Inhibitory Effect of MgO, FeO, CaF2, and Al2O3 Additives on the Dissolution Behavior of Ca from Silicate Mineral Phases into Water

The ongoing research on biomaterials that support bone regeneration led to the quest for materials or material modifications that can actively influence the activity or balance of bone tissue cells. The bone biocompatibility of porous chitosan scaffolds was modified in the present study by the addition of calcium phosphates or hemocyanin. The first strategy comprised the incorporation of calcium phosphates into chitosan to create a biomimetic chitosan—mineral phase composite. The second strategy comprised dip-coating of chitosan scaffolds with hemocyanin extracted from crayfish hemolymph. The cytocompatibility was assessed in a mono-culture of human bone marrow stromal cells (hBMSCs) and their differentiation to osteoblasts; in a mono-culture of human monocytes (hMs) and their maturation to osteoclasts; and in a co-culture of hBMSC/osteoblasts—hM/osteoclasts. Mineral incorporation caused an increase in scaffold bioactivity, as shown by reduced calcium concentration in the cell culture medium, delayed differentiation of hBMSCs, and reduced osteoclastic maturation of hMs in mono-culture. Dip-coating with hemocyanin led to increased proliferation of hBMSCs and equivalent osteoclast maturation in mono-culture, while in co-culture, both an inhibitory effect of mineral incorporation on osteoblastogenesis and stimulatory effects of hemocyanin were observed. It was concluded that highly bioactive scaffolds (containing mineral phases) restrain osteoblast and osteoclast development, while hemocyanin coating significantly supports osteoblastogenesis. These influences on the osteoblasts/osteoclasts activity ratio may support scaffold-driven bone healing in the future.

Download Full-text

Melt inclusions in olivines from phoscorites and olivinites of the Kovdor massif.

10.5194/egusphere-egu2020-12611 ◽

2020 ◽

Author(s):

Anna Redina ◽

Cora Wohlgemuth-Ueberwasser ◽

Julia Mikhailova ◽

Gregory Ivanyuk

Keyword(s):

Melt Inclusions ◽

Trace Element Composition ◽

Russian Science ◽

Silicate Mineral ◽

Mineral Phases ◽

Icp Ms ◽

Kola Alkaline Province ◽

Negative Crystal ◽

The Baltic ◽

Silicate Carbonate

The Kovdor massif is a part of the Paleozoic Kola alkaline province and located in the eastern part of the Baltic Shield. Kovdor carbonatites host a unique complex baddeleyite-apatite-magnetite deposit from which iron ores and zirconium have been mined. New data on melt inclusions in olivine crystals from phoscorites and olivinites of the ore complex are presented in this contribution. Daughter minerals in crystallized melt inclusions were identified by Raman spectroscopy and scanning electron microscopy. The trace element composition of inclusions was determined using LA-ICP-MS.Melt inclusions in olivine from Kovdor phoscorites are negative crystal or round in shape, with sizes ranging from 5 to 50 microns. They form groups or line up. According to the mineral composition, two types of melt inclusions can be distinguished: carbonate and silicate-carbonate. In the first type, Ca-Na-Mg- (Sr?) - REE carbonates are dominant among daughter phases. In the second one, silicate phases (phlogopite, monticellite, diopside), Ca-Na-Mg carbonates and magnetite are found together. Melt inclusions in olivine from olivinites are isometric or elongated, 5&#8211;25 &#956;m in size. They form groups or occur as isolated inclusions. Benstoneite, geylussit, ankerite, calcite and hydroxyl-bastnesite along with phyllosilicates (phlogopite, paragonite?) were identified among daughter minerals.The rare earth elements composition of melt inclusions from both types of rocks is characterized by the predominance of light REE. The content of REE, especially light ones, in inclusions from phoscorites is higher. Strontium and barium contents in most melt inclusions have negative correlations with niobium and zirconium concentrations.Melt inclusions from phoscorites and olivinites contain carbonate and silicate mineral phases in various proportions, which may imply heterogeneous trapping of crystalline phases and two immiscible melts, silicate and carbonatite. Inclusions from phoscorite represent a more evolved magma with higher concentrations of rare metals.This work was supported by the Russian Science Foundation, grant No 19-17-00013.

Download Full-text

Synthesis and characterization of 1:1 layered uranyl silicate mineral phases

Chemical Geology ◽

10.1016/j.chemgeo.2010.03.021 ◽

2010 ◽

Vol 274 (3-4) ◽

pp. 149-157 ◽

Cited By ~ 11

Author(s):

Nathalie A. Wall ◽

Sue B. Clark ◽

Jeanne L. McHale

Keyword(s):

Synthesis And Characterization ◽

Silicate Mineral ◽

Mineral Phases

Download Full-text

Modeling The Dissolution Behavior of Defense Waste Glass in A Salt Repository Environment

MRS Proceedings ◽

10.1557/proc-112-595 ◽

1987 ◽

Vol 112 ◽

Author(s):

B. P. McGrail

Keyword(s):

Mechanistic Model ◽

Waste Glass ◽

Dissolution Behavior ◽

Precipitation Reaction ◽

Iron Corrosion ◽

Silicate Mineral ◽

Surface Area Ratio ◽

Dissolved Silica ◽

Glass Dissolution ◽

Radionuclide Release

AbstractA mechanistic model describing a dynamic mass balance between the production and consumption of dissolved silica was found to describe the dissolution behavior of SRL-165 defense waste glass in a high-magnesium brine (PBB3) at a temperature of 90°C. The synergistic effect of the waste package container on the glass dissolution rate was found to depend on a precipitation reaction for a ferrous silicate mineral.The model predicted that the ferrous silicate precipitate should be variable in composition where the iron/silica stoichiometry depended on the metal/glass surface area ratio used in the experiment. This prediction was confirmed experimentally by the variable iron/silica ratios observed in filtered leachates. However, the interaction between dissolved silica and iron corrosion products needs to be much better understood before the model can be used with confidence in predicting radionuclide release rates for a salt repository.

Download Full-text

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109513 ◽

1978 ◽

Vol 36 (1) ◽

pp. 474-475

Author(s):

P.P.K. Smith

Keyword(s):

High Temperature ◽

Low Temperature ◽

Homogeneous Nucleation ◽

Silicate Mineral ◽

Antiphase Boundaries ◽

Two Phase ◽

Primitive Form ◽

The Core ◽

Nucleation Mechanisms ◽

And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Download Full-text

Automated mineral analysis in TASK8

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134661 ◽

1990 ◽

Vol 48 (2) ◽

pp. 212-213

Author(s):

William F. Chambers ◽

Arthur A. Chodos ◽

Roland C. Hagan

Keyword(s):

National Laboratory ◽

Control Program ◽

Mineral Analysis ◽

Alamos National Laboratory ◽

Mineral Phase ◽

Los Alamos National Laboratory ◽

California Institute Of Technology ◽

Mineral Phases ◽

Letter Code ◽

Institute Of Technology

TASK8 was designed as an electron microprobe control program with maximum flexibility and versatility, lending itself to a wide variety of applications. While using TASKS in the microprobe laboratory of the Los Alamos National Laboratory, we decided to incorporate the capability of using subroutines which perform specific end-member calculations for nearly any type of mineral phase that might be analyzed in the laboratory. This procedure minimizes the need for post-processing of the data to perform such calculations as element ratios or end-member or formula proportions. It also allows real time assessment of each data point.The use of unique “mineral codes” to specify the list of elements to be measured and the type of calculation to perform on the results was first used in the microprobe laboratory at the California Institute of Technology to optimize the analysis of mineral phases. This approach was used to create a series of subroutines in TASK8 which are called by a three letter code.

Download Full-text

Conditions for atomic imaging of mullite

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154068 ◽

1989 ◽

Vol 47 ◽

pp. 418-419

Author(s):

T. A. Epicier ◽

G. Thomas

Keyword(s):

Oxygen Vacancies ◽

High Resolution Electron Microscopy ◽

Ceramic Materials ◽

Work Conditions ◽

Real Space ◽

Potential Candidate ◽

Silicate Mineral ◽

Resolution Electron ◽

The Subject ◽

Aluminium Silicate

Mullite is an aluminium-silicate mineral of current interest since it is a potential candidate for high temperature applications in the ceramic materials field.In the present work, conditions under which the structure of mullite can be optimally imaged by means of High Resolution Electron Microscopy (HREM) have been investigated. Special reference is made to the Atomic Resolution Microscope at Berkeley which allows real space information up to ≈ 0.17 nm to be directly transferred; numerous multislice calculations (conducted with the CEMPAS programs) as well as extensive experimental through-focus series taken from a commercial “3:2” mullite at 800 kV clearly show that a resolution of at least 0.19 nm is required if one wants to get a straightforward confirmation of atomic models of mullite, which is known to undergo non-stoichiometry associated with the presence of oxygen vacancies.Indeed the composition of mullite ranges from approximatively 3Al2O3-2SiO2 (referred here as 3:2-mullite) to 2Al2O3-1SiO2, and its structure is still the subject of refinements (see, for example, refs. 4, 5, 6).

Download Full-text