Experimental studies of dependence of the saturation concentration of the CAO-SIO2 B2O3-AL2O3 system magnesium oxide on the basiсiy and content of B2O3

Study of the effect of boron oxide and basicity of CaO – SiO2–B2O3 – Al2O3slag system on MgO saturation concentration was carried out using the simplex lattice method of experimental design, which allows one to construct mathematical models describing dependence of studied property on composition as a continuous function. Synthetic slags, corresponding in composition to vertices of studied simplex, were smelted in graphite crucibles from previously calcined oxides of analytical grade. Slag compositions corresponding to the remaining points of local simplex plan were obtained by counterblending slags of simplex tops. Using experimental data, mathematical models adequately describing effect of slag composition on saturation concentration of MgO were constructed. Graphic image of mathematical modeling results is represented by the composition diagram – saturation concentration of MgO. Analysis of experimental data presented in diagram made it possible to obtain new information on the effect of boron oxide and basicity of CaO – SiO2 – B2O3slags system containing Al2O3on MgO saturation concentration. It was established that in slags formed in basicity range of 2 – 3 and B2O3content of 1 – 3 %, saturation concentration of MgO varies from 3 to 9 %. Increase in B2O3content in slag to 4 % leads to an increase in MgO saturation concentration in slag of 11 – 13 %. Displacement of slags to area of increased basicity up to 3 – 4 is characterized by a decrease in MgO saturation concentration to 2 – 5 %, with 1 – 3 % of В2О3content and an increase to 7 – 9 % at 3 – 4 % В2О3in slag. Formation of slags in basicity range of 4 – 5 and B2O3content of 1 – 3 % does not lead to a significant decrease in concentration of slag saturation with magnesium oxide. Saturation concentration of MgO in slag in this area of basicity varies from 2 to 4 % and practically does not reach 7 % with an increase in В2О3content to 4 %. At the same time, there is an increase in cost of steel due to an increase in consumption of lime and material containing boron oxide.

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A Randomized Trial of Magnesium Oxide and Oral Carbon Adsorbent for Coronary Artery Calcification in Predialysis CKD

Journal of the American Society of Nephrology ◽

10.1681/asn.2018111150 ◽

2019 ◽

Vol 30 (6) ◽

pp. 1073-1085 ◽

Cited By ~ 27

Author(s):

Yusuke Sakaguchi ◽

Takayuki Hamano ◽

Yoshitsugu Obi ◽

Chikako Monden ◽

Tatsufumi Oka ◽

...

Keyword(s):

Coronary Artery ◽

Magnesium Oxide ◽

Coronary Artery Calcification ◽

Controlled Trial ◽

Experimental Studies ◽

Carbon Adsorbent ◽

Dropout Rate ◽

Percentage Change ◽

Control Group ◽

Uremic Toxin

BackgroundDeveloping strategies for managing coronary artery calcification (CAC) in patients with CKD is an important clinical challenge. Experimental studies have demonstrated that magnesium inhibits vascular calcification, whereas the uremic toxin indoxyl sulfate aggravates it.MethodsTo assess the efficacy of magnesium oxide (MgO) and/or the oral carbon adsorbent AST-120 for slowing CAC progression in CKD, we conducted a 2-year, open-label, randomized, controlled trial, enrolling patients with stage 3−4 CKD with risk factors for CAC (diabetes mellitus, history of cardiovascular disease, high LDL cholesterol, or smoking). Using a two-by-two factorial design, we randomly assigned patients to an MgO group or a control group, and to an AST-120 group or a control group. The primary outcome was percentage change in CAC score.ResultsWe terminated the study prematurely after an interim analysis with the first 125 enrolled patients (of whom 96 completed the study) showed that the median change in CAC score was significantly smaller for MgO versus control (11.3% versus 39.5%). The proportion of patients with an annualized percentage change in CAC score of ≥15% was also significantly lower for MgO compared with control (23.9% versus 62.0%). However, MgO did not suppress the progression of thoracic aorta calcification. The MgO group’s dropout rate was higher than that of the control group (27% versus 17%), primarily due to diarrhea. The percentage change in CAC score did not differ significantly between the AST-120 and control groups.ConclusionsMgO, but not AST-120, appears to be effective in slowing CAC progression. Larger-scale trials are warranted to confirm these findings.

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Synthesis of Magnesium Oxide Nanopowder by Thermal Plasma Using Magnesium Nitrate Hexahydrate

Physics Research International ◽

10.1155/2016/6853405 ◽

2016 ◽

Vol 2016 ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

V. Sirota ◽

V. Selemenev ◽

M. Kovaleva ◽

I. Pavlenko ◽

K. Mamunin ◽

...

Keyword(s):

Magnesium Oxide ◽

Thermal Plasma ◽

Experimental Studies ◽

Analytical Techniques ◽

Magnesium Nitrate ◽

Nitrate Hexahydrate ◽

X Ray Diffraction ◽

Magnesium Nitrate Hexahydrate ◽

Transmission Electron ◽

Characterization Studies

Magnesium oxide (MgO) nanopowder was synthesized by thermal plasma in a novel thermal DC plasma torch using magnesium nitrate hexahydrate. Magnesium nitrate hexahydrate (Mg(NO3)2·6H2O) was obtained from serpentinite (Mg3Si2O5(OH)4; lizardite) (Halilovskiy array, Orenburg region, Russia). The synthesized samples were characterized by analytical techniques including X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD and TEM characterization studies confirmed that MgO nanopowder obtained has periclase structure with high purity, and the particle sizes vary within the range of 100 nm to 150 nm. We believe that the present work will promote further experimental studies on the physical properties and the applications of MgO nanopowders in the fields such as high-densed ceramics, additives in bactericide, and refractory products.

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Observations of the Thermal Decomposition of Brucite

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101980 ◽

1968 ◽

Vol 26 ◽

pp. 446-447

Author(s):

P. L. Burnett ◽

W. R. Mitchell ◽

C. L. Houck

Keyword(s):

Thermal Decomposition ◽

Magnesium Oxide ◽

Basal Plane ◽

Magnesium Ions ◽

A Value ◽

Reaction Proceeds

Natural Brucite (Mg(OH)2) decomposes on heating to form magnesium oxide (MgO) having its cubic ﹛110﹜ and ﹛111﹜ planes respectively parallel to the prism and basal planes of the hexagonal brucite lattice. Although the crystal-lographic relation between the parent brucite crystal and the resulting mag-nesium oxide crystallites is well known, the exact mechanism by which the reaction proceeds is still a matter of controversy. Goodman described the decomposition as an initial shrinkage in the brucite basal plane allowing magnesium ions to shift their original sites to the required magnesium oxide positions followed by a collapse of the planes along the original <0001> direction of the brucite crystal. He noted that the (110) diffraction spots of brucite immediately shifted to the positions required for the (220) reflections of magnesium oxide. Gordon observed separate diffraction spots for the (110) brucite and (220) magnesium oxide planes. The positions of the (110) and (100) brucite never changed but only diminished in intensity while the (220) planes of magnesium shifted from a value larger than the listed ASTM d spacing to the predicted value as the decomposition progressed.

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3-D reconstruction and analysis of mammalian mitotic spindle structure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123295 ◽

1992 ◽

Vol 50 (1) ◽

pp. 578-579

Author(s):

Kent McDonald ◽

David Mastronarde ◽

Rubai Ding ◽

Eileen O'Toole ◽

J. Richard McIntosh

Keyword(s):

Cross Sections ◽

Mitotic Spindle ◽

Experimental Studies ◽

Video Camera ◽

Three Dimensions ◽

Mitotic Spindles ◽

Black And White ◽

Reconstruction Methods ◽

Spindle Structure ◽

Tissue Culture Line

Mammalian spindles are generally large and may contain over a thousand microtubules (MTs). For this reason they are difficult to reconstruct in three dimensions and many researchers have chosen to study the smaller and simpler spindles of lower eukaryotes. Nevertheless, the mammalian spindle is used for many experimental studies and it would be useful to know its detailed structure.We have been using serial cross sections and computer reconstruction methods to analyze MT distributions in mitotic spindles of PtK cells, a mammalian tissue culture line. Images from EM negatives are digtized on a light box by a Dage MTI video camera containing a black and white Saticon tube. The signal is digitized by a Parallax 1280 graphics device in a MicroVax III computer. Microtubules are digitized at a magnification such that each is 10-12 pixels in diameter.

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Time-resolved high-resolution electron microscopy of structural stability in mgo clusters

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100165823 ◽

1996 ◽

Vol 54 ◽

pp. 672-673

Author(s):

T. Kizuka ◽

N. Tanaka

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Magnesium Oxide ◽

Structural Stability ◽

High Resolution Electron Microscopy ◽

Video Tape ◽

Solid State Physics ◽

Time Resolved ◽

Resolution Electron ◽

Structural And Functional Properties

Structure and stability of atomic clusters have been studied by time-resolved high-resolution electron microscopy (TRHREM). Typical examples are observations of structural fluctuation in gold (Au) clusters supported on silicon oxide films, graphtized carbon films and magnesium oxide (MgO) films. All the observations have been performed on the clusters consisted of single metal element. Structural stability of ceramics clusters, such as metal-oxide, metal-nitride and metal-carbide clusters, has not been observed by TRHREM although the clusters show anomalous structural and functional properties concerning to solid state physics and materials science.In the present study, the behavior of ceramic, magnesium oxide (MgO) clusters is for the first time observed by TRHREM at 1/60 s time resolution and at atomic resolution down to 0.2 nm.MgO and gold were subsequently deposited on sodium chloride (001) substrates. The specimens, single crystalline MgO films on which Au particles were dispersed were separated in distilled water and observed by using a 200-kV high-resolution electron microscope (JEOL, JEM2010) equipped with a high sensitive TV camera and a video tape recorder system.

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