaviour of the AZ91D magnesium alloy was investigated. The influence of the number of cycles, normal load (contact pressure) and the amplitude of slip on the fretting behavior of the material were focused. Fretting tests were performed under various running conditions with regard to normal load levels and slip amplitudes. The friction coefficient between the surfaces at the fretting junction was continuously recorded. The fretting damage on the magnesium specimens was studied by SEM. The results show that the wear volume increases with the increase of slip amplitude, and linearly increases with the increase of normal load in the mixed and gross slip regime, but the normal load has no obvious effect on the wear volume in the partial slip regime. The predominant fretting wear mechanism of magnesium alloy in the slip regime is the oxidation wear, delaminated wear and abrasive wear.

  14. The determination of ultrafiltrable calcium and magnesium in serum.

    Science.gov (United States)

    Danielson, B G; Pallin, E; Sohtell, M

    1982-01-01

    Ultrafiltrate of human serum was investigated in order to evaluate the serum content of calcium and magnesium. The acid and base concentrations and pH of the serum was altered through titration with HCl- or NaOH-solutions. The Pco2 was varied in the titrated serum using different carbon dioxide tensions. This was performed when serum was filtered in a recycling system. It is shown that the analysis of calcium and magnesium have to be done under anaerobic conditions or at standardized pH and Pco2 situations, as the concentrations vary with both pH and Pco2. The concentration ratio between ultrafiltrate and serum for calcium and magnesium was found to be 0.56 and 0.74 respectively at pH=7.41 and Pco2=40 mmHg.

  15. MICROSTRUCTURAL STUDIES OF FRICTION STIR WELDED AZ31 MAGNESIUM ALLOY

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    冯东福; 朱志安; 卢亦成

    2004-01-01

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

  17. 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)....

  18. 21 CFR 201.71 - Magnesium labeling.

    Science.gov (United States)

    2010-04-01

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

  19. 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...

  20. 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....

  1. Zonder magnesium zouden planten niet groen zijn

    NARCIS (Netherlands)

    Heuvelink, E.; Kierkels, T.

    2007-01-01

    Magnesium is het centrale element in het molecuul van het bladgroen. Bij een gebrek kleuren daarom de bladeren geel tussen de nerven. Zware metalen kunnen de plaats van magnesium in het bladgroen innemen. De plant kan dan niet meer assimileren. Magnesium is verder belangrijk bij heel veel processen

  2. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-01

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

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

    Science.gov (United States)

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

    2016-04-21

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

  5. Intravenous magnesium for acute asthma?

    Science.gov (United States)

    2003-10-01

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

  6. 75 FR 59935 - Investigational New Drug Safety Reporting Requirements for Human Drug and Biological Products and...

    Science.gov (United States)

    2010-09-29

    ... the developing safety profile of the drug, expedite FDA's review of critical safety information... will minimize reports that do not contribute to FDA's understanding of the developing safety profile of...., hepatic necrosis would be considered unexpected where the investigator brochure includes elevated...

  7. Influence of HEPES buffer on the local pH and formation of surface layer during in vitro degradation tests of magnesium in DMEM

    OpenAIRE

    Naddaf Dezfuli, S.; Zhigang Huan; Mol, J.M.C.; Leeflang, M. A.; Jiang Chang; Jie Zhou

    2014-01-01

    The human body is a buffered environment where pH is effectively maintained. HEPES is a biological buffer often used to mimic the buffering activity of the body in in vitro studies on the degradation behavior of magnesium. However, the influence of HEPES on the degradation behavior of magnesium in the DMEM pseudo-physiological solution has not yet been determined. The research aimed at elucidating the degradation mechanisms of magnesium in DMEM with and without HEPES. The morphologies and com...

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

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

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

  9. 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

  10. Investigating Flipped Learning: Student Self-Regulated Learning, Perceptions, and Achievement in an Introductory Biology Course

    Science.gov (United States)

    Sletten, Sarah Rae

    2017-01-01

    In flipped classrooms, lectures, which are normally delivered in-class, are assigned as homework in the form of videos, and assignments that were traditionally assigned as homework, are done as learning activities in class. It was hypothesized that the effectiveness of the flipped model hinges on a student's desire and ability to adopt a self-directed learning style. The purpose of this study was twofold; it aimed at examining the relationship between two variables—students' perceptions of the flipped model and their self-regulated learning (SRL) behaviors—and the impact that these variables have on achievement in a flipped class. For the study, 76 participants from a flipped introductory biology course were asked about their SRL strategy use and perceptions of the flipped model. SRL strategy use was measured using a modified version of the Motivated Strategies for Learning Questionnaire (MSLQ; Wolters et al. 2005), while the flipped perceptions survey was newly derived. Student letter grades were collected as a measure of achievement. Through regression analysis, it was found that students' perceptions of the flipped model positively predict students' use of several types of SRL strategies. However, the data did not indicate a relationship between student perceptions and achievement, neither directly nor indirectly, through SRL strategy use. Results suggest that flipped classrooms demonstrate their successes in the active learning sessions through constructivist teaching methods. Video lectures hold an important role in flipped classes, however, students may need to practice SRL skills to become more self-directed and effectively learn from them.

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

    Science.gov (United States)

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

    2009-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Blockhuys, S; Vanhoecke, B; Bracke, M [Laboratory Experimental Cancer Research, Ghent University Hospital, De Pintelaan 185, B-9000 Gent (Belgium); Paelinck, L; De Wagter, C [Department of Radiotherapy, Ghent University Hospital, De Pintelaan 185, B-9000 Gent (Belgium)], E-mail: Stephanie.Blockhuys@ugent.be

    2009-03-21

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

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

  14. 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.

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

    Science.gov (United States)

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

    2016-08-01

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

  16. 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.

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

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

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

    Science.gov (United States)

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

    2011-01-01

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

  19. Numerical investigation of the dynamics of nanoparticle systems in biological processes of plant nutrition

    Science.gov (United States)

    Vakhrouchev, Alexandre V.; Golubchikov, Valery B.

    2007-03-01

    A complex mathematical model of processes of plant nutrition from a special regulated gas medium containing nanoparticles of basic macro- and microelements is formulated. The variation of the number of nanoparticles and the variation of the total nanoparticle volume with time, which form during the cooling process of the initial gas mixture, were investigated. The calculations of the structures, compositions and shapes of nanoparticles and the movement of nanoparticles were carried out.

  20. Isolation of flavonoids from the heartwood and resin of Prunus avium and some preliminary biological investigations.

    Science.gov (United States)

    McNulty, James; Nair, Jerald J; Bollareddy, Endreddy; Keskar, Kunal; Thorat, Amol; Crankshaw, Denis J; Holloway, Alison C; Khan, Ghaznia; Wright, Gerard D; Ejim, Linda

    2009-12-01

    An investigation of the constituents in heartwood and resin of Prunus avium is reported. A mini-library of structurally diverse flavanones and flavones was screened for human cytochrome P450 1A1, 3A4 and 19 (aromatase) inhibition, and for antifungal activity against a panel of pathogenic fungi. The defensive role of these natural plant flavonoids as antifungal phytoalexins and phytoanticipins is discussed.

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

    Science.gov (United States)

    Iaglov, V V; Iaglova, N V

    2012-01-01

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

  2. Biological investigations of marine farms. Final report, July 1, 1976-December 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    Activities of the marine farm project from 1976 to 1979 are described. The group was concerned with biomass production. Problems such as species selection, optimal plant nutrition, and maintaining a crop at sea under simulated oceanic conditions were addressed. Overall objective of the project was to investigate feasibility of biomass production in the oceanic environment, as an alternative energy source. Project support from the gas industry caused our primary focus to be directed towards methane production.

  3. Magnesium ion-conducting gel polymer electrolytes dispersed with nanosized magnesium oxide

    Science.gov (United States)

    Pandey, G. P.; Agrawal, R. C.; Hashmi, S. A.

    Experimental investigations are performed on novel magnesium ion-conducting gel polymer electrolyte nanocomposites based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), dispersed with nanosized magnesium oxide (MgO) particles. The nanocomposite materials are in the form of free-standing films. Various physical and electrochemical analyses demonstrate promising characteristics of these films, suitable as electrolytes in rechargeable magnesium batteries. The optimized material with 3 wt.% MgO offers a maximum electrical conductivity of ∼8 × 10 -3 S cm -1 at room temperature (∼25 °C) with good thermal and electrochemical stabilities. The ion/filler-polymer interactions and possible conformational changes in host polymer PVdF-HFP due to the liquid electrolyte entrapment and dispersion of nanosized MgO are examined by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscopic (SEM) methods. The Mg 2+ ion conduction in the gel film is confirmed from the cyclic voltammetry, impedance spectroscopy and transport number measurements. The Mg 2+ ion transport number (t +) is enhanced substantially and found to have a maximum of ∼0.44 for the addition of 10 wt.% MgO nanoparticles. The enhancement in t + is explained on the basis of the formation of space-charge regions due to the presence of MgO:Mg 2+-like species, that supports Mg 2+ ion motion.

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  5. Iron Supplements and Magnesium Peroxide: An Example of a Hazardous Combination in Self-Medication.

    Science.gov (United States)

    Vrolijk, Misha F; Opperhuizen, Antoon; Jansen, Eugène H J M; Bast, Aalt; Haenen, Guido R M M

    2016-10-01

    The use of self-medication, which includes dietary supplements and over-the-counter drugs, is still on the rise, while safety issues are not well addressed yet. This especially holds for combinations. For example, iron supplements and magnesium peroxide both produce adverse effects via the formation of reactive oxygen species (ROS). This prompted us to investigate the effect of the combination of three different iron supplements with magnesium peroxide on ROS formation. Hydroxyl radical formation by the three iron supplements either combined with magnesium peroxide or alone was determined by performing a deoxyribose assay. Free iron content of iron supplements was determined using ferrozine assay. To determine hydrogen peroxide formation by magnesium peroxide, a ferrous thiocyanate assay was performed. Finally, electron spin resonance spectroscopy (ESR) was performed to confirm the formation of hydroxyl radicals. Our results show that magnesium peroxide induces the formation of hydrogen peroxide. All three iron supplements induced the formation of the extremely reactive hydroxyl radical, although the amount of radicals formed by the different supplements differed. It was shown that combining iron supplements with magnesium peroxide increases radical formation. The formation of hydroxyl radicals after the combination was confirmed with ESR. All three iron supplements contained labile iron and induced the formation of hydroxyl radicals. Additionally, magnesium peroxide in water yields hydrogen peroxide, which is converted into hydroxyl radicals by iron. Hence, iron supplements and magnesium peroxide is a hazardous combination and exemplifies that more attention should be given to combinations of products used in self-medication.

  6. Synthesis of Environmentally Friendly Magnesium Linoleate Detergent

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Xiao-hong LIU; Fu-cheng LIN

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Witold Kaczorowski

    2016-01-01

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

  10. Virological and molecular biological investigations into equine herpes virus type 2 (EHV-2) experimental infections.

    Science.gov (United States)

    Borchers, K; Wolfinger, U; Ludwig, H; Thein, P; Baxi, S; Field, H J; Slater, J D

    1998-05-01

    Two 18-month-old naturally reared ponies were used to investigate the pathogenicity of EHV-2. After dexamethasone treatment, pony 1 was inoculated intranasally with EHV-2 strain T16, which has been isolated from a foal with keratoconjunctivitis superficialis and pony 2 was similarly inoculated with strain LK4 which was originally isolated from a horse with upper respiratory tract disease. Following virus inoculation, pyrexia was not detected in either pony but both developed conjunctivitis, lymphadenopathy, and coughing. EHV-2 was detected in nasal mucus samples up to day 12 post infection (p.i.), in eye swabs up to day 10 p.i., and in buffy coat cells throughout the investigation in both animals. EHV-2-specific antibody titres were raised significantly 18 days p.i. Following the administration of dexamethasone, 3 months p.i., infectious virus was again detected in nasal mucus and conjunctival swabs from both ponies for 7 days. The tissue distribution of EHV-2 genome was studied post mortem, by means of a nested PCR. EHV-2 was detected in lymphoid tissues, lung, conjunctiva, trigeminal ganglia and olfactory lobes of pony 2, whereas in pony 1 only the conjunctiva of the left eye was PCR positive.

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

    Directory of Open Access Journals (Sweden)

    Nizar Ben Salah

    2015-10-01

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

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

    Science.gov (United States)

    Ozkan, Leyla; Erguder, Tuba H; Demirer, Goksel N

    2010-05-01

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

  13. Biomedical applications of magnesium alloys

    NARCIS (Netherlands)

    Sillekens, W.H.; Bormann, D.

    2012-01-01

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

  14. LOW DOSE MAGNESIUM SULPHATE REGIME FOR ECLAMPSIA

    Directory of Open Access Journals (Sweden)

    Bangal V

    2009-09-01

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

  15. A Search for Magnesium in Europa's Atmosphere

    CERN Document Server

    Horst, Sarah M

    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 Hubble Space Telescope Faint Object Spectrograph archival spectra of Europa's atmosphere. Magnesium was not detected and we calculate an upper limit on the magnesium column abundance. This upper limit indicates that either Europa's surface is depleted in magnesium relative to sodium and potassium, or magnesium is not sputtered as efficiently resulting in a relative depletion in its atmosphere.

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

    Energy Technology Data Exchange (ETDEWEB)

    Criscenti, Louise Jacqueline; Ockwig, Nathan W.

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Xiaoliang Wang

    2009-07-01

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

  18. 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...

  19. 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.

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

    Science.gov (United States)

    Contreras, Elizabeth Quevedo

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

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

    Directory of Open Access Journals (Sweden)

    Saeideh Momtaz

    2010-01-01

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

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

    Science.gov (United States)

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

    2010-01-01

    The present study was undertaken to explore the possible biochemical activities of Hyaenanche globosa Lamb. and its compounds. Two different extracts (ethanol and dichloromethane) of four different parts (leaves, root, stem, and fruits) of H. globosa were evaluated for their possible antibacterial, antityrosinase, and anticancer (cytotoxicity) properties. Two pure compounds were isolated using column chromatographic techniques. Active extracts and pure compounds were investigated for their antioxidant effect on cultured ‘Hela cells’. Antioxidant/oxidative properties of the ethanolic extract of the fruits of H. globosa and purified compounds were investigated using reactive oxygen species (ROS), ferric-reducing antioxidant power (FRAP), and lipid peroxidation thiobarbituric acid reactive substance (TBARS) assays. The ethanolic extract of the leaves and fruits of H. globosa showed the best activity, exhibiting a minimum inhibitory concentration (MIC) of 3.1 mg/ ml and a minimum bactericidal concentration (MBC) of 1.56 and 6.2 mg/ml, respectively, against M. smegmatis. The ethanolic extract of the fruits of H. globosa (F.E) showed the highest percentage of inhibitory activity of monophenolase (90.4% at 200 μg/ml). In addition, F.E exhibited 50% inhibitory concentration (IC50) of 37.7 μg/ml on the viability of ‘HeLa cells’ using cytotoxicity MTT assay. Subsequently, F.E was fractionated using phase-partitioning with n-hexane, ethyl acetate, and n-butanol. The cytotoxicity of these fractions were determined in vitro using different cancer cell lines. The n-hexane fraction exhibited the highest activity of toxicity. Therefore, this fraction was subjected to further separation by chromatographic methods. Two pure compounds known as: ‘Tutin’ and ‘hyenanchin’ were isolated and their structures were determined by NMR spectroscopic methods. Unpredictably, none of them showed significant (P < 0.01) inhibition on cell viability/proliferation at the

  3. 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.

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

    Science.gov (United States)

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

    2008-01-01

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

  5. Chemical and biological investigations of a toxic plant from Central Africa, Magnistipula butayei subsp. montana.

    Science.gov (United States)

    Karangwa, C; Esters, V; Frédérich, M; Tits, M; Kadima, J N; Damas, J; Noirfalise, A; Angenot, L

    2006-02-20

    Magnistipula butayei subsp. montana (Chrysobalanaceae) is known, in the Great Lakes Region, to possess toxicological properties. In this paper, we investigated the acute toxicity (dose levels 50-1600 mg/kg) of its aqueous extract, administered orally to adult Wistar rats. This study demonstrated that the freeze-dried aqueous extract (5%, w/w) possesses high toxicity. The extract caused hypothermia, neurological disorders, including extensor reflex of maximal convulsive induced-seizures at about 2 h after the administered dose, and death occurred (LD50=370 mg/kg) in a dose dependent manner. Blood parameter evaluation revealed slight variations, but these might not have clinical relevance. Histological examination of internal organs (lungs, liver, heart and kidneys) did not reveal any abnormality in the treated group compared to the control. Therefore, it can be concluded that Magnistipula butayei subsp. montana aqueous extract, given orally, is toxic and that its target is the central nervous system. General phytochemical screening revealed that the plant did not contain significant amounts of products known to be toxic, such as alkaloids or cardioactive glycosides, but only catechic tannins, amino acids, saponins and other aphrogen principles in the three parts of the species (fruit, leave and bark).

  6. COX inhibitors Indomethacin and Sulindac derivatives as antiproliferative agents: synthesis, biological evaluation, and mechanism investigation.

    Science.gov (United States)

    Chennamaneni, Snigdha; Zhong, Bo; Lama, Rati; Su, Bin

    2012-10-01

    Cyclooxygenase (COX) inhibitors Indomethacin and its structural analogs Sulindac exhibit cell growth inhibition and apoptosis inducing activities in various cancer cell lines via COX independent mechanisms. In this study, the molecular structures of Indomethacin and Sulindac were used as starting scaffolds to design novel analogs and their effects on the proliferation of human cancer cells were evaluated. Compared to Indomethacin and Sulindac inhibiting cancer cell proliferation with IC(50)s of more than 1 mM, the derivatives displayed significantly increased activities. Especially, one of the Indomethacin analogs inhibited the growth of a series of cancer cell lines with IC(50)s around 0.5 μM-3 μM. Mechanistic investigation revealed that the new analog was in fact a tubulin inhibitor, although the parental compound Indomethacin did not show any tubulin inhibitory activity. Tubulin polymerization assay indicated this compound inhibited tubulin assembly at high concentrations, but promoted this process at low concentrations which is a very unique mechanism. The binding mode of this compound in tubulin was predicted using the molecular docking simulation.

  7. Synthesis, characterization, investigation of biological activity and theoretical studies of hydrazone compounds containing choloroacetyl group

    Science.gov (United States)

    Cukurovali, Alaaddin; Yilmaz, Engin

    2014-10-01

    In this study, three new hydrazide-hydrazone derivative compounds which contain choloroacetyl group have been synthesized and characterized. In the characterization, spectral techniques such as IR, 1H NMR, 13C NMR and UV-Vis spectroscopy techniques were used. Antibacterial effects of the synthesized compounds were investigated against Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. In the theoretical calculations Gaussian 09 software was used with the DFT/6-311+(d,p) basis set. Experimental X-ray analysis of compounds has not been studied. Theoretical bond lengths of synthesized compounds were compared with experimental bond lengths of a similar compound. Theoretical and experimental bond lengths are in good agreement with R2: 0.896, 0.899 and 0.900 for compounds 1, 2, and 3, respectively. For antibacterial activity, the most effective one was found to be N‧-(4-bromobenzylidene)-2-chloro-N-(4-(3-methyl-3-phenylcyclobutyl)-thiazol-2-yl) acetohydrazide against P.aeroginaosa ATTC 27853, among the studied compounds.

  8. Biological investigations of medicinal plants of Heliotropium indicum indigenous to Bangladesh

    Directory of Open Access Journals (Sweden)

    Karim Samira

    2016-10-01

    Full Text Available Objective: To investigate the clot lysis, antimicrobic and membrane stabilizing potentials of ethanolic extractives of the leaves of Heliotropium indicum (H. indicum. Methods: Crude ethanolic extracts of H. indicum leaves were partitioned successively using solvents of different polarity and subjected to determine qualitatively and quantitatively for the presence of different bioactive constitutes and fractions which were assessed for their possible clot lysis, antimicrobic, and membrane stabilizing activities as compared with the known drugs. Results: For the thrombolytic activity, the petroleum ether soluble fraction showed the highest percent of clot lysis (35.4% among all fractions, while streptokinase and water resulted in 65.15% and 3.77% clot lysis, respectively. With respect to the membrane stabilizing activity, carbon tetrachloride soluble fraction of H. indicum profoundly interdicted the hemolysis of erythrocytes brought about by osmotic induction (39.24% or by heat (40.20%. The other fractions exhibited less significant membrane stabilizing effect. By contrast, acetylsalicylic acid resulted in 72.25% ± 0.30% inhibition of osmotically induced hemolysis and showed a lower level of protection of heat induced hemolysis (42.56%. Crude ethanolic extracts were moderately sensitive against known pathogenic microbes. Since pharmacological activities of H. indicum are due to the presence of bioactive compounds, we detected and quantified the presence of significant levels of flavonoid and tannin substances. Conclusions: The outcomes of this research show that the leaves of H. indicum have the potential to be used as a remedy for thrombosis, inflammatory diseases and against few important bacterial pathogens.

  9. Biological investigations of medicinal plants ofHeliotropium indicum indigenous to Bangladesh

    Institute of Scientific and Technical Information of China (English)

    Karim Samira; Kawsar Md.; Farhina Rahman Laboni; Azima Sultana Julie; Uddin Jalal; Zubair Khalid Labu

    2016-01-01

    Objective:To investigate the clot lysis, antimicrobic and membrane stabilizing potentials of ethanolic extractivesof the leaves ofHeliotropium indicum(H. indicum). Methods:Crude ethanolic extracts ofH. indicum leaves were partitioned successively using solvents of different polarity and subjected to determine qualitatively and quantitatively for the presence of different bioactive constitutes and fractions which were assessed for their possible clot lysis, antimicrobic, and membrane stabilizing activities as compared with the known drugs. Results:For the thrombolytic activity, the petroleum ether soluble fraction showed the highest percent of clot lysis (35.4%) among all fractions, while streptokinase and water resulted in 65.15% and 3.77% clot lysis, respectively. With respect to the membrane stabilizing activity, carbon tetrachloride soluble fraction ofH. indicum profoundly interdicted the hemolysis of erythrocytes brought about by osmotic induction (39.24%) or by heat (40.20%). The other fractions exhibited less significant membrane stabilizing effect. By contrast, acetylsalicylic acid resulted in 72.25% ± 0.30% inhibition of osmotically induced hemolysis and showed a lower level of protection of heat induced hemolysis (42.56%). Crude ethanolic extracts were moderately sensitive against known pathogenic microbes. Since pharmacological activities of H. indicum are due to the presence of bioactive compounds, we detected and quantified the presence of significant levels of flavonoid and tannin substances. Conclusions:The outcomes of this research show that the leaves ofH. indicum have the potential to be used as a remedy for thrombosis, inflammatory diseases and against few important bacterial pathogens.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  11. Influence of HEPES buffer on the local pH and formation of surface layer during in vitro degradation tests of magnesium in DMEM

    NARCIS (Netherlands)

    Naddaf Dezfuli, S.; Huan, Z.; Mol, J.M.C.; Leeflang, M.A.; Chang, J.; Zhou, J.

    2014-01-01

    The human body is a buffered environment where pH is effectively maintained. HEPES is a biological buffer often used to mimic the buffering activity of the body in in vitro studies on the degradation behavior of magnesium. However, the influence of HEPES on the degradation behavior of magnesium in t

  12. Acoustic Emission of Deformation Twinning in Magnesium

    Directory of Open Access Journals (Sweden)

    Chengyang Mo

    2016-08-01

    Full Text Available The Acoustic Emission of deformation twinning in Magnesium is investigated in this article. Single crystal testing with combined full field deformation measurements, as well as polycrystalline testing inside the scanning electron microscope with simultaneous monitoring of texture evolution and twin nucleation were compared to testing at the laboratory scale with respect to recordings of Acoustic Emission activity. Single crystal testing revealed the formation of layered twin boundaries in areas of strain localization which was accompanied by distinct changes in the acoustic data. Testing inside the microscope directly showed twin nucleation, proliferation and growth as well as associated crystallographic reorientations. A post processing approach of the Acoustic Emission activity revealed the existence of a class of signals that appears in a strain range in which twinning is profuse, as validated by the in situ and ex situ microscopy observations. Features extracted from such activity were cross-correlated both with the available mechanical and microscopy data, as well as with the Acoustic Emission activity recorded at the laboratory scale for similarly prepared specimens. The overall approach demonstrates that the method of Acoustic Emission could provide real time volumetric information related to the activation of deformation twinning in Magnesium alloys, in spite of the complexity of the propagation phenomena, the possible activation of several deformation modes and the challenges posed by the sensing approach itself when applied in this type of materials evaluation approach.

  13. Magnesium: its role in nutrition and carcinogenesis.

    Science.gov (United States)

    Blaszczyk, Urszula; Duda-Chodak, Aleksandra

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Bing Wang

    2013-12-01

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

  15. New anodizing process for magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    LUO Sheng-lian; DAI Lei; ZHOU Hai-hui; CHAI Li-yuan; KUANG Ya-fei

    2006-01-01

    Compact anodic films with high hardness and good corrosion resistance on magnesium alloys were prepared by a new constant voltage and arc-free anodizing process. The effects of anodizing parameters such as applied voltage and electrolyte temperature on the peak current density and the thickness of films were investigated. In addition, the morphologies and corrosion resistance of films were investigated by scanning electron microscopy and potentiodynamic polarization, respectively. The results show that the higher the applied voltage, the higher the peak current density and the thicker the films. However, too high applied voltage may result in breakdown of films and intense sparking which may deteriorate the properties of the anodic films and bring about unsafety. The new anodizing process can be applied in a wide range of temperature. The new anodic films have numbers of pores with the diameter of 0.5 - 5.0 μm which do not transverse the entire film.

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

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

  17. Investigating the Role of an Inquiry-Based Biology Lab Course on Student Attitudes and Views toward Science.

    Science.gov (United States)

    Jeffery, Erica; Nomme, Kathy; Deane, Thomas; Pollock, Carol; Birol, Gülnur

    2016-01-01

    Students' academic experiences can influence their conceptualization of science. In contrast experts hold particular beliefs, perceptions, opinions, and attitudes about science that are often absent in first-year undergraduate students. Shifts toward more expert-like attitudes and views have been linked to improved student engagement, critical-thinking ability, conceptual understanding, and academic performance. In this study, we investigate shifts in attitudes and views toward science by students in four biology classes with differences in student enrollment, academic support, and instruction. We observe significant, positive effects of enrollment in a guided-inquiry lab course and academic performance on the percentage of expert-like student attitudes and views at the end of term. We also identify variation in two aspects of student attitudes and views: 1) confidence and interest and 2) understanding and acceptance. In particular, enrollment in the lab course boosts student confidence and interest in scientific inquiry in the short term, even for students with low academic performance or little English-language experience. Our results suggest that low-performing students in particular may require additional opportunities for experiential learning or greater academic support to develop expert-like perceptions of biology as a science.

  18. Importance of molecular cell biology investigations in human medicine in the story of the Hutchinson-Gilford progeria syndrome.

    Science.gov (United States)

    Raška, Ivan

    2010-09-01

    Ranged among laminopathies, Hutchinson-Gilford progeria syndrome is a syndrome that involves premature aging, leading usually to death at the age between 10 to 14 years predominatly due to a myocardial infarction or a stroke. In the lecture I shall overview the importance of molecular cell biology investigations that led to the discovery of the basic mechanism standing behind this rare syndrome. The genetic basis in most cases is a mutation at the nucleotide position 1824 of the lamin A gene. At this position, cytosine is substituted for thymine so that a cryptic splice site within the precursor mRNA for lamin A is generated. This results in a production of abnormal lamin A, termed progerin, its presence in cells having a deleterious dominant effect. Depending on the cell type and tissue, progerin induces a pleiotropy of defects that vary in different tissues. The present endeavour how to challenge this terrible disease will be also mentioned.

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

    Institute of Scientific and Technical Information of China (English)

    Renguo SONG; Xiaohua ZHENG; Carsten Blawert; Wolfgang Dietzel

    2007-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    赵亚忠; 潘复生; 彭建; 王维青; 罗素琴

    2010-01-01

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

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

    Science.gov (United States)

    Kiełczykowska, Małgorzata; Pasternak, Kazimierz; Musik, Irena

    2003-01-01

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

  2. Characteristics on radiation crosslinking of low density polyethylene/magnesium dihydrate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. Y.; Lee, C.; Kim, P. J.; Kim, J. A. [KAERI, Taejon (Korea, Republic of); Ryu, B. H. [Dongguk University, Gyeongju (Korea, Republic of)

    2004-07-01

    This study has investigated the flame retardant properties of polyethylene with addition of flame retardant and gaseous conditions. It is sample that PE was blended with magnesium dihydrate to 10, 20, 30phr. The samples were irradiated using a Co{sup 60} {gamma}-ray in nitrogen, oxygen and air atmosphere. Elongation at break of PE was made up of various gaseous conditions, decreased by magnesium dihydrate content increase. And we measured LOI(limited oxygen index) for flame retardant property, LOI increased by magnesium dihydrate content increase. The flame retardant property was improved.

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

    Science.gov (United States)

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

    2007-11-13

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

  4. [Magnesium deficiency and therapy in cardiac arrhythmias: recommendations of the German Society for Magnesium Research].

    Science.gov (United States)

    Vierling, W; Liebscher, D-H; Micke, O; von Ehrlich, B; Kisters, K

    2013-05-01

    Aim of the recommendations of the German Society for Magnesium Research: Recognition and compensation of magnesium deficiency in patients with risk factors for cardiac arrhythmias or manifest rhythm disturbances. Prevention of arrhythmias by administration of magnesium. Therapeutic administration of magnesium in patients with arrhythmias with and without magnesium deficiency. The current state of knowledge claims for considering the status of magnesium and the possibility of a therapeutic intervention with magnesium within the concept of the treatment of cardiovascular diseases. The use of magnesium as single agent or as an adjunct to other therapeutic actions in the prevention and therapy of cardiac arrhythmias can be effective and, in case of oral administration, very safe. In case of parenteral administration, it is important to use adequate doses, monitor cardiovascular and neuromuscular parameters and to consider contraindications.

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

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Riisager, Anders

    2011-01-01

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

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

    Science.gov (United States)

    Linsheng, Li; Guoxiang, Lin; Lihui, Li

    2016-08-12

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

  7. 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.

  8. 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.

  9. Laser surface treatment of magnesium alloys with aluminium oxide powder

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2009-11-01

    Full Text Available Purpose: The aim of this paper was to improve the magnesium cast alloys surface layer by laser surface treatment and to determine the laser treatment parameters.Design/methodology/approach: The laser treatment of magnesium alloys with alloying Al2O3 powder of the particle about 80μm was carried out using a high power diode laser (HPDL. The resulting microstructure in the modified surface layer was examined using scanning electron microscopy. Phase composition was determined by the X-ray diffraction method using the XPert device. The measurements of microhardness of the modified surface layer were also studied.Findings: The alloyed region has a fine microstructure with hard carbide particles. Microhardness of laser surface alloyed layer was significantly improved as compared to an alloy without laser treatment.Research limitations/implications: The investigations were conducted for cast magnesium alloys MCMgAl12Zn1, MCMgAl9Zn1, MCMgAl6Zn1, MCMgAl3Zn1 and Al2O3 powder of the particle size about 80 μm. One has used laser power in the range from 1.2to 2.0 kW.Practical implications: The results obtained in this investigation were promising comparing with the other conventional processes. High Power Diode Laser can be used as an economical substitute of Nd: YAG and CO2 to improve the surface magnesium alloy by feeding the carbide particles.Originality/value: The value of this paper is to define the influence of laser treatment parameters on quality, microstructure and microhardness of magnesium cast alloys surface layer.

  10. Crystallization of Esomeprazole Magnesium Water/Butanol Solvate

    Directory of Open Access Journals (Sweden)

    Jenna Skieneh

    2016-04-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

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

    Science.gov (United States)

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

    2009-01-01

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

  13. Airway surface liquid contains endogenous DNase activity which can be activated by exogenous magnesium

    Directory of Open Access Journals (Sweden)

    Rosenecker J

    2009-07-01

    Full Text Available Abstract Introduction The removal of highly viscous mucus from the airways is an important task in the treatment of chronic lung disease like in cystic fibrosis. The inhalation of recombinant human DNase-I (rhDNase-I is used to facilitate the removal of tenacious airway secretions in different lung diseases and especially in CF. Little is known about endogenous DNase activity in the airway surface liquid. Therefore, we analysed bronchoalveolar lavage fluid (BAL and exhaled breath condensate (EBC for the presence of endogenous DNase activity. Methods The degradation of plasmid DNA by BAL from patients who had diagnostic bronchoscopy and bronchoalveolar lavage was analyzed. In a group of CF patients and healthy control volunteers the exhaled breath condensate was obtained and also analyzed for the ability to degrade plasmid DNA. In addition, the ability of magnesium to activate endogenous DNase activity in BAL and exhaled breath condensate was investigated. Results The analyzed BAL samples degraded plasmid DNA only after preincubation with magnesium. When analyzing the exhaled breath condensate the samples obtained from the healthy volunteers showed no DNase activity even after preincubation with magnesium, whereas in one of the two samples obtained from CF patients we found a DNase activity after preincubation with magnesium. Conclusion Increasing the magnesium concentration in the airway surface liquid by aerosolisation of magnesium solutions or oral magnesium supplements could improve the removal of highly viscous mucus in chronic lung disease by activating endogenous DNase activity.

  14. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  16. Attitude toward the biological investigation for decreasing atmospheric CO2. Taiki CO2 wo sakugensuru seibutsuteki kenkyu taido

    Energy Technology Data Exchange (ETDEWEB)

    1993-08-01

    Explanation is made of the bioprocess which aims at treating the atmospheric CO2. As a result of investigation by the Electric Power Research Institute (EPRI), it was judged that the direct CO2 removal from the flue gas of power station is costwise disadvantageous and that the biological method by CO2 fixation is economical. The following are projects supported by the EPRI: The seaweed fossilization of CO2 is a medium depth sea mechanism of having seaweeds absorb carbon and making it remain residually in the deepsea even after the plants die. Study is being made of oceanic seaweed cultivation field development, non-calcareous seaweed cultivation and spore collection. The cost is advantageously low. The cultivation of seaweeds and halophilous plants utilizes their photosynthesis to collect CO2. There are examples of studying the possibility of cultivating those plants through comparison with the land trees. The growth ratio of halophilous plants is being also studied together with the possibility that the carbon remains as a residue. The whiting is a phenomenon in which biodecomposed subsea matter becomes CaCO3. Covered with CaCO3, the ssaweeds are deposited. Investigation is being made on the seaweed morphology and condition for the occurrence of whiting. 1 ref., 2 figs., 1 tab.

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

    Directory of Open Access Journals (Sweden)

    Andre Schmandke

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

  18. Preliminary investigation on the effects of biological and synthetic insecticides on large white butterfly (Pieris brassicae L. larvae

    Directory of Open Access Journals (Sweden)

    Klokočar-Šmit Zlata D.

    2007-01-01

    Full Text Available Control of cabbage pests is oriented towards the use of efficient but high-risk insecticides, some of them being endocrine disruptors. Biopesticides are more environment-friendly, operator-and consumers-safe, but they have low initial toxicity, low efficacy to advanced larval stages, and they require certain knowledge of pest and host biology. In our laboratory experiments we have investigated the effects of formulated synthetic pyrethroid cypermethrin (0.3 l/ha and biological products - formulations based on Bacillus thuringiensis subsp. kurstaki (2 and 3/ha and Spinosad (0.1 l/ha - on large white butterfly (Pieris brassicae L. larvae-instars 2, 3, 4 and 5. The effect of insecticides was inversely proportional to larval instars. Btk effect could be improved if tank-mixed with cypermethrin. The mixing of ready-made products allows a reduction 3 and 6 times compared with the recommended dose, still obtaining satisfactory results. Rate of leaf damage was reduced when tank mixtures were used. Use of two products in mixture would be of significance especially for control of advanced late instars late in season, when Btk action alone is insufficient. Spinosad was effective in inducing mortality and reducing leaf damage by all larval instars, therefore we assume that the dose could be reduced. Feeding rate and mortality are equally important parameters when assessing biopesticide efficacy. This strategy should also reduce the possibility of inducing resistance in pest population. It also tends to reduce the residues in commodities and is good solution in production of hygienic and health safe food.

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

    Science.gov (United States)

    Pasukphun, N; Vinitnantharat, S; Gheewala, S

    2010-04-01

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

  20. Nanocomposite polymer electrolyte for rechargeable magnesium batteries

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-28

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

  1. Hydrogen desorption from nanostructured magnesium hydride composites

    Directory of Open Access Journals (Sweden)

    Brdarić Tanja P.

    2007-01-01

    Full Text Available The influence of 3d transition metal addition (Fe, Co and Ni on the desorption properties of magnesium hydride were studied. The ball milling of MgH2-3d metal blends was performed under Ar. Microstructural and morphological characterization were performed by XRD and SEM analysis, while the hydrogen desorption properties were investigated by DSC. The results show a strong correlation between the morphology and thermal stability of the composites. The complex desorption behavior (the existence of more than one desorption peak was correlated with the dispersion of the metal additive particles that appear to play the main role in the desorption. The desorption temperature can be reduced by more than 100 degrees if Fe is added as additive. The activation energy for H2 desorption from the MgH2-Fe composite is 120 kJ/mol, implying that diffusion controls the dehydration process.

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

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

    Science.gov (United States)

    Wu, L; He, H

    1994-05-01

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

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

    OpenAIRE

    H.Watari; Haga, T.; Davey, K.; Koga, N; Yamazaki, T.

    2006-01-01

    Purpose: : The purpose of the work is to establish a manufacturing process and technology to facilitate the economical manufacture of high-quality magnesium sheet alloys.Design/methodology/approach: Magnesium alloy AZ31B was used to investigate the appropriate manufacturing conditions for use in twin-roll strip casting. Temperatures of the molten materials and roll speeds were varied to find the appropriate manufacturing conditions. The effects of manufacturing conditions on possible forming ...

  5. Study on Semi-solid Rheocasting Forming for Magnesium Alloy by Mechanical Stirring

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper the effect of pouring temperature of magnesium melt, preheating temperature of the barrel of screw mixer and shear rate on the solidified microstructures of semi-solid slurry was investigated by mechanical stirring method. The appropriate processing parameters of slurry preparation were obtained. The mold filling for thin walled casting was examined. Results indicated that the solid volume fraction of non-dendritic structure increased with decrease in pouring temperature of magnesium melt and ...

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

    Science.gov (United States)

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

    2013-07-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  8. AZ31镁合金表面纳米陶瓷涂层的组织与力学性能分析%Investigation on microstructure and mechanical properties of nano-ceramic coating on AZ31 magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    高正源; 潘复生

    2012-01-01

    In order to improve the wear-resisting property of magnesium alloy’s surface coating,Al2O3 nano-ceramic coating on the surface of AZ31 magnesium alloy is prepared using the magnetron sputtering process.Influences of temperature,power and time on hardness of surface layer are discussed by orthogonal method.Morphology,phases and composition of coatings are analyzed by SEM,XRD and EDS.The results show that the time and power are important factors to affect hardness and wear resistance.The process parameters of 80 ℃,200 W and 3 h are the optimal sputtering process.Through this process,the thickness of nano-Al2O3 coating on AZ31 is about 2 to 10 μm and the grain size is about 30 nm.The surface hardness of ceramic coating reaches up to 1 360 MPa,and increases more than 77.31% of the substrate hardness of nano-Al2O3 coating.%为改善镁合金表面的耐磨性能,采用磁控溅射工艺在AZ31镁合金表面制备了纳米Al203陶瓷涂层。用XRD、SEM-EDS等分析了涂层的结构和形貌,用正交试验讨论了温度、功率、时间对涂层表面硬度的影响规律。结果表明,影响纳米Al2O3膜硬度和耐磨性的因素是溅射功率和溅射时间,最佳的工艺为80℃,200W,3h。采用本工艺技术,材料表面主要为2~10um厚、30nm左右的粒状δ-Al2O3致密层,表层硬度从基体767MPa提高为1 360MPa,提高了77.31%。

  9. Magnesium ion-conducting gel polymer electrolytes dispersed with nanosized magnesium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, G.P. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Solid State Ionics Research Laboratory, School of Studies in Physics, Pt. Ravishankar Shukla University, Raipur 492010, C.G. (India); Agrawal, R.C. [Solid State Ionics Research Laboratory, School of Studies in Physics, Pt. Ravishankar Shukla University, Raipur 492010, C.G. (India); Hashmi, S.A. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2009-05-15

    Experimental investigations are performed on novel magnesium ion-conducting gel polymer electrolyte nanocomposites based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), dispersed with nanosized magnesium oxide (MgO) particles. The nanocomposite materials are in the form of free-standing films. Various physical and electrochemical analyses demonstrate promising characteristics of these films, suitable as electrolytes in rechargeable magnesium batteries. The optimized material with 3 wt.% MgO offers a maximum electrical conductivity of {proportional_to}8 x 10{sup -3} S cm{sup -1} at room temperature ({proportional_to}25 C) with good thermal and electrochemical stabilities. The ion/filler-polymer interactions and possible conformational changes in host polymer PVdF-HFP due to the liquid electrolyte entrapment and dispersion of nanosized MgO are examined by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscopic (SEM) methods. The Mg{sup 2+} ion conduction in the gel film is confirmed from the cyclic voltammetry, impedance spectroscopy and transport number measurements. The Mg{sup 2+} ion transport number (t{sub +}) is enhanced substantially and found to have a maximum of {proportional_to}0.44 for the addition of 10 wt.% MgO nanoparticles. The enhancement in t{sub +} is explained on the basis of the formation of space-charge regions due to the presence of MgO:Mg{sup 2+}-like species, that supports Mg{sup 2+} ion motion. (author)

  10. Cathodic phosphate coating containing nano zinc particles on magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A technology for preparation of a cathodic phosphate coating mainly containing nano metallic zinc particles and phosphate compounds on magnesium alloy was developed.The influence of cathodic current density on the microstructure of the cathodic phosphate coating Was investigated.The results show that the crystals of the coating are finer and the microstructures of the outer surface of the coatings are zigzag at the cathodic density of 0.2-0.5 A/dm2.The content of nano metallic zinc particles in the coating decreases with the increase of the thickness of the coatings and tends to be zero when the coating thickness is 4.14 μm.The cathodic phosphate coating was applied to be a transition coating for improving the adhesion between the paints and the magnesium alloys.The formation mechanism of the cathodic phosphate coating was investigated as well.

  11. Microstructure of MCMgAl12Zn1 magnesium alloy

    Directory of Open Access Journals (Sweden)

    Dobrzański L. A.

    2007-01-01

    Full Text Available In this paper is presented the structure of the cast magnesium alloys as cast state and after heat treatment cooled with different cooling rate, depending on the cooling medium (furnace, water, air. For investigations samples in shape of 250x150x25 mm plates were used. The structure have been study in the light microscope, scanning electron microscope equipped with an electron back scattering facility. The effects of the addition of Al on the microstructure were also studied. In the analysed alloys a structure of α solid solution and fragile phase β(Mg17Al12 occurred mainly on grain borders as well as eutectic and phase with Mn, Fe and Si. Investigation are carried out for the reason of chemical composition influence and precipitation processes influence to the structure and mechanical properties of the magnesium cast alloys with different chemical composition in as cast alloys and after heat treatment.

  12. The structure and regulation of magnesium selective ion channels.

    Science.gov (United States)

    Payandeh, Jian; Pfoh, Roland; Pai, Emil F

    2013-11-01

    The magnesium ion (Mg(2+)) is the most abundant divalent cation within cells. In man, Mg(2+)-deficiency is associated with diseases affecting the heart, muscle, bone, immune, and nervous systems. Despite its impact on human health, little is known about the molecular mechanisms that regulate magnesium transport and storage. Complete structural information on eukaryotic Mg(2+)-transport proteins is currently lacking due to associated technical challenges. The prokaryotic MgtE and CorA magnesium transport systems have recently succumbed to structure determination by X-ray crystallography, providing first views of these ubiquitous and essential Mg(2+)-channels. MgtE and CorA are unique among known membrane protein structures, each revealing a novel protein fold containing distinct arrangements of ten transmembrane-spanning α-helices. Structural and functional analyses have established that Mg(2+)-selectivity in MgtE and CorA occurs through distinct mechanisms. Conserved acidic side-chains appear to form the selectivity filter in MgtE, whereas conserved asparagines coordinate hydrated Mg(2+)-ions within the selectivity filter of CorA. Common structural themes have also emerged whereby MgtE and CorA sense and respond to physiologically relevant, intracellular Mg(2+)-levels through dedicated regulatory domains. Within these domains, multiple primary and secondary Mg(2+)-binding sites serve to staple these ion channels into their respective closed conformations, implying that Mg(2+)-transport is well guarded and very tightly regulated. The MgtE and CorA proteins represent valuable structural templates to better understand the related eukaryotic SLC41 and Mrs2-Alr1 magnesium channels. Herein, we review the structure, function and regulation of MgtE and CorA and consider these unique proteins within the expanding universe of ion channel and transporter structural biology.

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    Akshay Gurdita

    Full Text Available Basic equipment such as incubation and refrigeration systems plays a critical role in nearly all aspects of the traditional biological research laboratory. Their proper functioning is therefore essential to ensure reliable and repeatable experimental results. Despite this fact, in many academic laboratories little attention is paid to validating and monitoring their function, primarily due to the cost and/or technical complexity of available commercial solutions. We have therefore developed a simple and low-cost monitoring system that combines a "Raspberry Pi" single-board computer with USB-connected sensor interfaces to track and log parameters such as temperature and pressure, and send email alert messages as appropriate. The system is controlled by open-source software, and we have also generated scripts to automate software setup so that no background in programming is required to install and use it. We have applied it to investigate the behaviour of our own equipment, and present here the results along with the details of the monitoring system used to obtain them.

  15. Considerations for the use of human participants in vector biology research: a tool for investigators and regulators.

    Science.gov (United States)

    Achee, Nicole L; Youngblood, Laura; Bangs, Michael J; Lavery, James V; James, Stephanie

    2015-02-01

    A thorough search of the existing literature has revealed that there are currently no published recommendations or guidelines for the interpretation of US regulations on the use of human participants in vector biology research (VBR). An informal survey of vector biologists has indicated that issues related to human participation in vector research have been largely debated by academic, national, and local Institutional Review Boards (IRBs) in the countries where the research is being conducted, and that interpretations and subsequent requirements made by these IRBs have varied widely. This document is intended to provide investigators and corresponding scientific and ethical review committee members an introduction to VBR methods involving human participation and the legal and ethical framework in which such studies are conducted with a focus on US Federal Regulations. It is also intended to provide a common perspective for guiding researchers, IRB members, and other interested parties (i.e., public health officials conducting routine entomological surveillance) in the interpretation of human subjects regulations pertaining to VBR.

  16. Production of sorption functional media (SFM) from clinoptilolite tailings and its performance investigation in a biological aerated filter (BAF) reactor.

    Science.gov (United States)

    Feng, Yan; Qi, Jingyao; Chi, Liying; Wang, Dong; Wang, Zhaoyang; Li, Ke; Li, Xin

    2013-02-15

    The few reuse and large stockpile of zeolite tailings led to a series of social and environmental problems. This study investigated the possibility of using the zeolite tailings as one of principal raw materials to prepare sorption functional media (SFM) by a high temperature sintering process. The SFM was used to serve as a biomedium in a biological aerated filter (BAF) reactor for domestic wastewater treatment, and its purification performance was examined. The physical, chemical and sorption properties of SFM were also determined. The microstructure of the SFM was analyzed by scanning electron microscopy (SEM). Results revealed that: (1) zeolite tailings could be used to produce the SFM under the optimal sintering parameters; (2) the sorption and desorption isotherm of ammonia nitrogen on SFM could be well described by the Langmuir formula; (3) in terms of removing organic matter, ammonia nitrogen, turbidity and colourity, the performance of the biofilter with SFM was superior to that with haydite; and (4) SFM BAF has a stronger adaptability to low temperature (6-11°C) for NH(3)-N removal compared to haydite BAF. Therefore, the SFM produced from the zeolite tailings was suitable to serve as the biomedium in the domestic wastewater treatment.

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

    Science.gov (United States)

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

    2015-01-01

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

  18. Preface of the "Symposium on Mathematical Models and Methods to investigate Heterogeneity in Cell and Cell Population Biology"

    Science.gov (United States)

    Clairambault, Jean

    2016-06-01

    This session investigates hot topics related to mathematical representations of cell and cell population dynamics in biology and medicine, in particular, but not only, with applications to cancer. Methods in mathematical modelling and analysis, and in statistical inference using single-cell and cell population data, should contribute to focus this session on heterogeneity in cell populations. Among other methods are proposed: a) Intracellular protein dynamics and gene regulatory networks using ordinary/partial/delay differential equations (ODEs, PDEs, DDEs); b) Representation of cell population dynamics using agent-based models (ABMs) and/or PDEs; c) Hybrid models and multiscale models to integrate single-cell dynamics into cell population behaviour; d) Structured cell population dynamics and asymptotic evolution w.r.t. relevant traits; e) Heterogeneity in cancer cell populations: origin, evolution, phylogeny and methods of reconstruction; f) Drug resistance as an evolutionary phenotype: predicting and overcoming it in therapeutics; g) Theoretical therapeutic optimisation of combined drug treatments in cancer cell populations and in populations of other organisms, such as bacteria.

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

    Science.gov (United States)

    Gurdita, Akshay; Vovko, Heather; Ungrin, Mark

    2016-01-01

    Basic equipment such as incubation and refrigeration systems plays a critical role in nearly all aspects of the traditional biological research laboratory. Their proper functioning is therefore essential to ensure reliable and repeatable experimental results. Despite this fact, in many academic laboratories little attention is paid to validating and monitoring their function, primarily due to the cost and/or technical complexity of available commercial solutions. We have therefore developed a simple and low-cost monitoring system that combines a "Raspberry Pi" single-board computer with USB-connected sensor interfaces to track and log parameters such as temperature and pressure, and send email alert messages as appropriate. The system is controlled by open-source software, and we have also generated scripts to automate software setup so that no background in programming is required to install and use it. We have applied it to investigate the behaviour of our own equipment, and present here the results along with the details of the monitoring system used to obtain them.

  20. Magnesium removal in the electrolytic zinc industry

    NARCIS (Netherlands)

    Booster, J.L.

    2003-01-01

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

  1. Destabilization of magnesium hydride through interface engineering

    NARCIS (Netherlands)

    Mooij, L.P.A.

    2013-01-01

    The aim of this thesis is to study the thermodynamics of hydrogenation of nanoconfined magnesium within a thin film multilayer model system. Magnesium hydride is a potential material for hydrogen storage, which is a key component in a renewable energy system based on hydrogen. In bulk form, magnesiu

  2. New perspective in the assessment of total intracellular magnesium

    Directory of Open Access Journals (Sweden)

    Azzurra Sargenti

    2014-01-01

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

  3. Infrared measurement and simulation of magnesium alloy welding temperature field

    Institute of Scientific and Technical Information of China (English)

    LIU Liming; CHI Mingsheng; HUANG Ruisheng; SONG Gang; ZHOU Yang

    2005-01-01

    The welding temperature field of magnesium alloy AZ31 welded by TIG was measured with the uncooled infrared (IR) thermal imaging technology. The variables in the mathematic mode of welding temperature fields were revised by IR temperature data. Based on the results of simulation, the loss of temperature fields caused by arc interfered was compensated, and a whole temperature field was achieved, which provided a precise and powerful foundation for the investigation of microstructure of the joints.

  4. Microstructure and texture evolution of AZ31 magnesium alloy during rolling

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The production of magnesium alloy sheets normally involves several processing stages including hot rolling, cold rolling and intermediate annealing. The microstructure and texture evolution of AZ31 magnesium alloy sheets in different processing states were investigated by optical microscopy and X-ray diffraction technique. It is found that the microstructure of hot-rolled sheets is dominated by recrystallized equiaxed grains, while that of cold-rolled sheets is dominated by deformation twins. With final annealing applied on the cold-rolled sheets, fine recrystallization grains are obtained and ductility of the samples is increased. It is also found that the texture of magnesium alloy sheets prefers the basal texture, and other compositions of texture are relatively weak. Moreover,final annealing does not significantly affect texture distribution. The results of this study provide useful guidelines for optimizing the processing of magnesium alloys.

  5. Synthesis, characterization and study of antioxidant activity of quercetin-magnesium complex.

    Science.gov (United States)

    Ghosh, Nilanjan; Chakraborty, Tania; Mallick, Sougata; Mana, Supriya; Singha, Deepanwita; Ghosh, Balaram; Roy, Souvik

    2015-12-05

    Quercetin (3,3',4',5,7-pentahydroxyflavone) one of the most abundant dietary flavonoids, has been investigated in the presence of magnesium (II) in methanol. The complex formation between quercetin and magnesium (II) was examined under UV-visible, Infra-red and (1)H NMR spectroscopic techniques. The spectroscopic data denoted that quercetin can reacts with magnesium cation (Mg(+2)) through the chelation site in the quercetin molecule. The free radical antioxidant activity of the complex with respect to the parent molecule was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. It was observed that the free radical scavenging activity of quercetin was increased after complexation of magnesium (Mg(+2)) cation.

  6. Grain refinement of Mg-Al magnesium alloys by carbon inoculation

    Institute of Scientific and Technical Information of China (English)

    WANG Zhao-hui; KANG Yong-lin; ZHAO Hong-jin; XU Yue

    2006-01-01

    C2Cl6 was used as grain refiner for AM60 magnesium alloys. The effects of grain refinement process on chemical composition, microstructure, impact energy, hardness and mechanical properties of magnesium alloys were investigated with XRF spectrometer, optical and electronic microscopes, pendulum impact tester, hardness tester and MTS material testing machine. The results show that C2Cl6 has good effects on microstructure and mechanical properties of AM60 magnesium alloys. The optimum usage of C2Cl6 in AM60 for getting the best properties is 1.0%. The results of electronic microscopic examination and theoretical analyses show that Al4C3 should be the potent heterogeneous nucleant for Mg-Al magnesium alloys.

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

    Science.gov (United States)

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

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

  8. In vitro studies of biomedical magnesium alloys in a simulated physiological environment: a review.

    Science.gov (United States)

    Xin, Y; Hu, T; Chu, P K

    2011-04-01

    In spite of the immense potential of biodegradable magnesium alloys, the fast degradation rates of Mg-based biomedical implants in the physiological environment impose severe limitations in many clinical applications. Consequently, extensive in vitro studies have been carried out to investigate the materials' performance and fathom the associated mechanisms. Here, an up-to-date review of the in vitro studies on biomedical magnesium alloys in a simulated physiological environment is provided. This review focuses on four topics: (1) materials selection and in vitro biocompatibility of biomedical magnesium alloys; (2) in vitro degradation of biomedical magnesium alloys in simulated physiological environments, specifically discussing corrosion types, degradation rates, corrosion products and impact of the constituents in body fluids on materials degradation; (3) selection of suitable test media for in vitro assessment; and (4) future research trends.

  9. A novel dual nickel coating on AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Magnesium alloys covered with metal coating display excellent corrosion resistance,wear resistance,conductivity and electromagnetic shielding properties.The electroless plating Ni-P as boRom layer following the electroplating nickel as surface layer on AZ91D magnesium alloy was investigated.The coating surface morphology was observed with SEM and the structure was analyzed with XRD.Electrochemical tests and salt spray tests were carried out to study the corrosion resistance.The experimental results indicate that the dual coating is uniform,compact and pore-free.The adhesion strength between magnesium alloy substrate and electroless plating Ni-P bottom layer and electroplating nickel surface layer is perfect.The corrosion resistance of AZ91D magnesium alloy is greatly improved after being protected with the dual coating.

  10. Removal of organic magnesium in coccolithophore calcite

    Science.gov (United States)

    Blanco-Ameijeiras, S.; Lebrato, M.; Stoll, H. M.; Iglesias-Rodriguez, M. D.; Méndez-Vicente, A.; Sett, S.; Müller, M. N.; Oschlies, A.; Schulz, K. G.

    2012-07-01

    Coccolithophore calcite refers to the plates of calcium carbonate (CaCO3) produced by the calcifying phytoplankton, coccolithophores. The empirical study of the elemental composition has a great potential in the development of paleoproxies. However, the difficulties to separate coccolithophore carbonates from organic phases hamper the investigation of coccoliths magnesium to calcium ratios (Mg/Ca) in biogeochemical studies. Magnesium (Mg) is found in organic molecules in the cells at concentrations up to 400 times higher than in inorganically precipitated calcite in present-day seawater. The aim of this study was to optimize a reliable procedure for organic Mg removal from coccolithophore samples to ensure reproducibility in measurements of inorganic Mg in calcite. Two baseline methods comprising organic matter oxidations with (1) bleach and (2) hydrogen peroxide (H2O2) were tested on synthetic pellets, prepared by mixing reagent grade CaCO3 with organic matter from the non-calcifying marine algae Chlorella autotrophica and measured with an ICP-AES (inductively coupled plasma-atomic emission spectrometer). Our results show that treatments with a reductive solution [using hydroxylamine-hydrochloride (NH2OH·HCl + NH4OH)] followed by three consecutive oxidations (using H2O2) yielded the best cleaning efficiencies, removing >99% of organic Mg in 24 h. P/Ca and Fe/Ca were used as indicators for organic contamination in the treated material. The optimized protocol was tested in dried coccolithophore pellets from batch cultures of Emiliania huxleyi, Calcidiscus leptoporus and Gephyrocapsa oceanica. Mg/Ca of treated coccolithophores were 0.151 ± 0.018, 0.220 ± 0.040, and 0.064 ± 0.023 mmol/mol, respectively. Comparison with Mg/Ca literature coccolith values, suggests a tight dependence on modern seawater Mg/Ca, which changes as a consequence of different seawater origins (protocol applicable to field and laboratory studies of trace elemental composition in

  11. Magnesium in obstetric anesthesia and intensive care.

    Science.gov (United States)

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

    2017-02-01

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

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

    Directory of Open Access Journals (Sweden)

    H. Watari

    2006-04-01

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

  13. Tape casting of magnesium oxide.

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, Alicia; Corral, Erica L.; Loehman, Ronald E.; Bencoe, Denise Nora; Reiterer, Markus; Shah, Raja A.

    2008-02-01

    A tape casting procedure for fabricating ceramic magnesium oxide tapes has been developed as a method to produce flat sheets of sintered MgO that are thin and porous. Thickness of single layer tapes is in the range of 200-400 {micro}m with corresponding surface roughness values in the range of 10-20 {micro}m as measured by laser profilometry. Development of the tape casting technique required optimization of pretreatment for the starting magnesium oxide (MgO) powder as well as a detailed study of the casting slurry preparation and subsequent heat treatments for sintering and final tape flattening. Milling time of the ceramic powder, plasticizer, and binder mixture was identified as a primary factor affecting surface morphology of the tapes. In general, longer milling times resulted in green tapes with a noticeably smoother surface. This work demonstrates that meticulous control of the entire tape casting operation is necessary to obtain high-quality MgO tapes.

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

    DEFF Research Database (Denmark)

    Pyndt Jørgensen, Bettina; Winther, Gudrun; Kihl, Pernille;

    2015-01-01

    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. RESULTS: We demonstrated......OBJECTIVE: Magnesium deficiency has been associated with anxiety in humans, and rodent studies have demonstrated the gut microbiota to impact behaviour. METHODS: We investigated the impact of 6 weeks of dietary magnesium deficiency on gut microbiota composition and anxiety-like behaviour...... 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. CONCLUSION: Magnesium deficiency...

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

    Science.gov (United States)

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

    2015-04-01

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

  16. Pretreated magnesite as a source of low-cost magnesium for producing struvite from urine in Nepal.

    Science.gov (United States)

    Krähenbühl, Manuel; Etter, Bastian; Udert, Kai M

    2016-01-15

    Struvite is a solid phosphorus fertilizer that can be recovered easily from source-separated urine by dosing it with a soluble form of magnesium. The process is simple and low-cost, however, previous studies have shown that the cost of magnesium in low-income countries is crucial to the viability and implementation of struvite precipitation. Literature has proposed producing inexpensive magnesium locally by making magnesium oxide from magnesite. This paper aimed to investigate whether process requirements, costs, and environmental impacts would make this process viable for magnesium production in decentralized settings. Magnesite samples were calcined at temperatures between 400 °C and 800 °C and for durations between 0.5 h and 6 h. The release of magnesium was tested by dissolution in phosphate-depleted urine. The optimal processing conditions were at 700 °C for 1h: magnesite conversion was incomplete at lower temperatures, and the formation of large crystallites caused a decrease in solubility at higher temperatures. The narrow optimal range for magnesium production from magnesite requires reliable process control. Cost estimations for Nepal showed that using local magnesite would provide the cheapest source of magnesium and that CO2 emissions from transport and production would be negligible compared to Nepal's overall CO2 emissions.

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

    Science.gov (United States)

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

    2016-01-01

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

  18. Systems biology investigation of cAMP modulation to increase SMN levels for the treatment of spinal muscular atrophy.

    Directory of Open Access Journals (Sweden)

    Sean G Mack

    Full Text Available Spinal muscular atrophy (SMA, a leading genetic cause of infant death worldwide, is an autosomal recessive disorder caused by the loss of SMN1 (survival motor neuron 1, which encodes the protein SMN. The loss of SMN1 causes a deficiency in SMN protein levels leading to motor neuron cell death in the anterior horn of the spinal cord. SMN2, however, can also produce some functional SMN to partially compensate for loss of SMN1 in SMA suggesting increasing transcription of SMN2 as a potential therapy to treat patients with SMA. A cAMP response element was identified on the SMN2 promoter, implicating cAMP activation as a step in the transcription of SMN2. Therefore, we investigated the effects of modulating the cAMP signaling cascade on SMN production in vitro and in silico. SMA patient fibroblasts were treated with the cAMP signaling modulators rolipram, salbutamol, dbcAMP, epinephrine and forskolin. All of the modulators tested were able to increase gem formation, a marker for SMN protein in the nucleus, in a dose-dependent manner. We then derived two possible mathematical models simulating the regulation of SMN2 expression by cAMP signaling. Both models fit well with our experimental data. In silico treatment of SMA fibroblasts simultaneously with two different cAMP modulators resulted in an additive increase in gem formation. This study shows how a systems biology approach can be used to develop potential therapeutic targets for treating SMA.

  19. Production of sorption functional media (SFM) from clinoptilolite tailings and its performance investigation in a biological aerated filter (BAF) reactor

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yan [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); School of Civil Engineering and Architecture, University of Jinan, Jinan 250022 (China); Qi, Jingyao, E-mail: qjy_hit@yahoo.cn [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Chi, Liying [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Wang, Dong [School of Civil Engineering and Architecture, University of Jinan, Jinan 250022 (China); Wang, Zhaoyang; Li, Ke; Li, Xin [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2013-02-15

    Highlights: ► Sorption functional media (SFM) were prepared using zeolite tailings. ► Two upflow BAFs were applied to treat municipal wastewater. ► SFM BAF brought a relative superiority to haydite reactor. ► SFM BAF has a stronger adaptability to low temperature (6–11°C) for NH{sub 3}-N removal. ► The application provided a promising way in zeolite tailings utilization. -- Abstract: The few reuse and large stockpile of zeolite tailings led to a series of social and environmental problems. This study investigated the possibility of using the zeolite tailings as one of principal raw materials to prepare sorption functional media (SFM) by a high temperature sintering process. The SFM was used to serve as a biomedium in a biological aerated filter (BAF) reactor for domestic wastewater treatment, and its purification performance was examined. The physical, chemical and sorption properties of SFM were also determined. The microstructure of the SFM was analyzed by scanning electron microscopy (SEM). Results revealed that: (1) zeolite tailings could be used to produce the SFM under the optimal sintering parameters; (2) the sorption and desorption isotherm of ammonia nitrogen on SFM could be well described by the Langmuir formula; (3) in terms of removing organic matter, ammonia nitrogen, turbidity and colourity, the performance of the biofilter with SFM was superior to that with haydite; and (4) SFM BAF has a stronger adaptability to low temperature (6–11 °C) for NH{sub 3}-N removal compared to haydite BAF. Therefore, the SFM produced from the zeolite tailings was suitable to serve as the biomedium in the domestic wastewater treatment.

  20. Microwave assisted synthesis and characterization of magnesium substituted calcium phosphate bioceramics

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Nida Iqbal [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan); Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Ijaz, Kashif; Zahid, Muniza; Khan, Abdul S. [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan); Abdul Kadir, Mohammed Rafiq [Medical Implant Technology Group (MEDITEG), Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim (Malaysia); Hussain, Rafaqat [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johore (Malaysia); Anis-ur-Rehman [Department of Physics, COMSATS Institute of Information Technology, Chakshahzad Campus, Islamabad (Pakistan); Darr, Jawwad A. [Clean Materials Technology Group, Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Ihtesham-ur-Rehman [The Kroto Research Institute, North Campus, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom); Chaudhry, Aqif A., E-mail: aqifanwar@ciitlahore.edu.pk [Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, M. A. Jinnah Campus, Defence Road, Off Raiwind Road, Lahore (Pakistan)

    2015-11-01

    Hydroxyapatite is used extensively in hard tissue repair due to its biocompatibility and similarity to biological apatite, the mineral component of bone. It differs subtly in composition from biological apatite which contains other ions such as magnesium, zinc, carbonate and silicon (believed to play biological roles). Traditional methods of hydroxyapatite synthesis are time consuming and require strict reaction parameter control. This paper outlines synthesis of magnesium substituted hydroxyapatite using simple microwave irradiation of precipitated suspensions. Microwave irradiation resulted in a drastic decrease in ageing times of amorphous apatitic phases. Time taken to synthesize hydroxyapatite (which remained stable upon heat treatment at 900 °C for 1 h) reduced twelve folds (to 2 h) as compared to traditionally required times. The effects of increasing magnesium concentration in the precursors on particle size, surface area, phase-purity, agglomeration and thermal stability, were observed using scanning electron microscopy, BET surface area analysis, X-ray diffraction and photo acoustic Fourier transform infra-red spectroscopy. Porous agglomerates were obtained after a brief heat-treatment (1 h) at 900 °C. - Highlights: • Microwave irradiation of suspensions of calcium phosphates accelerated maturation. • Reactions took 2 h to complete as compared to 18 h required traditionally. • Magnesium contents higher than 1 wt.% lead to the presence of non-apatitic phases. • Agglomerates with micron and sub-micron porosity were obtained after heat-treatment.

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  2. 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.

  3. Friction stir welding of AZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    林三宝; 张华; 吴林; 冯吉才; 戴鸿滨

    2003-01-01

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

  4. Precision forging technologies for magnesium alloy bracket and wheel

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

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

    DEFF Research Database (Denmark)

    Rudnicki, M; Junge, Jette; Frølich, A;

    1990-01-01

    The placenta and the umbilical cord obtained from 18 women with pregnancy-induced hypertension were investigated by light microscopy. The umbilical artery was studied by electron microscopy. 10 placentae and umbilical cords from normal pregnancies served as controls. The study was performed...... fibrosis or intervillous fibrin. Ultrastructurally, the endothelial cells of the umbilical arteries from women with pregnancy-induced hypertension showed a significant increase in the amount of dilated endoplasmic reticulum and basal laminae thickness when all 18 cases were compared with the controls....... 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...

  6. Preliminary study of biodegradation of AZ31B magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    REN Yibin; HUANG Jingjing; ZHANG Bingchun; YANG Ke

    2007-01-01

    Magnesium alloys are potential to be developed as a new type of biodegradable implant material by use of their active corrosion behavior.Both in vitro and in vivo biodegradation properties of an AZ31B magnesium alloy were investigated in this work.The results showed that AZ31B alloy has a proper degradation rate and much lower hydrogen release in Hank's solution,with a degradation rate of about 0.3 mm/year and hydrogen release below 0.15mL/cm2.The animal implantation test showed that the AZ31B alloy could slowly biodegrade in femur of the rabbit and form calcium phosphate around the alloy sample,with the Ca/P ratio close to the natural bone.

  7. Properties of laser alloyed surface layers on magnesium base alloys

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-01-01

    The investigations have shown that laser surface alloying is a promising process to improve the wear and corrosion properties of magnesium base alloys without affecting the initial bulk properties like the low density. With an alloying element combination of aluminium and nickel the wear rate in the scratch test was reduced by 90% compared to untreated pure magnesium. Additionally the corrosion resistance was improved by laser alloying with this element combination. Because of distortion or crack formation in the case of large area treatments, the laser alloying should be limited to the treatment of smaller areas. In the near future this process could be an interesting alternative to surface coating or to a partially reinforcement with ceramic fibres or particles. (orig.)

  8. Microstructure analysis of magnesium alloy melted by laser irradiation

    Science.gov (United States)

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

    2005-12-01

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

  9. Affinity purification of native glycodelin from amniotic fluid for biological investigations and development of a glycodelin ELISA for clinical studies

    DEFF Research Database (Denmark)

    Sørensen, Steen; Myrhøj, Vibeke; Nguyen, Thanh Ha;

    2017-01-01

    INTRODUCTION: Glycodelin is a glycoprotein with different oligosaccharides that are responsible for its diverse biological functions in contraception and immunosuppression. Therefore, it is necessary to have access to adequate amounts of glycodelin with retained carbohydrate structure for functio...

  10. Fabrication of a Delaying Biodegradable Magnesium Alloy-Based Esophageal Stent via Coating Elastic Polymer

    Directory of Open Access Journals (Sweden)

    Tianwen Yuan

    2016-05-01

    Full Text Available Esophageal stent implantation can relieve esophageal stenosis and obstructions in benign esophageal strictures, and magnesium alloy stents are a good candidate because of biodegradation and biological safety. However, biodegradable esophageal stents show a poor corrosion resistance and a quick loss of mechanical support in vivo. In this study, we chose the elastic and biodegradable mixed polymer of Poly(ε-caprolactone (PCL and poly(trimethylene carbonate (PTMC as the coated membrane on magnesium alloy stents for fabricating a fully biodegradable esophageal stent, which showed an ability to delay the degradation time and maintain mechanical performance in the long term. After 48 repeated compressions, the mechanical testing demonstrated that the PCL-PTMC-coated magnesium stents possess good flexibility and elasticity, and could provide enough support against lesion compression when used in vivo. According to the in vitro degradation evaluation, the PCL-PTMC membrane coated on magnesium was a good material combination for biodegradable stents. During the in vivo evaluation, the proliferation of the smooth muscle cells showed no signs of cell toxicity. Histological examination revealed the inflammation scores at four weeks in the magnesium-(PCL-PTMC stent group were similar to those in the control group (p > 0.05. The α-smooth muscle actin layer in the media was thinner in the magnesium-(PCL-PTMC stent group than in the control group (p < 0.05. Both the epithelial and smooth muscle cell layers were significantly thinner in the magnesium-(PCL-PTMC stent group than in the control group. The stent insertion was feasible and provided reliable support for at least four weeks, without causing severe injury or collagen deposition. Thus, this stent provides a new stent for the treatment of benign esophageal stricture and a novel research path in the development of temporary stents in other cases of benign stricture.

  11. Investigating the role that the Southern Ocean biological pump plays in determining global ocean oxygen concentrations and deoxygenation

    OpenAIRE

    Keller, David; Oschlies, Andreas

    2013-01-01

    Global ocean circulation connects marine biogeochemical cycles through the long-range transport of nutrients and oxygen with the Southern Ocean (SO) acting as a water mass crossroads. The biological pump in the SO has been shown to play an important role in these dynamics and the amount of export production is known to have a large impact on remote deep ocean nutrients and dissolved inorganic carbon. However, the role that the SO biological pump plays in determining ocean oxygen concentration...

  12. Magnesium based degradable biomaterials: A review

    Science.gov (United States)

    Gu, Xue-Nan; Li, Shuang-Shuang; Li, Xiao-Ming; Fan, Yu-Bo

    2014-09-01

    Magnesium has been suggested as a revolutionary biodegradable metal for biomedical applications. The corrosion of magnesium, however, is too rapid to match the rates of tissue healing and, additionally, exhibits the localized corrosion mechanism. Thus it is necessary to control the corrosion behaviors of magnesium for their practical use. This paper comprehensively reviews the research progress on the development of representative magnesium based alloys, including Mg-Ca, Mg-Sr, Mg-Zn and Mg-REE alloy systems as well as the bulk metallic glass. The influence of alloying element on their microstructures, mechanical properties and corrosion behaviors is summarized. The mechanical and corrosion properties of wrought magnesium alloys are also discussed in comparison with those of cast alloys. Furthermore, this review also covers research carried out in the field of the degradable coatings on magnesium alloys for biomedical applications. Calcium phosphate and biodegradable polymer coatings are discussed based on different preparation techniques used. We also compare the effect of different coatings on the corrosion behaviors of magnesium alloys substrate.

  13. Magnesium 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....

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

    Science.gov (United States)

    Saliba, Daniel; Al-Ghoul, Mazen

    2016-11-01

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

  15. Magnesium and disturbances in carbohydrate metabolism.

    Science.gov (United States)

    Mooren, Frank C

    2015-09-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  17. In vitro Degradation and Biocompatibility of Ca-P Coated Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    XIAO Xing; ZHU Qing-san; SU Ying-chao; LI Guang-yu

    2013-01-01

    Calcium-phosphate compounds(Ca-P) coating was prepared on an Mg-Al alloy(AZ60).Biodegradation of Ca-P coated magnesium alloy was evaluated in simulated body fluid(SBF) by examining the changes in magnesium ion concentration and pH value,which indicated that the Ca-P coating on magnesium alloy strongly affected the corrosion of magnesium alloy.Osteoblast MC3T3-El cells were utilized to investigate the cellular cytocompatibility.The cytocompatibility was measured by carrying out a series of tests,such as cholecystokinin-octapeptide(CCK-8) test,alkaline phosphatase activity(ALP) test,cellular morphology of hematoxylin-eosin(HE) staining and the induction of apoptosis.It was found that the cell function showed better in the Ca-P coated Mg-alloy extract than in the uncoated magnesium alloy extract.In summary,the results indicate that the Ca-P coating can improve the corrosion resistance of magnesium alloy and elevate cellular proliferation and differentiation of osteoblast MC3T3-E1 cells.

  18. 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.

  19. 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.

  20. Preparation of biomimetic hydrophobic coatings on AZ91D magnesium alloy surface

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The hydrophobic coating has been a promising technology for improving surface performance. The surface performance of magnesium alloy has been limited in application. Furthermore, the hydrophobic of magnesium alloy is rarely investigated because magnesium alloy is an active metal alloy. In this paper, inspired by microstructure character of typical plant leaf surface such as lotus, the biomimetic hydrophobic coatings on AZ91D magnesium alloy surface were prepared by means of wet-chemical combining electroless. The samples were immersed into AgNO3 solution in wet-chemical method firstly. Then, biomimetic hydrophobic coatings were prepared by electroless after wet-method pretreatment. The microstructure was observed by SEM and the contact angles were measured by contact angle tester. The results indicated that the biomimetic hydrophobic coatings with uniform crystalline and dense structure could be obtained on AZ91D magnesium alloy surface. The results of contact angle revealed that the biomimetic nano-composite coatings were hydrophobic. The wet-chemical method treatment on the AZ91D magnesium alloy substrate provided a rough microstructure, thus improving adhesion of the coating and the substrate.

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

    Science.gov (United States)

    Cartagena-Rivera, Alexander X.

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

  2. 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.

  3. Biocorrosion rate and mechanism of metallic magnesium in model arterial environments

    Science.gov (United States)

    Bowen, Patrick K.

    A new paradigm in biomedical engineering calls for biologically active implants that are absorbed by the body over time. One popular application for this concept is in the engineering of endovascular stents that are delivered concurrently with balloon angioplasty. These devices enable the injured vessels to remain patent during healing, but are not needed for more than a few months after the procedure. Early studies of iron- and magnesium-based stents have concluded that magnesium is a potentially suitable base material for such a device; alloys can achieve acceptable mechanical properties and do not seem to harm the artery during degradation. Research done up to the onset of research contained in this dissertation, for the most part, failed to define realistic physiological corrosion mechanisms, and failed to correlate degradation rates between in vitro and in vivo environments. Six previously published works form the basis of this dissertation. The topics of these papers include (1) a method by which tensile testing may be applied to evaluate biomaterial degradation; (2) a suite of approaches that can be used to screen candidate absorbable magnesium biomaterials; (3) in vivo-in vitro environmental correlations based on mechanical behavior; (4) a similar correlation on the basis of penetration rate; (5) a mid-to-late stage physiological corrosion mechanism for magnesium in an arterial environment; and (6) the identification of corrosion products in degradable magnesium using transmission electron microscopy.

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

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

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

  5. [Effect of magnesium deficiency on photosynthetic physiology and triacylglyceride (TAG) accumulation of Chlorella vulgaris].

    Science.gov (United States)

    Wang, Shan; Zhao, Shu-Xin; Wei, Chang-Long; Yu, Shui-Yan; Shi, Ji-Ping; Zhang, Bao-Guo

    2014-04-01

    As an excellent biological resource, Chlorella has wide applications for production of biofuel, bioactive substances and water environment restoration. Therefore, it is very important to understand the photosynthetic physiology characteristics of Chlorella. Magnesium ions play an important role in the growth of microalgae, not only the central atom of chlorophyll, but also the cofactor of some key enzyme in the metabolic pathway. A laboratory study was conducted to evaluate the effects of magnesium deficiency on several photosynthetic and physiological parameters and the triacylglyceride (TAG) accumulation of the green alga, Chlorella vulgaris, in the photoautotrophic culture process. Chlorella vulgaris biomass, protein, chlorophyll a and chlorophyll b contents decreased by 20%, 43.96%, 27.52% and 28.07% in response to magnesium deficiency, while the total oil content increased by 19.60%. Moreover, magnesium deficiency decreased the maximal photochemical efficiency F(v)/F(m) by 22.54%, but increased the non-photochemical quenching parameters qN. Our results indicated the decline of chlorophyll caused by magnesium, which affected the photosynthesis efficiency, lead to the growth inhibition of Chlorella vulgaris and affected the protein synthesis and increased the triacylglyceride (TAG) accumulation.

  6. Boron Clusters as Highly Stable Magnesium-Battery Electrolytes**

    OpenAIRE

    Carter, Tyler J; Mohtadi, Rana; Arthur, Timothy S.; Mizuno, Fuminori; Zhang, Ruigang; Shirai, Soichi; Kampf, Jeff W.

    2014-01-01

    Boron clusters are proposed as a new concept for the design of magnesium-battery electrolytes that are magnesium-battery-compatible, highly stable, and noncorrosive. A novel carborane-based electrolyte incorporating an unprecedented magnesium-centered complex anion is reported and shown to perform well as a magnesium-battery electrolyte. This finding opens a new approach towards the design of electrolytes whose likelihood of meeting the challenging design targets for magnesium-battery electro...

  7. Biodegradable mesoporous calcium–magnesium silicate-polybutylene succinate scaffolds for osseous tissue engineering

    Directory of Open Access Journals (Sweden)

    Zhang X

    2015-10-01

    Full Text Available Xinxin Zhang,1,2,* Chi Zhang,3,* Wei Xu,1,* Biao Zhong,3 Feng Lin,3 Jian Zhang,3 Quanxiang Wang,4 Jiajin Ji,4 Jie Wei,4 Yang Zhang1 1TongRen Hospital, School of Medicine, Shanghai Jiao Tong University, 2Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 3Shanghai Sixth People’s Hospital, Shanghai Jiao Tong University, 4Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: The structural features of bone engineering scaffolds are expected to exhibit osteoinductive behavior and promote cell adhesion, proliferation, and differentiation. In the present study, we employed synthesized ordered mesoporous calcium–magnesium silicate (om-CMS and polybutylene succinate (PBSu to develop a novel scaffold with potential applications in osseous tissue engineering. The characteristics, in vitro bioactivity of om-CMS/PBSu scaffold, as well as the cellular responses of MC3T3-E1 cells to the composite were investigated. Our results showed that the om-CMS/PBSu scaffold possesses a large surface area and highly ordered channel pores, resulting in improved degradation and biocompatibility compared to the PBSu scaffold. Moreover, the om-CMS/PBSu scaffold exhibited significantly higher bioactivity and induced apatite formation on its surface after immersion in the simulated body fluid. In addition, the om-CMS/PBSu scaffold provided a high surface area for cell attachment and released Ca, Mg, and Si ions to stimulate osteoblast proliferation. The unique surface characteristics and higher biological efficacy of the om-CMS/PBSu scaffold suggest that it has great potential for being developed into a system that can be employed in osseous tissue engineering. Keywords: bone repair, polybutylene succinate, calcium–magnesium silicate, ordered mesoporous, proliferation

  8. Development of Magnesium-Insertion Positive Electrode for Rechargeable Magnesium Batteries

    Institute of Scientific and Technical Information of China (English)

    Huatang YUAN; Lifang JIAO; Jiansheng CAO; Xiusheng LIU; Ming ZHAO; Yongmei WANG

    2004-01-01

    Magnesium-based rechargeable batteries might be an interesting future alternative to lithium-based batteries. It is so far well known that Mg2+ ion insertion into ion-transfer hosts proceeds slowly compared with Li+, so it is necessary to realize fast Mg2+ transport in the host in addition to other requirements as practical cathode materials for magnesium batteries. Positive electrode materials based on inorganic transition-metal oxides, sulfides, and borides are the only ones used up to now to insert magnesium ions. In this paper, the available results of research on materials suitable as possible, for secondary magnesium batteries, are reviewed.

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

    Science.gov (United States)

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

    2014-03-01

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

  10. Buffer-regulated biocorrosion of pure magnesium.

    Science.gov (United States)

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

    2012-02-01

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

  11. A novel bench-scale column assay to investigate site-specific nitrification biokinetics in biological rapid sand filters

    DEFF Research Database (Denmark)

    Tatari, Karolina; Smets, Barth F.; Albrechtsen, Hans-Jørgen

    2013-01-01

    A bench-scale assay was developed to obtain site-specific nitrification biokinetic information from biological rapid sand filters employed in groundwater treatment. The experimental set-up uses granular material subsampled from a full-scale filter, packed in a column, and operated with controlled....../h could easily be determined at 7.5 g NH4+–N/m3 packed sand/h. This assay, with conditions reflecting full-scale observations, and where the biological activity is subject to minimal physical disturbance, provides a simple and fast, yet powerful tool to gain insight in nitrification kinetics in rapid sand...

  12. Report of biological investigations at the Los Medanos Waste Isolation Pilot Plant (WIPP) area of New Mexico during FY 1978

    Energy Technology Data Exchange (ETDEWEB)

    Best, T.L.; Neuhauser, S. (eds.)

    1980-03-01

    The US Department of Energy is considering the construction of a Waste Isolation Pilot Plant (WIPP) in Eddy County, NM. This location is approximately 40 km east of Carlsbad, NM. Biological studies during FY 1978 were concentrated within a 5-mi radius of drill hole ERDA 9. Additional study areas have been established at other sites in the vicinity, e.g., the Gnome site, the salt lakes and several stations along the Pecos River southward from Carlsbad, NM, to the dam at Red Bluff Reservoir in Texas. The precise locations of all study areas are presented and their biology discussed.

  13. Producing Magnesium Metallic Glass By Disintegrated Melt Deposition

    Science.gov (United States)

    Shanthi, M.; Gupta, M.; Jarfors, A. E. W.; Tan, M. J.

    2011-01-01

    Bulk metallic glasses are new class of engineering materials that exhibit high resistance to crystallization in the under cooled liquid state. The development of bulk metallic glasses of thickness 1cm or less has opened new doors for fundamental studies of both liquid state and glass transition previously not feasible in metallic materials. Moreover, bulk metallic glasses exhibit superior hardness, strength, specific strength, and elastic strain limit, along with good corrosion and wear resistance. Thus they are potential candidates in various sports, structural, engineering and medical applications. Among several BMGs investigated, magnesium-based BMGs have attracted considerable attention because of their low density and superior mechanical properties. The major drawback of this magnesium based BMGs is poor ductility. This can be overcome by the addition of ductile particles/reinforcement to the matrix. In this study, a new technique named disintegrated melt deposition technique was used to synthesize magnesium based BMGs. Rods of different sizes are cast using the current method. Mechanical characterization studies revealed that the amorphous rods produced by the current technique showed superior mechanical properties.

  14. Dietary intake of magnesium may modulate depression.

    Science.gov (United States)

    Yary, Teymoor; Aazami, Sanaz; Soleimannejad, Kourosh

    2013-03-01

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

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

    Science.gov (United States)

    Elmore, Amy R

    2003-01-01

    This report reviews the safety of Aluminum, Calcium, Lithium Magnesium, Lithium Magnesium Sodium, Magnesium Aluminum, Magnesium, Sodium Magnesium, and Zirconium Silicates, Magnesium Trisilicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite as used in cosmetic formulations. The common aspect of all these claylike ingredients is that they contain silicon, oxygen, and one or more metals. Many silicates occur naturally and are mined; yet others are produced synthetically. Typical cosmetic uses of silicates include abrasive, opacifying agent, viscosity-increasing agent, anticaking agent, emulsion stabilizer, binder, and suspending agent. Clay silicates (silicates containing water in their structure) primarily function as adsorbents, opacifiers, and viscosity-increasing agents. Pyrophyllite is also used as a colorant. The International Agency for Research on Cancer has ruled Attapulgite fibers >5 microm as possibly carcinogenic to humans, but fibers mining and processing of Aluminum Silicate, Calcium Silicate, Zirconium Silicate, Fuller's Earth, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite. The Cosmetic Ingredient Review (CIR. The Cosmetic Ingredient Review (CIR) Expert Panel concluded that the extensive pulmonary damage in humans was the result of direct occupational inhalation of the dusts and noted that lesions seen in animals were affected by particle size, fiber length, and concentration. The Panel considers that most of the formulations are not respirable and of the preparations that are respirable, the concentration of the ingredient is very low. Even so, the Panel considered that any spray containing these solids should be formulated to minimize their inhalation. With this admonition to the cosmetics industry, the CIR Expert Panel concluded that these ingredients are safe as currently used in cosmetic formulations. The Panel did note that the cosmetic ingredient, Talc, is a hydrated magnesium silicate

  16. The Investigation and Comparison of Furfural Removal from Wastewater using Cyclic Biological Reactor (CBR and Fusarium Culmorum Granules

    Directory of Open Access Journals (Sweden)

    Mostafa Leili

    2013-09-01

    Conclusion: Under different operating conditions of biological systems, high removal efficiency of furfural was observed, but CBR in comparison with Fusarium culmorum granules reached the optimum and desired removal efficiency in shorter time. Therefore, these systems can be developed and replaced with chemical methods to treat furfural containing wastewater.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  18. An Investigation into Students' Difficulties in Numerical Problem Solving Questions in High School Biology Using a Numeracy Framework

    Science.gov (United States)

    Scott, Fraser J.

    2016-01-01

    The "mathematics problem" is a well-known source of difficulty for students attempting numerical problem solving questions in the context of science education. This paper illuminates this problem from a biology education perspective by invoking Hogan's numeracy framework. In doing so, this study has revealed that the contextualisation of…

  19. TRICHODERMA VIRIDE PERS. – EXPERIMENTAL MODEL FOR BIOLOGICAL AND BIOTECHNOLOGICAL INVESTIGATIONS OF MYCROMYCETA WITH IMPORTANCE IN OBTAINING PLANT PROTECTION BIOPRODUCTS

    Directory of Open Access Journals (Sweden)

    SESAN TATIANA EUGENIA

    2010-12-01

    Full Text Available The technological process for obtaining plant protection bioproducts contains 2 main phases: (i biomass biosynthesis of microorganisms in a culture medium, available for industrialization and (ii biomass conditioning of microorganism, the antagonistic micromycetes, respectively. For this type of activities it is essential to establish biological development parameters: (i the optimum composition of the liquid culture medium for development of the fungus under aerobiotic conditions and (ii the optimal parameters of biosynthesis in the studied medium. The biomass biosynthesis technology is discontinuous, of cascade type, and develops several phases: (1 preparing of the laboratory inoculum, (2 preparing of the fungal pure culture in Erlenmeyer bottles, (3 industrial (simulated multiplication in the aired and agitated liquid medium.This paper presents some experimental aspects referring to: 1 – Characterization of the biologically active T. viride isolates, establishing and verifying of their biological thresholds; 2 – Evaluation and experimental verifying of the mass multiplication ability of antagonistic T. viride fungi on the culture media in order to select the optimum industrial culture substrate (medium; 3 – Biochimical characterization of T. viride isolates by electrophoretic analysis of their protein profile; 4 – Evaluation of the T. viride biological activity of T. viride isolates against phytopathogenic fungi with high practical importance: Fusarium graminearum Schwabe (T. Gibberella zeae (Schwein. Petch, F. culmorum (W. G. Sm. Sacc., Pythium ultimum Trow, Botrytis cinerea Pers., Sclerotinia sclerotiorum (Lib. de Bary, Alternaria spp. [A. alternata (Fr. Keissl., Alternaria radicina Meier, Drechsler and E. D. Eddy (Stemphylium radicinum (Meier, Drechsler and E. D. Eddy Neerg.] etc.; 5 – Processing of technological scheme for obtaining plant protection preparates based on biologically active isolates of T. viride.

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

    Science.gov (United States)

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

    2012-06-01

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

  1. A pilot study on the effects of magnesium supplementation with high and low habitual dietary magnesium intake on resting and recovery from aerobic and resistance exercise and systolic blood pressure.

    Science.gov (United States)

    Kass, Lindsy S; Skinner, Philip; Poeira, Filipe

    2013-01-01

    The effects of magnesium supplementation on blood pressure (BP) have been studied for over 25 years and results have been inconsistent. Blood pressure reductions in randomized studies have varied from 12 mmHg reductions to no reduction. The objective of this pilot intervention was to investigate the effect of magnesium supplementation on systolic blood pressure whilst resting and during recovery from aerobic and resistance exercise and on performance. A further objective was to see whether the effect of a high vs low habitual dietary magnesium intake affected these results. Sixteen male volunteers were randomly assigned to either a 300 mg·d(-1) magnesium oxide supplementation (MO) or a control group (CG) for 14 days. Resting blood pressure (BP) and heart rate (HR) were measured before subjects performed a maximal 30 minute cycle, immediately followed by three x 5 second isometric bench press, both at baseline and after the intervention. Blood pressure and heart rate were recorded immediately post exercise and after five minutes recovery. A 3 day food diary was recorded for all subjects to measure dietary magnesium intake. At the end of the intervention, the supplemented group, had a reduction in mean resting systolic BP by 8.9 mmHg (115.125 ± 9.46 mmHg, p = 0.01) and post exercise by 13 mmHg (122.625 ± 9. 88 mmHg, p = 0.01). Recovery BP was 11.9 mmHg lower in the intervention group compared to control (p = 0.006) and HR decreased by 7 beats per minute in the experimental group (69.0 ± 11.6 bpm, p = 0. 02). Performance indicators did not change within and between the groups. Habitual dietary magnesium intake affected both resting and post exercise systolic BP and the subsequent effect of the magnesium supplementation. These results have an implication in a health setting and for health and exercise but not performance. Key pointsMagnesium supplementation will have an effect on resting and recovery systolic blood pressure with aerobic exercise.Magnesium

  2. 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...

  3. 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.

  4. Impact of Testosterone, Zinc, Calcium and Magnesium Concentrations on Sperm Parameters in Subfertile Men

    Science.gov (United States)

    Aydemir, Birsen; Kiziler, Ali Riza; Onaran, Ilhan; Alici, Bülent; Özkara, Hamdi; Akyolcu, Mehmet Can

    2007-04-01

    To investigate the impact of testosterone, zinc, calcium and magnesium concentrations in serum and seminal plasma on sperm parameters. There were significant decrease in sperm parameters, serum and seminal plasma zinc levels in subfertile males. It indicates zinc has a essential role in male infertility; the determination the level of zinc during infertility investigation is recommended.

  5. Study of Some Dielectric Properties of Suspensions of Magnesium Particles in Mineral Oil

    Science.gov (United States)

    Altshuller, Aubrey P

    1954-01-01

    The variation of dielectric constant has been measured as a function of the concentration of magnesium particles; the shape, size, and degree of oxidation of the particles; the temperature; and the frequency of oscillation. The variation of dielectric constant and settling rate was investigated as a function of time. Also investigated were the effects of particle concentration, shape and time on dielectric losses.

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

    Science.gov (United States)

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

    1997-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Mi-Kyeong Choi

    Full Text Available Magnesium is known to lower the risk of cardiovascular disease. However, studies on its relationship with hypertension, a single and common cause of various chronic diseases, are limited and their findings are not consistent. The purpose of the present study is to identify the relationship between magnesium intake and high blood pressure (HBP risk in Koreans.This research is a cross-sectional study based on the 2007~2009 Korean National Health and Nutritional Examination Survey data. This study investigated 11,685 adults aged over 20 to examine their general characteristics, anthropometry and blood pressure. Daily magnesium intake was analyzed using the 24-hour dietary recall method. To calculate the odds ratio (OR of HBP risk (130/85 mmHg or over according to the quartile of magnesium intake (mg/1000 kcal together with its 95% confidence interval (CI, multivariable logistic regression analysis was performed.No significant association between dietary magnesium intake and the risk of HBP was found. In obese women, particularly, after adjusting relevant factors, the adjusted odds ratio of HBP prevalence in the highest magnesium intake quartile was 0.40 compared with the lowest magnesium intake quartile (95% CI = 0.25~0.63, P for trend = 0.0014. Women, especially obese women, were found to have a negative relationship of magnesium intake with HBP.The present results indicate that sufficient magnesium intake could be useful in decreasing the high blood pressure risk of obese women.

  8. X-ray phase microtomography with a single grating for high-throughput investigations of biological tissue.

    Science.gov (United States)

    Zdora, Marie-Christine; Vila-Comamala, Joan; Schulz, Georg; Khimchenko, Anna; Hipp, Alexander; Cook, Andrew C; Dilg, Daniel; David, Christian; Grünzweig, Christian; Rau, Christoph; Thibault, Pierre; Zanette, Irene

    2017-02-01

    The high-throughput 3D visualisation of biological specimens is essential for studying diseases and developmental disorders. It requires imaging methods that deliver high-contrast, high-resolution volumetric information at short sample preparation and acquisition times. Here we show that X-ray phase-contrast tomography using a single grating can provide a powerful alternative to commonly employed techniques, such as high-resolution episcopic microscopy (HREM). We present the phase tomography of a mouse embryo in paraffin obtained with an X-ray single-grating interferometer at I13-2 Beamline at Diamond Light Source and discuss the results in comparison with HREM measurements. The excellent contrast and quantitative density information achieved non-destructively and without staining using a simple, robust setup make X-ray single-grating interferometry an optimum candidate for high-throughput imaging of biological specimens as an alternative for existing methods like HREM.

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

    Science.gov (United States)

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

    2015-04-01

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

  10. Magnesium status and the physical performance of volleyball players: effects of magnesium supplementation.

    Science.gov (United States)

    Setaro, Luciana; Santos-Silva, Paulo Roberto; Nakano, Eduardo Yoshio; Sales, Cristiane Hermes; Nunes, Newton; Greve, Júlia Maria; Colli, Célia

    2014-01-01

    The aim of this study was to test the hypothesis that magnesium supplementation influences the physical performance of volleyball players, as the efficacy of this approach remains questionable. Twenty-five professional male volleyball players were assigned randomly to experimental (350 mg Mg · d(-1), 4 weeks) and control groups (500 mg maltodextrin · d(-1), 4 weeks) maintaining inter-group homogeneity of urinary magnesium. Erythrocyte, plasma and urinary magnesium levels, plasma creatine kinase activity, lactate production, maximal oxygen uptake (VO2 max) and plyometric (squat jump, countermovement jump, countermovement jump with arm swing) and isokinetic (peak torque, potency and total work) performances were evaluated before (T0) and after (T1) supplementation. Levels of erythrocyte and urinary magnesium and creatine kinase activity and VO2 max remained within normal ranges in both groups. Plasma magnesium decreased significantly only within the experimental group. Significant decreases in lactate production and significant increases (of up to 3 cm) in countermovement jump and countermovement jump with arm swing values were detected in the experimental group following magnesium supplementation, but not in the control group at T1. It is concluded that magnesium supplementation improved alactic anaerobic metabolism, even though the players were not magnesium-deficient.

  11. Proficient magnesium nanoferrites: synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-15

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

  12. Investigations in space-related molecular biology. [cryo-electron microscopic and diffraction studies on terrestrial and extraterrestrial specimens

    Science.gov (United States)

    Fernandez-Moran, H.; Pritzker, A. N.

    1974-01-01

    Improved instrumentation and preparation techniques for high resolution, high voltage cryo-electron microscopic and diffraction studies on terrestrial and extraterrestrial specimens are reported. Computer correlated ultrastructural and biochemical work on hydrated and dried cell membranes and related biological systems provided information on membrane organization, ice crystal formation and ordered water, RNA virus linked to cancer, lunar rock samples, and organometallic superconducting compounds. Apollo 11, 12, 14, and 15 specimens were analyzed

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

    Science.gov (United States)

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

    2014-11-01

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

  14. A novel and simple fluorescence probe for detecting main group magnesium ion in HeLa cells and Arabidopsis.

    Science.gov (United States)

    Yu, Tingting; Sun, Ping; Hu, Yijie; Ji, Yinggang; Zhou, Hongping; Zhang, Baowei; Tian, Yupeng; Wu, Jieying

    2016-12-15

    A simple-molecule fluorescence probe L has been designed, synthesized and characterized, which shows high selectivity and sensitivity for the main group magnesium ion through fluorescence "turn-on" response in ethanol solution, and no interference from calcium ion in particular. Detection limit of probe L is 1.47×10(-6) M and the rapid response could reach about 15-20s. The recognition mechanism has been established by fluorescence spectra, (1)H NMR study. Moreover, probe L presents a great photostability, low toxicity and cellular permeability, then we have carried out fluorescent bio-imaging of the probe L for magnesium ions in HeLa cells, which showed that probe L could be utilized to detect the intracellular magnesium ion. Furthermore, it is successfully used as a magnesium ion developer in plant tissues, which shows that it not only can be well tracking the transport of magnesium ion but also make a corresponding fluorescence response to different concentrations magnesium ion. These results would make this probe a great potential application for detecting Mg(2+) in biological system.

  15. Phosphate conversion coating reduces the degradation rate and suppresses side effects of metallic magnesium implants in an animal model.

    Science.gov (United States)

    Rahim, Muhammad Imran; Tavares, Ana; Evertz, Florian; Kieke, Marc; Seitz, Jan-Marten; Eifler, Rainer; Weizbauer, Andreas; Willbold, Elmar; Jürgen Maier, Hans; Glasmacher, Birgit; Behrens, Peter; Hauser, Hansjörg; Mueller, Peter P

    2016-05-06

    Magnesium alloys have promising mechanical and biological properties for the development of degradable implants. However, rapid implant corrosion and gas accumulations in tissue impede clinical applications. With time, the implant degradation rate is reduced by a highly biocompatible, phosphate-containing corrosion layer. To circumvent initial side effects after implantation it was attempted to develop a simple in vitro procedure to generate a similarly protective phosphate corrosion layer. To this end magnesium samples were pre-incubated in phosphate solutions. The resulting coating was well adherent during routine handling procedures. It completely suppressed the initial burst of corrosion and it reduced the average in vitro magnesium degradation rate over 56 days almost two-fold. In a small animal model phosphate coatings on magnesium implants were highly biocompatible and abrogated the appearance of gas cavities in the tissue. After implantation, the phosphate coating was replaced by a layer with an elemental composition that was highly similar to the corrosion layer that had formed on plain magnesium implants. The data demonstrate that a simple pre-treatment could improve clinically relevant properties of magnesium-based implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

  16. A review: Hot topics on magnesium technology in China

    Institute of Scientific and Technical Information of China (English)

    Zhen-hua CHEN; Ji-hua CHEN

    2008-01-01

    Magnesium alloys have wide applications in automobiles, aerospace and so on due to many advan-tages, while a number of undesirable properties including poor corrosion resistance, inferior creep resistance and bad plastic processing ability have hindered their applica-tions. Creep-resistant magnesium alloy design, plastic processing of magnesium alloys and rapid solidification processing of magnesium alloys have become the hot topics in magnesium technology. Other than these, surface modification as well as laser beam welding are also involved. The research progress and development in mag-nesium technology in China are reviewed in the paper.

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

    Science.gov (United States)

    Deacon, Jeffrey R.; Stephens, Verlin C.

    1996-01-01

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

  18. Interfacial chemistry of organic conversion film on AZ61 magnesium alloy surface

    Science.gov (United States)

    Yang, Xu; Pan, Fusheng; Zhang, Dingfei

    2008-12-01

    The anodic electrochemical behavior of AZ61 magnesium alloy in sodium hydroxide medium in the absence and presence of p-nitro-benzene-azo-resorcinol (PNBAR) was studied using electrochemical techniques. In the presence of PNBAR, organic conversion film formed on the surface of magnesium alloy. The nature of chemical mechanisms, bonds, and structures at the interface of PNBAR/magnesium alloy was investigated by using energy dispersive spectrometer (EDS) analysis and Fourier transform infrared spectroscopy. An in situ electrochemical deposition was evidenced to produce a corrosion protective barrier by the formation of organic conversion film of magnesium-PNBAR complex and to enhance film adhesion by the covalent bonds of Mg sbnd O sbnd N linkage. The linear sweep voltammetry experiments and the score tests were used to investigate the adhesion and evaluate the potential of corrosion resistance of organic conversion film. The results indicated the corrosion resistance of magnesium alloy was improved, the organic conversion film showed excellent adhesion not only to the substrate but also to the outer paint coatings.

  19. Hydrogen desorption kinetics of MgH2 synthesized from modified waste magnesium

    Science.gov (United States)

    Kantürk Figen, Aysel; Coşkuner, Bilge; Pişkin, Sabriye

    2014-09-01

    In the present study, hydrogen desorption properties of magnesium hydride (MgH2) synthesized from modified waste magnesium chips (WMC) were investigated. MgH2 was synthesized by hydrogenation of modified waste magnesium at 320 °C for 90 min under a pressure of 6 × 106 Pa. The modified waste magnesium was prepared by mixing waste magnesium with tetrahydrofuran (THF) and NaCl additions, applying mechanical milling. Next, it was investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) techniques in order to characterize its structural properties. Hydrogen desorption properties were determined by differential scanning calorimetry (DSC) under nitrogen atmosphere at different heating rates (5, 10, and 15 °C/min). Doyle and Kissenger non-isothermal kinetic models were applied to calculate energy (E a ) values, which were found equal to 254.68 kJ/mol and 255.88 kJ/mol, respectively.

  20. Hydrogen Adsorption onto Magnesium Palladium and Magnesium Palladium Niobium Multilayer Thin Films

    Science.gov (United States)

    Steinmetz, Christian; Hettinger, Jeffrey; Dobbins, Tabbetha

    2013-03-01

    We report on the synthesis and characterization of magnesium palladium and magnesium niobium multilayer thin films as a possible reversible hydrogen storage material. The multilayer thin films are characterized by x-ray diffraction (XRD) and x-ray reflectivity (XRR) before and after hydrogen uptake. This study examines the optimal thickness of the magnesium film which would allow the diffusion of hydrogen to form magnesium hydride (MgH2). Thin barriers of palladium and niobium permit hydrogen to permeate while acting as a diffusion barrier to oxygen. Multilayer thin films are grown with various magnesium thicknesses via magnetron sputtering on a sapphire substrate. Thicknesses of Mg, MgH2, Pd, and Nb are reported. Likewise, interfacial roughness attributable to hydrogenation and dehydrogenation cycling measured using XRR are reported.

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

    CERN Document Server

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    F. Živić

    2014-03-01

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

  3. Coating Prospects in Corrosion Prevention of Aluminized Steel and Its Coupling with Magnesium

    Science.gov (United States)

    Sun, Fuyan

    In this study, a plasma electrolytic oxidation (PEO) process was used to form oxide coating on aluminized steel, heated aluminized steel and magnesium. A potentiodynamic polarization corrosion test was employed to investigate the general corrosion properties. Galvanic corrosion of steel samples and magnesium samples was studied by zero resistance ammeter (ZRA) tests and boiling tests. Scanning electron microscopy (SEM) and EDS were used to investigate the coating microstructure and the coating/substrate interface. In general, the PEO coatings on all three substrate can help prevent general corrosion. 6-min coated magnesium with unipolar current mode performs best in most galvanic couplings for preventing both general corrosion and galvanic corrosion. Factors which could influence galvanic corrosion behaviors of tested samples were discussed based on area ratios of anode/cathode and cell potential driving force during the ZRA corrosion tests and boiling tests.

  4. [Impact of drinking water calcium and magnesium levels on morbidity in the Omsk Region].

    Science.gov (United States)

    Erofeev, Iu V; Neskin, T A; Turchaninov, D V

    2006-01-01

    Drinking water calcium and magnesium levels were examined for impact on morbidity in a model rural area of a West Siberian region. It was ascertained that there were negative correlations between the water levels of the above elements and the incidence of respiratory, gastrointestinal, and locomotor diseases and positive correlations between the concentrations of calcium and magnesium and the incidence of nervous, urogenital, and eye diseases. It is concluded that by adjusting the findings, the medical care availability factor should be taken into account in the investigations using the health indices calculated on the data from official medical accounts. This investigation has shown the estimation of the drinking water levels of calcium and magnesium as a significant hygienic problem for a model region.

  5. Magnesium and type 2 diabetes

    Institute of Scientific and Technical Information of China (English)

    Mario; Barbagallo; Ligia; J; Dominguez

    2015-01-01

    Type 2 diabetes is frequently associated with both extracellular and intracellular magnesium(Mg) deficits. A chronic latent Mg deficit or an overt clinical hypomagnesemia is common in patients with type 2 diabetes, especially in those with poorly controlled glycemic profiles. Insulinand glucose are important regulators of Mg metabolism. Intracellular Mg plays a key role in regulating insulin action, insulin-mediated-glucose-uptake and vascular tone. Reduced intracellular Mg concentrations result in a defective tyrosine-kinase activity, postreceptorial impairment in insulin action and worsening of insulin resistance in diabetic patients. A low Mg intake and an increased Mg urinary loss appear the most important mechanisms that may favor Mg depletion in patients with type 2 diabetes. Low dietary Mg intake has been related to the development of type 2 diabetes and metabolic syndrome. Benefits of Mg supplementation on metabolic profiles in diabetic patients have been found in most, but not all clinical studies and larger prospective studies are needed to support the potential role of dietary Mg supplementation as a possible public health strategy in diabetes risk. The aim of this review is to revise current evidence on the mechanisms of Mg deficiency in diabetes and on the possible role of Mg supplementation in the prevention and management of the disease.

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

  7. 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.

  8. 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.

  9. Outcomes of a 2-year investigation on enhanced biological nutrients removal and trace organics elimination in membrane bioreactor (MBR).

    Science.gov (United States)

    Lesjean, B; Gnirss, R; Buisson, H; Keller, S; Tazi-Pain, A; Luck, F

    2005-01-01

    Two configurations of membrane bioreactors were identified to achieve enhanced biological phosphorus and nitrogen removal, and assessed over more than two years with two parallel pilot plants of 2m3 each. Both configurations included an anaerobic zone ahead of the biological reactor, and differed by the position of the anoxic zone: standard pre-denitrification, or post-denitrification without dosing of carbon source. Both configurations achieved improved phosphorus removal. The goal of 50 microgP/L in the effluent could be consistently achieved with two types of municipal wastewater, the second site requiring a low dose of ferric salt ferric salt eliminated for 10 mg BOD5 in the influent. The post-denitrification configuration enabled a very good elimination of nitrogen. Daily nitrate concentration as low as 1 mgN/L could be monitored in the effluent in some periods. The denitrification rates, greater than those expected for endogenous denitrification, could be accounted for by the use of the glycogene pool, internally stored by the denitrifying microorganisms in the anaerobic zone. Pharmaceuticals residues and steroids were regularly monitored on the two parallel MBR pilot plants during the length of the trials, and compared with the performance of the Berlin-Ruhleben WWTP. Although some compounds such as carbamazepine were persistent through all the systems, most of the compounds could be better removed by the MBR plants. The influence of temperature, sludge age and compound concentration could be shown, as well as the significance of biological mechanisms in the removal of trace organic compounds.

  10. Investigating on the Correlation Between Some Biological Activities of Marine Sponge-Associated Bacteria Extracts and Isolated Diketopiperazines.

    Science.gov (United States)

    Abd El-Hady, Faten K; Fayad, Walid; Iodice, Carmine; El-Shahid, Zeinab A; Abdel-Aziz, Mohamed S; Crudele, Egle; Tommonaro, Giuseppina

    2017-01-01

    Marine organisms have been considered as the richest sources of novel bioactive metabolites, which can be used for pharmaceutical purposes. In the last years, the interest for marine microorganisms has grown for their enormous biodiversity and for the evidence that many novel compounds isolated from marine invertebrates are really synthesized by their associated bacteria. Nevertheless, the discovery of a chemical communication Quorum sensing (QS) between bacterial cells and between bacteria and host has gained the researchers to expand the aim of their study toward the role of bacteria associated with marine invertebrates, such as marine sponge. In the present paper, we report the evaluation of biological activities of different extracts of bacteria Vibrio sp. and Bacillus sp. associated with marine sponges Dysidea avara and Ircinia variabilis, respectively. Moreover, we evaluated the biological activities of some diketopiperazines (DKPs), previously isolated, and able to activate QS mechanism. The results showed that all extracts, fractions, and DKPs showed low scavenging activity against DPPH and superoxide anion, low cytotoxic and anti-tyrosinase activities, but no antimicrobial and acetylcholinesterase inhibitory activities. One DKP [cyclo-(trans-4-hydroxy-L-prolyl-L-leucine)] has the highest α-glucosidase inhibitory activity even than the standard acarbose.

  11. Is synthetic biology mechanical biology?

    Science.gov (United States)

    Holm, Sune

    2015-12-01

    A widespread and influential characterization of synthetic biology emphasizes that synthetic biology is the application of engineering principles to living systems. Furthermore, there is a strong tendency to express the engineering approach to organisms in terms of what seems to be an ontological claim: organisms are machines. In the paper I investigate the ontological and heuristic significance of the machine analogy in synthetic biology. I argue that the use of the machine analogy and the aim of producing rationally designed organisms does not necessarily imply a commitment to mechanical biology. The ideal of applying engineering principles to biology is best understood as expressing recognition of the machine-unlikeness of natural organisms and the limits of human cognition. The paper suggests an interpretation of the identification of organisms with machines in synthetic biology according to which it expresses a strategy for representing, understanding, and constructing living systems that are more machine-like than natural organisms.

  12. Hydrogen storage property of sandwiched magnesium hydride nanoparticle thin film

    Energy Technology Data Exchange (ETDEWEB)

    Barcelo, Steven; Rogers, Matthew; Grigoropoulos, Costas P.; Mao, Samuel S. [Lawrence Berkeley National Laboratory and Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720 (United States)

    2010-07-15

    Hydrogen sorption property of magnesium (Mg) in the form of sandwiched Pd/Mg/Pd films is investigated. Pulsed laser deposition method was applied to deposit the samples consisting of films of nanoparticles. The enthalpy of formation of MgH{sub 2} was found to be -68 kJ/mol H{sub 2} for films with nanoparticle size on the order of 50 nm, which is smaller than the value for bulk MgH{sub 2} and may be explained by the concept of excess volume. (author)

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

    Science.gov (United States)

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

    2016-12-01

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

  14. Correlation of recalescence with grain refinement of magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The grain refinement of Mg-Al based alloys with carbon inoculation was investigated by a computer-aided cooling curve analysis(CA-CCA)system.The results show that carbon inoculation decreases the main parameters of the recalescence regime during the initial stage of solidification.These parameters include the recalescence undercooling(△θrec),duration of recalescence (trec),and liquid peak parameter(LPP)which is firstly introduced into magnesium alloys.The resultant grain size decreases with increasing nucleation temperature(θn)and decreasing values of △θrec,trec and LPE

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

  17. Using Affinity Chromatography to Investigate Novel Protein-Protein Interactions in an Undergraduate Cell and Molecular Biology Lab Course

    Science.gov (United States)

    Belanger, Kenneth D.

    2009-01-01

    Inquiry-driven lab exercises require students to think carefully about a question, carry out an investigation of that question, and critically analyze the results of their investigation. Here, we describe the implementation and assessment of an inquiry-based laboratory exercise in which students obtain and analyze novel data that contribute to our…

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

    NARCIS (Netherlands)

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

    1990-01-01

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

  19. Decreased magnesium level and membrane potential of glaucoma patients

    Directory of Open Access Journals (Sweden)

    Johnkennedy Nnodim

    2016-08-01

    The result probably suggests, that decrease in magnesium aggravates glaucoma while decrease in membrane potential could cause poor energy transmission and hence affect ocular blood flow. Hence, decreased magnesium and membrane potential levels contributes greatly to glaucoma.

  20. Magnesium diboride: one year on

    Energy Technology Data Exchange (ETDEWEB)

    Canfield, Paul [Iowa State University (United States); Ames Laboratory (United States); Bud' ko, Sergey L. [Ames Laboratory (United States)

    2002-01-01

    Last January physicists discovered that an innocuous compound that had been sitting on the shelf for decades was, in fact, a record-breaking intermetallic superconductor. At the end of 2000 superconductivity in metal alloys and compounds appeared to remain trapped by a glass ceiling. Over the previous 10 years the temperature at which certain oxide-based compounds - such as bismuth strontium calcium copper oxide and mercury barium calcium copper oxide - lost their resistance to electric current had soared to well over 100 K. Meanwhile, the transition temperature, T{sub c}, for carbon-based materials, including alkali-doped carbon-60 compounds, had risen close to the boiling point of liquid nitrogen (77 K). During the same period, however, the superconducting transition temperature of intermetallic compounds (materials made solely of metals and metal-like elements) remained close to 20 K - as it had been since the mid-1960s. By February 2001 everything had totally changed. It was as if a firecracker had gone off in the tidy little ant hill of superconductivity research. For the first few months of 2001, groups all over the world raced to understand the properties of a new intermetallic superconductor. The substance that everyone was scrambling to buy or make, the substance that was causing this grand commotion, was magnesium diboride (MgB{sub 2}). This seemingly innocuous binary compound, which had been present in many labs for over half a century, had been discovered to superconduct just below 40 K. Even though we already know an amazing amount about MgB{sub 2}, our knowledge of superconductivity in this compound is only one year old. There is therefore the very real potential to improve its critical properties. In a similar vein, it is almost certain that our understanding of this extreme example of intermetallic superconductivity will greatly improve over the next few years and may even reveal other extreme superconductors. (U.K.)

  1. 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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  3. 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.

  4. 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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

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

    Science.gov (United States)

    Lee, Seung-Tae

    2009-08-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

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

  9. Effects of rare earths on the microarc oxidation of a magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    LI Jianzhong; TIAN Yanwen; CUI Zuoxing; HUANG Zhenqi

    2008-01-01

    The effects of rate earths on the properties of the microarc oxidation (MAO) coating on a magnesium alloy were investigated by means of scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDS),and electrochemistry methods.The results show that a nice and compact MAO coating was successfully obtained when the magnesium alloy was treated in nitrate solutions as the pre-treatment of MAO.However,the MAO was not successfully completed for the silicate electrolytes with the addition of rare earths.After the magnesium alloy being treated by rare earth nitrate,the obtained MAO coating has advantages such as uniform distribution of thickness,improved corrosion resistance,and nice-uniform surface,as compared with the untreated magnesium alloy.In addition,the time of non-ESP,the voltage and current density of the MAO process obviously decrease.Cerium oxide doped on the surface of the magnesium alloy can significantly improve the corrosion resistance of the MAO coating and decrease the current density of the MAO process,as compared with lanthanum oxide,whereas the doped rare earths have no significant effect on the components of the MAO coating.

  10. Simulating Biological and Non-Biological Motion

    Science.gov (United States)

    Bruzzo, Angela; Gesierich, Benno; Wohlschlager, Andreas

    2008-01-01

    It is widely accepted that the brain processes biological and non-biological movements in distinct neural circuits. Biological motion, in contrast to non-biological motion, refers to active movements of living beings. Aim of our experiment was to investigate the mechanisms underlying mental simulation of these two movement types. Subjects had to…

  11. Ballistic Evaluation of Magnesium Alloy AZ31B

    Science.gov (United States)

    2007-04-01

    S. Burkins, and William A. Gooch Weapons and Materials Research Directorate, ARL Richard D. DeLorme Magnesium Elektron North America, Inc...ballistic properties. In order to fill this gap, the U.S. Army Research Laboratory (ARL) and Magnesium Elektron North America (MENA), Inc., conducted a...plate (H24 condition). The magnesium plate was alloyed, cast, rolled, thermally treated and tensile tested by Magnesium Elektron North America (MENA

  12. Long-term excessive magnesium supplementation is deleterious whereas suboptimal supply is beneficial for bones in rats.

    Science.gov (United States)

    Riond, J L; Hartmann, P; Steiner, P; Ursprung, R; Wanner, M; Forrer, R; Spichiger, U E; Thomsen, J S; Mosekilde, L

    2000-12-01

    The long-term effects of a suboptimal magnesium supply inducing a marginal or moderate deficiency or of an excessive magnesium supplementation corresponding to a basal diet with a high pharmacological intake were investigated in 36 growing Sprague-Dawley female rats. The rats were randomly divided in three groups and received a purified diet with 7 g calcium, 5 g phosphorus and either 0.2, 0.5 or 2 g magnesium per kg diet for 7 months. At the end of the trial, plasma and erythrocyte total magnesium concentrations were significantly lower in the magnesium-deficient group than in the respective control group. Serum concentrations of 1,25-dihydroxyvitamin D, PTH and IGF-I and the length of the right humeri were not affected by the dietary treatment. The volumes corrected for body weight, the medio-lateral diameters and the ratios dry weight/length of the right humeri, and the dry weight corrected for body weight of the left tibiae and of the right humeri were significantly smaller in the magnesium-supplemented group than in the two other groups. The magnesium contents of the left tibiae and of the first lumbar vertebrae were significantly lower in the magnesium-deficient group than in the two other groups. In the right femora, dual energy X-ray absorptiometry revealed significantly smaller areas in the proximal part and significantly smaller mineral contents in the second proximal quarter in the magnesium-supplemented group compared with the two other groups. Peripheral quantitative computer tomography of the right humeri revealed in the cortex significantly larger values for the relative area, mineral content, mineral density and thickness in the magnesium-deficient group compared with the control group. The maximum point of the load-deformation curve was significantly reduced in the fifth lumbar vertebrae and in the proximal femoral metaphyses of the magnesium-supplemented group. These results indicate that the long-term suboptimal magnesium supply improved some of

  13. Microwave assisted synthesis and characterization of magnesium substituted calcium phosphate bioceramics.

    Science.gov (United States)

    Khan, Nida Iqbal; Ijaz, Kashif; Zahid, Muniza; Khan, Abdul S; Abdul Kadir, Mohammed Rafiq; Hussain, Rafaqat; Anis-Ur-Rehman; Darr, Jawwad A; Ihtesham-Ur-Rehman; Chaudhry, Aqif A

    2015-11-01

    Hydroxyapatite is used extensively in hard tissue repair due to its biocompatibility and similarity to biological apatite, the mineral component of bone. It differs subtly in composition from biological apatite which contains other ions such as magnesium, zinc, carbonate and silicon (believed to play biological roles). Traditional methods of hydroxyapatite synthesis are time consuming and require strict reaction parameter control. This paper outlines synthesis of magnesium substituted hydroxyapatite using simple microwave irradiation of precipitated suspensions. Microwave irradiation resulted in a drastic decrease in ageing times of amorphous apatitic phases. Time taken to synthesize hydroxyapatite (which remained stable upon heat treatment at 900°C for 1h) reduced twelve folds (to 2h) as compared to traditionally required times. The effects of increasing magnesium concentration in the precursors on particle size, surface area, phase-purity, agglomeration and thermal stability, were observed using scanning electron microscopy, BET surface area analysis, X-ray diffraction and photo acoustic Fourier transform infra-red spectroscopy. Porous agglomerates were obtained after a brief heat-treatment (1h) at 900°C.

  14. 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.

  15. Use of ultrafiltration probes in sheep to collect interstitial fluid for measurement of calcium and magnesium.

    Science.gov (United States)

    Janle, E M; Sojka, J E

    2000-11-01

    Studies of calcium and magnesium changes in living animals usually involve blood, urine, and fecal samples. These samples provide only information on whole-body averages and give no indication of differences between tissues. Ultrafiltration probes were developed to sample interstitial fluid from muscle, bone, and subcutaneous tissue of sheep to provide a tool for investigating tissue differences in calcium and magnesium concentrations. The potential of the probes for mineral distribution studies was demonstrated in sheep by using infusion of a calcium gluconate solution.

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

    Indian Academy of Sciences (India)

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

    2012-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Song Changjiang

    2009-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Junji Takaya

    2011-01-01

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

  19. Effect of thermal processing on microstructure and mechanical properties of AZ80 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The influences of deformation temperature and deformation degree on the mierostructure and mechanical properties of AZ80 magnesium alloy were investigated by the adoption of isothermal plain strain compression experiment. The results show that thermal compression processing can refine the grain size and the tensile strength of all the deformed AZ80 magnesium alloys is increased to the maximum of 320 MPa. With the increasing of deformation temperature, the tensile strength decreases; with the increasing of the deformation degree, the tensile strength increases significantly in the temperature range of 200-300 ℃ and becomes stable at temperature higher than 300 ℃. During the compression processing of AZ80 magnesium alloys, at lower temperature(300 ℃), dynamic reerystallization is complete and refined grainstrengthening is dominant, leading to little effect of deformation degree on mechanical properties.

  20. Effects of High Magnetic Field on Solidification and Corrosion Behaviors of Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The solidification behaviors of AZ61 magnesium alloy under a high magnetic field were studied. The corrosion property of AZ61 alloy was investigated in a solution of 3.5 mol/L NaCl by measuring electrochemical polarization. The results show that the high magnetic field can refine microstructure and benefit aluminum transfer.The crystal of α-Mg is induced to orient with their c-axis parallel to the magnetic field. The corrosion studies indicate that different crystal plane of magnesium has different corrosion property. The passivating films on the a- and b-planes have higher corrosion resistance than that on the c-plane. Aligned structure affects the corrosion property of AZ61 magnesium alloy.

  1. Magnesium Contamination in Soil at a Magnesite Mining Region of Liaoning Province, China.

    Science.gov (United States)

    Wang, Lei; Tai, Peidong; Jia, Chunyun; Li, Xiaojun; Li, Peijun; Xiong, Xianzhe

    2015-07-01

    Magnesite is the world's most important source material for magnesia refractory production, and Haicheng City in Liaoning Province, China has been called "the magnesium capital of the world." However, magnesite mining in these areas has caused serious environmental problems. Field investigations have shown that the soil profile of many sites in the mining region are contaminated by magnesium, and the magnesium-enriched crusts that have formed on the soil surface have affected ecologically important soil functions, particularly reduced water penetration rate. Laboratory experiment revealed that anionic polyacrylamide and calcium dihydrogen phosphate can be used to improve soil condition, and have positive effects on soil function. The findings of this study are of significance in the magnetite mining areas, providing clear options for the remediation of soils that should be carried out immediately.

  2. Effect of cadmium or magnesium on calcium-dependent central function that reduces blood pressure

    Energy Technology Data Exchange (ETDEWEB)

    Sutoo, D.; Akiyama, K. [Univ. of Tsukuba (Japan). Inst. of Medical Sci.

    2000-03-01

    The effect of intracerebroventricular (i.c.v.) administration of cadmium or magnesium on central calcium-dependent blood pressure regulation was investigated. The systolic blood pressure of spontaneously hypertensive rats (SHR; male, 13 weeks of age) decreased following i.c.v. administration of cadmium chloride (20 nmol/rat), and increased following i.c.v. administration of magnesium chloride (20, 600, and 1200 nmol/rat). The hypotensive effect of cadmium was suppressed by i.c.v. administration of W-7 (a calmodulin antagonist, 30 {mu}g/rat). Taking into consideration these results with our previous reports, it is suggested that cadmium binds to the calcium-binding sites of calmodulin and activates calcium/calmodulin-dependent enzymes in a disorderly manner, whereas magnesium does not. Therefore, cadmium increases dopamine synthesis in the brain via a calmodulin-dependent system, and the resultant increase in dopamine levels inhibits sympathetic nerve activity and reduces blood pressure in SHR. (orig.)

  3. 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.

  4. ENVIRONMENTAL FRIENDLY ANODIZING ON AZ91D MAGNESIUM ALLOYS AND COATING CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    A. Saijo; M. Hino; M. Hiramatsu; T. Kanadani

    2005-01-01

    An environmental friendly anodizing treatment (Anomag) from a phosphate-based solution without heavy metals on AZ91D magnesium alloy was studied. The characteristics of the coatings,such as structure, composition and corrosion resistance were investigated. The effects of this anodizing treatment on the mechanical properties were examined. X-ray diffraction (XRD) analysis revealed that the structure of the coatings is amorphous or glassy. In salt spray tests coatings with an average thickness of 10μm had an anticorrosive performance of over 1000 hours. Fatigue tests revealed that anodizing onto AZ91D magnesium alloy does not affect the fatigue strength. These results demonstrate the utility of this anodizing treatment on magnesium alloy for application as a structural material, such as in the automotive field.

  5. Electroplating zinc transition layer for electroless nickel plating on AM60 magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-min; ZHOU Wan-qiu; HAN En-Hou

    2006-01-01

    Electroplating zinc coating as transition layer of electroless nickel plating on AM60 magnesium alloys was investigated. The zinc film can be deposited in a pyrophosphate bath at 50-60 ℃ under current density of 0.5-1.5 A/dm2. A new fore treatment technology was applied by acid cleaning with a solution containing molybdate and phosphorous acid, by alkaline cleaning in a bath containing molybdate and sodium hydroxide. The subsequent electroless plating was carried out in nickel sulfate bath. The SEM observation shows that the deposition is uniform and compact. The polarization curve measurements show that the corrosion potential of the zinc plating in 3.5% NaCl is about -1.3 V(vs SCE) which is noble than that of magnesium substrate. The zinc electroplating can be applied as the pretreatment process for electroless nickel plating on magnesium alloys.

  6. Phase equilibria of the magnesium sulfate-water system to 4 kbars

    Science.gov (United States)

    Hogenboom, D. L.; Kargel, J. S.; Ganasan, J. P.; Lee, L.

    1993-01-01

    Magnesium sulfate is the most abundant salt in carbonaceous chondrites, and it may be important in the low-temperature igneous evolution and aqueous differentiation of icy satellites and large chondritic asteroids. Accordingly, we are investigating high-pressure phase equilibria in MgSO4-H2O solutions under pressures up to four kbars. An initial report was presented two years ago. This abstract summarizes our results to date including studies of solutions containing 15.3 percent, 17 percent, and 22 percent MgSO4. Briefly, these results demonstrate that increasing pressure causes the eutectic and peritectic compositions to shift to much lower concentrations of magnesium sulfate, and the existence of a new low-density phase of magnesium sulfate hydrate.

  7. Effect of magnesium addition on the wetting of alumina by aluminium

    Science.gov (United States)

    Sangghaleh, Ali; Halali, Mohammad

    2009-07-01

    In this report the wetting behaviour between polycrystalline alumina substrates and molten aluminium doped with magnesium as a wetting agent has been studied using the sessile drop technique. The time required for equilibrium attainment is investigated. To explore the formation of possible phases at the interface, electron microscopic studies along with EDX analysis have been employed. It is found that magnesium reduces the time and temperature required for equilibrium in the Al/Al 2O 3 system. The Al-7 wt% Mg and Al-10 wt% Mg alloys can wet alumina at temperatures as low as 900 °C. It is also found that molten aluminium doped with magnesium can wet polycrystalline alumina at temperatures below 1000 °C. A thin reaction layer was observed at the Al-Mg/Al 2O 3 interface in the present study.

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

    Directory of Open Access Journals (Sweden)

    Daniel Fruchart

    2012-08-01

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

  9. 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.

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  12. 75 FR 9252 - Magnesium From China and Russia

    Science.gov (United States)

    2010-03-01

    ... COMMISSION Magnesium From China and Russia AGENCY: United States International Trade Commission. ] ACTION: Institution of five-year reviews concerning the antidumping duty orders on magnesium from China and Russia... antidumping duty orders on magnesium from China and Russia would be likely to lead to continuation...

  13. New development of anodizing process of magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    BAI Li-qun; LI Di

    2004-01-01

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

  14. China’s Magnesium and Titanium Industry Development

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>Motivated by the market demand out of the increasing usage of magnesium in the various fields, China’s magnesium production in 2005 reached 467,600 tons, which is an increase of 139.8 per cent on the basis of the year 2000, and China has become the world largest magnesium producing country for the eighth successive year.

  15. 40 CFR 721.10021 - Magnesium potassium titanium oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Magnesium potassium titanium oxide... Specific Chemical Substances § 721.10021 Magnesium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as magnesium...

  16. 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...

  17. Diffuse large B-cell lymphoma associated with the use of biologic and other investigational agents: the importance of long-term post-marketing safety surveillance.

    Science.gov (United States)

    Goddard, Allison; Borovicka, Judy H; West, Dennis P; Evens, Andrew M; Laumann, Anne

    2011-01-01

    This case report describes a patient who developed diffuse large B-cell lymphoma (DLBCL) after receiving courses of two investigational biologic agents and cyclosporine followed by more than four years of subcutaneous efalizumab for the treatment of extensive chronic plaque psoriasis. Three years later, the patient remains free of lymphoma and his psoriasis is well controlled with thrice-weekly narrow-band ultraviolet phototherapy. This case emphasizes the importance of continued long-term post-marketing safety surveillance and the early reporting of all possible serious side effects, including cancers, related to the use of any newly available product. In particular, surveillance should focus on the immunomodulating biologic agents in order to identify possible dangerous sequelae.

  18. Spectroscopic investigation on kinetics, thermodynamics and mechanism for electron transfer reaction of iron(III) complex with sulphur centered radical in stimulated biological system.

    Science.gov (United States)

    Deepalakshmi, S; Sivalingam, A; Kannadasan, T; Subramaniam, P; Sivakumar, P; Brahadeesh, S T

    2014-04-24

    Electron transfer reactions of biological organic sulphides with several metal ions to generate sulphide radical cations are a great concern in biochemical process. To understand the mechanism, a stimulated biological system having model compounds, iron(III)-bipyridyl complex with thio-diglycolic acid (TDGA) was investigated. Spectroscopic study reveals the kinetics and thermodynamics of the reaction in aqueous perchloric acid medium. The reaction follows first and fractional order of 0.412 with respect to [Fe(bpy)3](3+) and TDGA, respectively. The oxidation is insensitive to variation in [H(+)] but slightly decreases with increase in ionic strength ([I]). Addition of acrylamide, a radical scavenger has no effect on the rate of the reaction. The high negative value of ΔS(#) (-74.3±1.09 J K(-1) mol(-1)) indicates the complex formed has a definite orientation higher than the reactants. Based on the above results, a suitable reaction mechanism for this reaction is proposed.

  19. Investigation of the chemical composition of ash generated from Kosovo lignite and the possibility for biological land reclamation on ash dumps

    Energy Technology Data Exchange (ETDEWEB)

    Urosevic, D.; Filipovic, R. [Mining Institute Belgrade, Belgrade (Yugoslavia)

    1997-07-01

    This paper presents the results of investigation of the chemical composition and other properties of ash generated in the coal combustion process in the coal-fired power plants Kosovo, in order to determine the possibilities for biological land reclamation on ash dumps and other degraded soil surfaces. It was established that a certain chemical composition of ash has a beneficial effect on biological land reclamation of ash dumps, thus protecting the environment (i.e. the area surrounding the ash dumps), against pollution. It was concluded that, because of the high percentage of calcium and other earth-alkaline and toxic elements, the ash should not be used as substitution for agricultural production. Ash dumps in Kosovo are not so susceptible to erosion since CaO{sub 3} acts as a binding component. 22 refs., 7 tabs.

  20. Role of magnesium in cardiovascular diseases.

    Science.gov (United States)

    Kolte, Dhaval; Vijayaraghavan, Krishnaswami; Khera, Sahil; Sica, Domenic A; Frishman, William H

    2014-01-01

    Magnesium, the fourth most abundant cation in the human body, is involved in several essential physiological, biochemical, and cellular processes regulating cardiovascular function. It plays a critical role in modulating vascular smooth muscle tone, endothelial cell function, and myocardial excitability and is thus central to the pathogenesis of several cardiovascular disorders such as hypertension, atherosclerosis, coronary artery disease, congestive heart failure, and cardiac arrhythmias. This review discusses the vasodilatory, anti-inflammatory, anti-ischemic, and antiarrhythmic properties of magnesium and its current role in the prevention and treatment of cardiovascular disorders.