scholarly journals Functionalized Multiwalled CNTs in Classical and Nonclassical CaCO3 Crystallization

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1169 ◽  
Author(s):  
Andrónico Neira-Carrillo ◽  
Patricio Vásquez-Quitral ◽  
Marianela Sánchez ◽  
Masoud Farhadi-Khouzani ◽  
Héctor Aguilar-Bolados ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Good Alternative ◽  
Gas Diffusion ◽  
High Tech ◽  
Amorphous Calcium Carbonate ◽  
Multiwalled Carbon ◽  
Selective Crystallization ◽  
First Time ◽  
Functionalized Mwcnts ◽  
Multiwalled Cnts

Multiwalled carbon nanotubes (MWCNTs) are interesting high-tech nanomaterials. MWCNTs oxidized and functionalized with itaconic acid and monomethylitaconate were demonstrated to be efficient additives for controlling nucleation of calcium carbonate (CaCO3) via gas diffusion (GD) in classical as well as nonclassical crystallization, yielding aragonite and truncated calcite. For the first time, all amorphous calcium carbonate (ACC) proto-structures, such as proto calcite-ACC, proto vaterite-ACC and proto aragonite-ACC, were synthesized via prenucleation cluster (PNC) intermediates and stabilized at room temperature. The MWCNTs also showed concentration-dependent nucleation promotion and inhibition similar to biomolecules in nature. Incorporation of fluorescein-5-thiosemicarbazide (5-FTSC) dye-labeled MWCNTs into the CaCO3 lattice resulted in fluorescent hybrid nanosized CaCO3. We demonstrate that functionalized MWCNTs offer a good alternative for controlled selective crystallization and for understanding an inorganic mineralization process.

scholarly journals Avian eggshell formation reveals a new paradigm for vertebrate mineralization via vesicular amorphous calcium carbonate

2020 ◽  
Vol 295 (47) ◽  
pp. 15853-15869 ◽  
Author(s):  
Lilian Stapane ◽  
Nathalie Le Roy ◽  
Jacky Ezagal ◽  
Alejandro B. Rodriguez-Navarro ◽  
Valérie Labas ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Marine Invertebrate ◽  
Vesicular Transport ◽  
Matrix Proteins ◽  
New Paradigm ◽  
Amorphous Calcium Carbonate ◽  
Bicarbonate Ions ◽  
Uterine Fluid ◽  
Vertebrate Model ◽  
First Time

Amorphous calcium carbonate (ACC) is an unstable mineral phase, which is progressively transformed into aragonite or calcite in biomineralization of marine invertebrate shells or avian eggshells, respectively. We have previously proposed a model of vesicular transport to provide stabilized ACC in chicken uterine fluid where eggshell mineralization takes place. Herein, we report further experimental support for this model. We confirmed the presence of extracellular vesicles (EVs) using transmission EM and showed high levels of mRNA of vesicular markers in the oviduct segments where eggshell mineralization occurs. We also demonstrate that EVs contain ACC in uterine fluid using spectroscopic analysis. Moreover, proteomics and immunofluorescence confirmed the presence of major vesicular, mineralization-specific and eggshell matrix proteins in the uterus and in purified EVs. We propose a comprehensive role for EVs in eggshell mineralization, in which annexins transfer calcium into vesicles and carbonic anhydrase 4 catalyzes the formation of bicarbonate ions (HCO3−), for accumulation of ACC in vesicles. We hypothesize that ACC is stabilized by ovalbumin and/or lysozyme or additional vesicle proteins identified in this study. Finally, EDIL3 and MFGE8 are proposed to serve as guidance molecules to target EVs to the mineralization site. We therefore report for the first-time experimental evidence for the components of vesicular transport to supply ACC in a vertebrate model of biomineralization.

scholarly journals A new model for vertebrate mineralization via stabilized amorphous calcium carbonate for avian eggshell formation

2020 ◽  
Author(s):  
Lilian Stapane ◽  
Nathalie Le Roy ◽  
Jacky Ezagal ◽  
Alejandro B. Rodriguez-Navarro ◽  
Valérie Labas ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Experimental Evidence ◽  
Marine Invertebrate ◽  
Vesicular Transport ◽  
Linear Acceleration ◽  
Matrix Proteins ◽  
Amorphous Calcium Carbonate ◽  
Transmission Electron ◽  
Uterine Fluid ◽  
First Time

ABSTRACTAmorphous calcium carbonate (ACC) is an unstable mineral phase, which is progressively transformed into aragonite or calcite in biomineralization of marine invertebrate shells or avian eggshells, respectively. We have previously proposed a model of vesicular transport to provide stabilized ACC in chicken uterine fluid where mineralization takes place. Herein, we report further experimental evidence for this model. We confirmed the presence of extracellular vesicles (EVs) that contain ACC in uterine fluid using transmission electron microscopy and elemental analysis. We also demonstrate high levels of expression of vesicular markers in the oviduct segments where eggshell is formed. Moreover, proteomics and immunofluorescence confirmed the presence of major vesicular, mineralization-specific and eggshell matrix proteins in the uterus and in purified EVs. We propose a comprehensive role for EVs in eggshell mineralization, in which annexins transfer calcium into vesicles and carbonic anhydrase 4 catalyzes the formation of HCO3−, for accumulation of ACC in vesicles. We hypothesize that ACC is stabilized by ovalbumin and/or lysozyme or additional vesicle proteins identified in this study. Finally, EDIL3 and MFGE8 are proposed to serve as guidance molecules to target EVs to the mineralization site. We therefore report for the first time experimental evidence for the components of vesicular transport to supply ACC in vertebrate biomineralization. These results could give insight to understand the mineralization of otoconia, which are calcium carbonate biomineralized structures present in all vertebrates and necessary for balance and sensing linear acceleration.

scholarly journals The Impact of Ambient Atmospheric Mineral-Dust Particles on the Calcification of Lungs

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 125
Author(s):  
Mariola Jabłońska ◽  
Janusz Janeczek ◽  
Beata Smieja-Król
Keyword(s):  
Mineral Dust ◽  
Smoking Habit ◽  
Lower Lobe ◽  
Ambient Air ◽  
Dust Particles ◽  
Masking Effect ◽  
Amorphous Calcium Carbonate ◽  
Calcium Salts ◽  
The Impact ◽  
First Time

For the first time, it is shown that inhaled ambient air-dust particles settled in the human lower respiratory tract induce lung calcification. Chemical and mineral compositions of pulmonary calcium precipitates in the lung right lower-lobe (RLL) tissues of 12 individuals who lived in the Upper Silesia conurbation in Poland and who had died from causes not related to a lung disorder were determined by transmission and scanning electron microscopy. Whereas calcium salts in lungs are usually reported as phosphates, calcium salts precipitated in the studied RLL tissue were almost exclusively carbonates, specifically Mg-calcite and calcite. These constituted 37% of the 1652 mineral particles examined. Mg-calcite predominated in the submicrometer size range, with a MgCO3 content up to 50 mol %. Magnesium plays a significant role in lung mineralization, a fact so far overlooked. The calcium phosphate (hydroxyapatite) content in the studied RLL tissue was negligible. The predominance of carbonates is explained by the increased CO2 fugacity in the RLL. Carbonates enveloped inhaled mineral-dust particles, including uranium-bearing oxides, quartz, aluminosilicates, and metal sulfides. Three possible pathways for the carbonates precipitation on the dust particles are postulated: (1) precipitation of amorphous calcium carbonate (ACC), followed by its transformation to calcite; (2) precipitation of Mg-ACC, followed by its transformation to Mg-calcite; (3) precipitation of Mg-free ACC, causing a localized relative enrichment in Mg ions and subsequent heterogeneous nucleation and crystal growth of Mg-calcite. The actual number of inhaled dust particles may be significantly greater than was observed because of the masking effect of the carbonate coatings. There is no simple correlation between smoking habit and lung calcification.

scholarly journals Pure hydroxyapatite synthesis originating from amorphous calcium carbonate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michika Sawada ◽  
Kandi Sridhar ◽  
Yasuharu Kanda ◽  
Shinya Yamanaka
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Room Temperature ◽  
Molar Ratio ◽  
Final Phase ◽  
Amorphous Calcium Carbonate ◽  
Phosphate Compound ◽  
Synthesis Strategy ◽  
Phosphorylation Reaction ◽  
Subsequent Calcination

AbstractWe report a synthesis strategy for pure hydroxyapatite (HAp) using an amorphous calcium carbonate (ACC) colloid as the starting source. Room-temperature phosphorylation and subsequent calcination produce pure HAp via intermediate amorphous calcium phosphate (ACP). The pre-calcined sample undergoes a competitive transformation from ACC to ACP and crystalline calcium carbonate. The water content, ACC concentration, Ca/P molar ratio, and pH during the phosphorylation reaction play crucial roles in the final phase of the crystalline phosphate compound. Pure HAp is formed after ACP is transformed from ACC at a low concentration (1 wt%) of ACC colloid (1.71 < Ca/P < 1.88), whereas Ca/P = 1.51 leads to pure β-tricalcium phosphate. The ACP phases are precursors for calcium phosphate compounds and may determine the final crystalline phase.

scholarly journals On the Relation of Amorphous Calcium Carbonate and the Macromechanical Properties of Sea Urchin Spines

2020 ◽  
Vol 22 (4) ◽  
pp. 1900922 ◽  
Author(s):  
Christoph Lauer ◽  
Sebastian Haußmann ◽  
Patrick Schmidt ◽  
Carolin Fischer ◽  
Doreen Rapp ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Sea Urchin ◽  
Amorphous Calcium Carbonate ◽  
Sea Urchin Spines

scholarly journals Transformation mechanism of amorphous calcium carbonate into calcite in the sea urchin larval spicule

2008 ◽  
Vol 105 (45) ◽  
pp. 17362-17366 ◽  
Author(s):  
Y. Politi ◽  
R. A. Metzler ◽  
M. Abrecht ◽  
B. Gilbert ◽  
F. H. Wilt ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Sea Urchin ◽  
Amorphous Calcium Carbonate ◽  
Transformation Mechanism

scholarly journals Amorphous calcium carbonate transforms into calcite during sea urchin larval spicule growth

1997 ◽  
Vol 264 (1380) ◽  
pp. 461-465 ◽  
Author(s):  
Elia Beniash ◽  
Joanna Aizenberg ◽  
Lia Addadi ◽  
Stephen Weiner
Keyword(s):  
Calcium Carbonate ◽  
Sea Urchin ◽  
Amorphous Calcium Carbonate

scholarly journals The Synthesis of Peculiar Structure of Springlike Multiwall Carbon Nanofibers/Nanotubes via Mechanothermal Method

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Sahebali Manafi ◽  
Mohammad Reza Rahimipour ◽  
Iman Mobasherpour ◽  
Atefeh Soltanmoradi
Keyword(s):  
Carbon Nanofibers ◽  
Large Scale ◽  
Annealing Temperature ◽  
Milling Time ◽  
Nanocomposite Materials ◽  
Scale Production ◽  
Multiwalled Carbon ◽  
Large Scale Production ◽  
First Time ◽  
Multiwall Carbon

Mechanothermal (MT) method is one of the methods used for large-scale production of carbon nanotubes/nanofibers. The different peculiar morphologies of carbon allotropes are introduced with an extraordinary structure for the first time by MT method. In this paper, the influence of milling time and annealing temperature on the crystallinity and morphology of the synthesized nanopowders was investigated. Surprisingly, in this investigation, we report the synthesis of springlike multiwalled carbon nanofibers (S-MWCNFs) by a two-step annealing of milled graphite in an Ar atmosphere. On the other hand, the MT method could be used for the preparation of suitable structures with applications in nanocomposite materials, which is an important task in the era of nanotechnology.

Biological control over the formation and storage of amorphous calcium carbonate by earthworms

2008 ◽  
Vol 72 (1) ◽  
pp. 227-231 ◽  
Author(s):  
M. J. I. Briones ◽  
E. López ◽  
J. Méndez ◽  
J. B. Rodríguez ◽  
L. Gago-Duport
Keyword(s):  
Electron Microscopy ◽  
Biological Control ◽  
Calcium Carbonate ◽  
Ostwald Ripening ◽  
High Resolution Electron Microscopy ◽  
Amorphous Calcium Carbonate ◽  
Concentrated Suspension ◽  
Selected Area Electron Diffraction ◽  
Resolution Electron ◽  
Glandular Secretion

AbstractThe earthworm calciferous gland produces a concentrated suspension of calcium carbonate and in certain species precipitates as concretions of CaCO3, which then enter the soil. Here we investigated the initial stages of CaCO3 formation in the earthworm Lumbricus friendi by means of Fourier transform infrared and electron microscopy techniques (field-emission scanning electron microscopy, transmission electron microscopy, high resolution electron microscopy and selected area electron diffraction). In addition, comparisons between the IR spectra of the water-dissolved carbonic anhydrase (CA) and the glandular secretion (‘milky fluid’) were performed in order to investigate the mechanisms involved in CaCO3 precipitation. Our results strongly suggest that carbonation starts with the dissolved CO2, which is transformed via deprotonation to HCO3-, then to CO32- and finally to amorphous calcium carbonate (ACC). While ACC stabilization takes place under the biological control, further transformation stages leading to calcite concretions seem to be inorganically driven by an Ostwald ripening process.

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