Modelling of electrolyte mixtures with application to chemical equilibria in mixtures—prototypes of blood's plasma and calcification of soft tissues

Глинкина, И. В.; Durov, V. A.; Mel'nitchenko, Galina A.

doi:10.1016/j.molliq.2003.09.001

Cited by 8 publications

(4 citation statements)

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“…Many biological fluids, including blood, milk, extracellular fluid, saliva, urine, synovial fluid and cerebrospinal fluid, are usually supersaturated with respect to hydroxyapatite (HA) [1–5], but generally remain stable. Nevertheless, dystrophic calcification does occur, and vascular calcification or stone‐forming biofluids, for example, have serious consequences for human health.…”

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confidence: 99%

Role of calcium phosphate nanoclusters in the control of calcification

2009

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Many biological fluids, including blood, milk, extracellular fluid, saliva, urine, synovial fluid and cerebrospinal fluid, are usually supersaturated with respect to hydroxyapatite (HA) [1][2][3][4][5], but generally remain stable. Nevertheless, dystrophic calcification does occur, and vascular calcification or stone-forming biofluids, for example, have serious consequences for human health. Genetic ablation and other experiments on individual serum proteins have demonstrated the importance of serum fetuin A (FETUA), osteopontin (OPN) and matrix Gla protein (MGP) for inhibiting the precipitation of calcium phosphate (CaP) in serum and preventing ectopic calcification of soft tissues [6][7][8]. A metastable, colloidal, complex of CaP with FETUA, MGP and secretory phosphoprotein 24 (SPP-24) forms when the serum is destabilized [9,10], but the physiological mechanism is still unclear.Milk provides an example of a biofluid that seldom forms CaP precipitates or causes dystrophic calcification of the mammary gland, even though it may contain very much higher concentrations of calcium (Ca) and inorganic phosphorus (P i ) than does serum [11]. In milk, casein micelles sequester CaP through phosphate centre (PC) sequences, typically pSpSpSEE, in Calcium phosphate nanoclusters are equilibrium particles of defined chemical composition in which a core of amorphous calcium phosphate is sequestered within a shell of casein phosphopeptides. Sequence analyses and a structure prediction method were applied to secreted phosphoproteins of known importance in controlling calcification, and eight noncasein phosphoproteins were identified as containing one or more subsequences capable of forming nanoclusters. Small-angle X-ray scattering was used to confirm that a plasmin phosphopeptide of one of the identified proteins, osteopontin, formed a novel type of calcium phosphate nanocluster in which the radius of the amorphous calcium phosphate core was four times larger than is typical of casein nanoclusters. A thermodynamic treatment of nanocluster formation identified the factors of importance in determining the equilibrium size of the core, and showed how a nanocluster solution could be thermodynamically stable yet supersaturated with respect to the mineral phase of bones and teeth. It is suggested that the ability of some secreted phosphoproteins to form nanoclusters is physiologically important for the control or inhibition of calcification in soft and mineralized tissues, the extracellular matrix and a wide range of biofluids, including milk and blood.Abbreviations ACP, amorphous calcium phosphate; CaP, calcium phosphate; CPN, calcium phosphate nanocluster; DCPD, di-calcium phosphate di-hydrate; DMP1, dentin matrix acidic phosphoprotein 1; FETUA, fetuin A; HA, hydroxyapatite; MGP, matrix Gla protein; OCP, octacalcium phosphate; OPN, osteopontin; PC, phosphate centre; pS, phosphoseryl residue; RBP, riboflavin-binding protein; SAXS, small-angle X-ray scattering; SCPP, secretory calcium-binding phosphoprotein; SP, secreted phosphoprot...

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Role of calcium phosphate nanoclusters in the control of calcification

2009

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“…In (2), ε is the dielectric constant of water at 298.15 K and T is the absolute temperature (Kelvin). We also considered, in (1), the product Ba ∼ = 1.5, as suggested by Glinkina et al [9] and recommended by IUPAC (Bates-Guggenhein convention for chloride ion). This approximation is valid when the ionic force is lesser than 0.2 mol/L.…”

Section: Methodsmentioning

confidence: 99%

“…One can note that inert ions, as chloride, do not take part in equilibrium reactions, but their higher concentrations affect the solution ionic force (see 3). The equilibrium constants for the above reactions are found elsewhere [9].…”

Section: Methodsmentioning

confidence: 99%

Theoretical and Experimental Aspects of the Corrosivity of Simulated Soil Solutions

Sena

Bastos

Platt

2012

ISRN Chemical Engineering

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Corrosion of buried steel pipe is a permanent engineering problem and, albeit the counter measures against degradation, when the corrosion process takes place, the damage has costly impact. In order to study the corrosion behavior of pipelines, it is possible to use actual soil extracts or simulated soil solutions. The extract is much related to specific sites and consequently too strict to permit a general understanding. The simulated soil presents, as advantage, its inorganic characteristic and easy preparation. In this paper, we present some theoretical results concerning the chemical equilibria of NS1, NS2, NS3, and NS4 simulated soil solutions. Besides, we have studied the effect of the above four media in corrosion behavior and polarization curves were performed for an API 5L X65 steel. The theoretical findings show that each ionic concentration varies for a 6–12 pH range. The experimental data suggested that the corrosion currents decrease as high is the pH and increase as high is the chloride content. Notwithstanding these facts, for multielectrolyte solutions, a simple correlation with a given ion is not straightforward but the complementary approaches used here give useful insights.

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“…is the dielectric constant of water at 298.15 K and T is the absolute temperature (Kelvin). Also in (1), we considered the product as suggested by Glinkina et al [3] (Bates-Guggenhein convention for chloride ions). This assumption is valid for ionic forces below 0.2 mol·L −1 , as is the case for SBF solutions [4].…”

Section: Thermodynamic Modelsmentioning

confidence: 99%

In Silico Experiments of Carbon Dioxide Atmosphere and Buffer Type Effects on the Biomimetic Coating with Simulated Body Fluids

Platt

Bastos²,

Andrade³

et al. 2012

AMPC

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The formation of calcium phosphate phases is extremely important in a biomedical engineering context. These phosphates are used in many applications, such as grafts, drug-delivery processes and evaluation of the bioactivity of metallic surfaces. Considering this scenario, it is useful to evaluate the thermodynamic conditions for the precipitation of phosphates of biomedical interest, mainly hydroxyapatite. In this work, we investigate the effects of two important factors using a thermodynamic framework: 1) carbon dioxide partial pressure; and 2) buffer type (2-Amino-2-hydroxy- methyl-propane-1,3-diol, known as TRIS and 2-[4-(2-hydroxyethyl)piperazin-1-yl] ethanesulfonic acid, also called HEPES), on the driving force behind the precipitation of calcium phosphates in simulated body fluids. The in silico results show that the pH value is governed by carbon dioxide content, as expected to occur in vivo. Moreover, the buffers can deplete the free calcium available in solution and, consequently, can cause difficulties in the calcium phosphate precipitation.

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Modelling of electrolyte mixtures with application to chemical equilibria in mixtures—prototypes of blood's plasma and calcification of soft tissues

Cited by 8 publications

References 4 publications

Role of calcium phosphate nanoclusters in the control of calcification

Role of calcium phosphate nanoclusters in the control of calcification

Theoretical and Experimental Aspects of the Corrosivity of Simulated Soil Solutions

<i>In Silico</i> Experiments of Carbon Dioxide Atmosphere and Buffer Type Effects on the Biomimetic Coating with Simulated Body Fluids

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Modelling of electrolyte mixtures with application to chemical equilibria in mixtures—prototypes of blood's plasma and calcification of soft tissues

Cited by 8 publications

References 4 publications

Role of calcium phosphate nanoclusters in the control of calcification

Role of calcium phosphate nanoclusters in the control of calcification

Theoretical and Experimental Aspects of the Corrosivity of Simulated Soil Solutions

&lt;i&gt;In Silico&lt;/i&gt; Experiments of Carbon Dioxide Atmosphere and Buffer Type Effects on the Biomimetic Coating with Simulated Body Fluids

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<i>In Silico</i> Experiments of Carbon Dioxide Atmosphere and Buffer Type Effects on the Biomimetic Coating with Simulated Body Fluids