scholarly journals Role of Hydrodynamics, Li+ Addition and Transformation Kinetics on the Formation of Plate-Like {001} Calcite Crystals

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 250
Author(s):  
Nives Matijaković Matijaković Mlinarić ◽  
Jasminka Kontrec ◽  
Branka Njegić Njegić Džakula ◽  
Giuseppe Falini ◽  
Damir Kralj
Keyword(s):  
Crystal Growth ◽  
Ultrasound Irradiation ◽  
Research Model ◽  
Transformation Kinetics ◽  
Lithium Ions ◽  
Mechanical Stirring ◽  
Wide Range ◽  
Experimental Parameters ◽  
Kinetics Of

Plate-like calcite crystals with expressed unstable {001} planes are interesting research model for investigations of interfacial interactions of different additive molecules, but also the crystal growth mechanisms. The aim of this study is to reproducibly prepare a significant amount of well-defined plate-like calcite crystals and to investigate the critical experimental parameters. Thus, in precipitation system c(NaHCO3) = c(CaCl2) = 0.1 mol dm−3, the influence of hydrodynamic parameters (mode of mixing of the reaction components) and a presence of lithium ions Li+ within a wide range of concentrations, 0.0 mol dm−3 < c(Li+) < 1.0 mol dm−3, have been studied. In addition, the kinetics of the solution mediated transformation of the initially formed metastable polymorph, vaterite, were followed in order to reproducibly describe the formation of stable calcite with expressed unstable morphology. The results indicate that the plate-like calcite is formed predominantly when the ultrasound irradiation is applied at c(Li+) ≥ 0.3 mol dm−3. On the other hand, when the magnetic and mechanical stirring are applied at higher Li+ concentrations, truncated rhombohedral crystals in a mixture with plate-like crystals are obtained. It was also found that the Li+ addition significantly prolonged the transformation, mainly by inhibiting the crystal growth of calcite.

scholarly journals Unexpected Role of Electronic Coupling between Host Redox Centers in Transport Kinetics of Lithium Ions in Olivine Phosphate Materials

2021 ◽  
Author(s):  
Yu Gao ◽  
Jun Huang ◽  
Yuwen Liu ◽  
Shengli Chen
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Lithium Ion ◽  
Transport Kinetics ◽  
Electronic Coupling ◽  
Lithium Ions ◽  
Kinetics Of ◽  
Olivine Phosphate ◽  
Redox Centers

The discrepancy between the trend in the diffusion coefficient of lithium ion (DLi+) and that in the activation energy of ion hopping signals hidden factors determining ion transport kinetics in...

Detailed kinetics of hydrogen abstraction from trans-decalin by OH radicals: the role of hindered internal rotation treatment

2020 ◽  
Vol 22 (44) ◽  
pp. 25740-25746
Author(s):  
Tam V.-T. Mai ◽  
Lam K. Huynh
Keyword(s):  
Master Equation ◽  
Hydrogen Abstraction ◽  
Kinetic Mechanism ◽  
Oh Radicals ◽  
Rate Model ◽  
Wide Range ◽  
Detailed Kinetics ◽  
Kinetics Of ◽  
Detailed Kinetic Mechanism

The detailed kinetic mechanism of the trans-decalin + OH reaction is firstly investigated for a wide range of conditions (T = 200–2000 K & P = 0.76–76000 Torr) using the M06-2X/aug-cc-pVTZ level and stochastic RRKM-based Master equation rate model.

scholarly journals Transformation kinetics of vapor-deposited thin film organic glasses: the role of stability and molecular packing anisotropy

2015 ◽  
Vol 17 (46) ◽  
pp. 31195-31201 ◽  
Author(s):  
Cristian Rodríguez-Tinoco ◽  
Marta Gonzalez-Silveira ◽  
Joan Ràfols-Ribé ◽  
Aitor F. Lopeandía ◽  
Javier Rodríguez-Viejo
Keyword(s):  
Thin Film ◽  
Thermodynamic Stability ◽  
Growth Front ◽  
Molecular Packing ◽  
Front Velocity ◽  
Transformation Kinetics ◽  
Organic Glasses ◽  
Kinetics Of ◽  
Deposition Conditions

The growth front velocity of indomethacin glasses depends on deposition conditions but is not unambigously determined by its thermodynamic stability when the structure is not completely isotropic.

Crystallization Kinetics of Organic–Inorganic Trihalide Perovskites and the Role of the Lead Anion in Crystal Growth

2015 ◽  
Vol 137 (6) ◽  
pp. 2350-2358 ◽  
Author(s):  
David T. Moore ◽  
Hiroaki Sai ◽  
Kwan W. Tan ◽  
Detlef-M. Smilgies ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Crystallization Kinetics ◽  
Kinetics Of

scholarly journals Temporal kinetics of RNAemia and associated systemic cytokines in hospitalized COVID-19 patients

2020 ◽  
Author(s):  
Debby van Riel ◽  
Carmen W.E. Embregts ◽  
Gregorius J. Sips ◽  
Johannes P.C. van den Akker ◽  
Henrik Endeman ◽  
...  
Keyword(s):  
Viral Load ◽  
Inflammatory Cytokines ◽  
Severe Disease ◽  
Respiratory Complications ◽  
Viral Spread ◽  
Cytokines And Chemokines ◽  
Wide Range ◽  
Direct Association ◽  
Kinetics Of

SummaryCOVID-19 is associated to a wide range of extra-respiratory complications, of which the pathogenesis is currently not fully understood. In this study we report the temporal kinetics of viral RNA and inflammatory cytokines and chemokines in serum during the course of COVID-19. We show that a RNAemia occurs more frequently and lasts longer in patients that develop critical disease compared to patients that develop moderate or severe disease. Furthermore we show that concentrations of IL-10 and MCP-1—but not IL-6—are associated with viral load in serum. However, higher levels of IL-6 were associated with the development of critical disease. The direct association of inflammatory cytokines with viral load or disease severity highlights the complexity of systemic inflammatory response and the role of systemic viral spread.

scholarly journals Role of molecular charge and hydrophilicity in regulating the kinetics of crystal growth

2006 ◽  
Vol 103 (51) ◽  
pp. 19237-19242 ◽  
Author(s):  
S. Elhadj ◽  
J. J. De Yoreo ◽  
J. R. Hoyer ◽  
P. M. Dove
Keyword(s):  
Crystal Growth ◽  
Molecular Charge ◽  
Kinetics Of ◽  
Kinetics Of Crystal Growth

scholarly journals Maslinic Acid Nanoparticles: A Drug to Carry Others

2020 ◽  
Vol 4 (1) ◽  
pp. 6
Author(s):  
Pablo Graván ◽  
Aixa Aguilera-Garrido ◽  
Marta Medina-O’Donell ◽  
Andrés Parra ◽  
María J. Gálvez-Ruiz ◽  
...  
Keyword(s):  
Organic Phase ◽  
Volume Ratio ◽  
Maslinic Acid ◽  
Phase Volume Ratio ◽  
Starting Point ◽  
Wide Range ◽  
Experimental Parameters ◽  
Therapeutic Activities ◽  
Harmful Effects

Maslinic acid (MA), a triterpene widely found in natural sources, is a compound which is gaining interest due to its multiple therapeutic activities and its lack of harmful effects. However, MA is practically insoluble in water, which limits its clinical application. Here, we present a solvent displacement method to produce MA Solid Lipid Nanoparticles (SLNs) as a nanoplatform to carry hydrophobic drugs. A systematic study of the experimental parameters that may have some influence on the colloidal characteristics of MA SLNs was carried out. The effect of the aqueous/organic phase volume ratio and the organic phase composition on the size of SLNs evidence the role of the solvent diffusivity on the colloidal characteristic of the SLNs. On the other hand, the effect of surfactant/MA ratio proved the relevance of the surfactant on stabilizing the SLNs interface, owing to the changes on the interfacial tension that it promotes. MA SLNs have proved to be highly stable over time and in a wide range of pH and salinity conditions, as well as having a high curcumin encapsulation efficiency. The MA SLNs prepared in this work provide a starting point to develop functionalized active nanocarriers which allow establishing a synergistic relation with the loaded drug.

scholarly journals Structural-phase transformation kinetics during sintering of alumina ceramics using metastable nanopowders

2005 ◽  
Vol 37 (1) ◽  
pp. 35-43 ◽  
Author(s):  
A.S. Kaigorodov ◽  
V.R. Khrustov ◽  
V.V. Ivanov ◽  
A.I. Medvedev ◽  
A.K. Shtol’ts
Keyword(s):  
Diffusion Processes ◽  
Structural Phase ◽  
Alumina Ceramics ◽  
Transformation Kinetics ◽  
Structural Phase Transformation ◽  
Positive Role ◽  
Polymorphous Transition ◽  
Mg Addition ◽  
Kinetics Of

The processes taking place during pressureless sintering of nano- metastable Al2O3, compacted up to high densities (0.7 of the theoretical density) using the magnetic pulsed method were studied. The influence of MgO, TiO2 and ZrO2 additives on the kinetics of Al2O3 polymorphous transition, shrinkage and microstructure evolution during annealing at temperatures up to 1450?C has been studied. We have found that the process of annealing is two-staged starting with a polymorphous transition. Doping changes the starting temperature as well as the shrinkage depth at both stages. TiO2 and ZrO2 additives decrease the temperature of the onset of shrinkage, whereas MgO increases it. The best composition contained MgO in the series of examined types of ceramics with an ?-Al2O3 matrix. The positive role of Mg addition in the production of dense and hard Al2O3 ceramics is related to the nature of Mg influence on the activation of diffusion processes in Al2O3, as well as to the way of uniform distribution of MgO dopant in the material. All these factors provide effective damping of diffusion processes and limit ?-Al2O3 crystal growth. Highly dense MgO, ZrO2 and TiO2 doped Al2O3 ceramics with a grain size of 190, 220, and 250 nm and microhardness of 22, 17 and 17 GPa, correspondingly have been obtained.

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