Prediction of analytes' electrophoretic mobility in mixed solvent buffers using Abraham solvation parameters

2015 ◽  
Vol 7 (19) ◽  
pp. 8123-8128
Author(s):  
A. Jouyban ◽  
R. Fazeli-Bakhtiyari ◽  
A. Shayanfar ◽  
W. E. Acree
Keyword(s):  
Electrophoretic Mobility ◽  
Mixed Solvent ◽  
Background Electrolyte ◽  
Solvation Model ◽  
Predictive Equations ◽  
Solvation Parameters ◽  
Abraham Solvation Model

The electrophoretic mobility of analytes in different solvent compositions of the background electrolyte was calculated using a combined version of a previously developed model with the Abraham solvation model for providing predictive equations.

scholarly journals A Comparative Interaction between Copper Ions with Alzheimer'sβAmyloid Peptide and Human Serum Albumin

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
G. Rezaei Behbehani ◽  
L. Barzegar ◽  
M. Mohebbian ◽  
A. A. Saboury
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Copper Ions ◽  
Copper Ion ◽  
Titration Calorimetry ◽  
Solvation Model ◽  
Solvation Parameters ◽  
Induced Aggregation

The interaction of Cu2+with the first 16 residues of the Alzheimer's amyliodβpeptide,Aβ(1–16), and human serum albumin (HSA) were studied in vitro by isothermal titration calorimetry at pH 7.2 and 310 K in aqueous solution. The solvation parameters recovered from the extended solvation model indicate that HSA is involved in the transport of copper ion. Complexes betweenAβ(1–16) and copper ions have been proposed to be an aberrant interaction in the development of Alzheimer's disease, where Cu2+is involved inAβ(1–16) aggregation. The indexes of stability indicate that HSA removed Cu2+fromAβ(1–16), rapidly, decreased Cu-induced aggregation ofAβ(1–16), and reduced the toxicity ofAβ(1–16) + Cu2+significantly.

Quantitative description of analyte migration behavior based on the dynamic complexation model in capillary electrophoresis

1997 ◽  
Vol 75 (5) ◽  
pp. 507-517 ◽  
Author(s):  
Xuejun Peng ◽  
Gwendolyn M. Bebault ◽  
David D.Y. Chen ◽  
Stephen L. Sacks
Keyword(s):  
Capillary Electrophoresis ◽  
Equilibrium Constant ◽  
Electrophoretic Mobility ◽  
Method Development ◽  
Background Electrolyte ◽  
Phase System ◽  
Migration Behavior ◽  
Additive Concentration ◽  
Résolution Équation ◽  
Analyte Migration

A theory based on dynamic complexation is used to describe analyte migration behavior in capillary electrophoresis (CE). This theory is based on a one-phase system, instead of the commonly accepted two-phase system. The migration behavior of an analyte is described by three parameters (the electrophoretic mobility of the free analyte, the electrophoretic mobility of the analyte–additive complex, and the equilibrium constant (formation constant) that determines the fractions of the free analyte and the complex at a certain additive concentration). Varying the additive concentration shifts the equilibrium and changes the viscosity of the background electrolyte. Viscosity correction is crucial in interpreting the observed migration behavior of analytes. While electroosmotic flow in a capillary often varies from one capillary to another, the viscosity of a buffer is characteristic of the buffer composition and is constant for each buffer. The electrophoretic mobility of a certain species and the equilibrium constant are intrinsic properties and are less sensitive to changes in the environment. Understanding these relationships is indispensable in CE method development and method validation. A universal resolution equation is proposed, with a separation factor that has taken both the electrophoretic mobilities and equilibria into consideration. This resolution equation gives clear guidance for the optimization of CE separations. A group of nucleosides and their phosphates are used as analytes, and β-cyclodextrin is used as the additive in the model system studied in this paper. Both the observed analyte migration behavior and the resolution of analytes agree well with this theory. Keywords: dynamic complexation capillary electrophoresis, nucleoside and nucleotide separation, capacity factor, resolution equation, viscosity correction.

Prediction of Electrophoretic Mobility of Analytes Using Abraham Solvation Parameters by Different Chemometric Methods

2017 ◽  
Vol 13 (4) ◽  
Author(s):  
Samin Hamidi ◽  
Ali Shayanfar ◽  
Hossein Hamidi ◽  
Elnaz Mehdizadeh Aghdam ◽  
Abolghasem Jouyban
Keyword(s):  
Electrophoretic Mobility ◽  
Chemometric Methods ◽  
Solvation Parameters

scholarly journals Thermal Study of a Newly Synthesized Cu(II) Complex Binding to Bovineβ-Lactoglobulin

2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
Adeleh Divsalar ◽  
Lyla Barzegar ◽  
Gholamreza Rezaei Behbehani
Keyword(s):  
Thermodynamic Parameters ◽  
Tertiary Structure ◽  
Thermal Study ◽  
Titration Calorimetry ◽  
Solvation Model ◽  
Different Temperatures ◽  
Solvation Parameters ◽  
Partially Unfolded ◽  
Solvation Theory ◽  
Good Agreement

We have investigated the interactions betweenβ-lactoglobulin, BLG, and new synthesized Cu(II) complex (2,2′-dibipyridine Cu(II) chloride) using isothermal titration calorimetry (ITC) methods at different temperatures of 298 and 310 K. The heats of BLG + Cu(II) interactions are reported and analyzed in terms of the extended solvation theory for calculation of binding and thermodynamic parameters of the interaction. The results suggested that binding of Cu(II) complex on BLG resulted in significant changes on the tertiary structure and conformation of protein via increasing of hydrophobicity and inducing partially unfolded structure in BLG which has a good agreement with the solvation parameters recovered by the extended solvation model suggesting destabilization of the protein.

Development of new predictive equations for basal metabolic rate in Iranian healthy adults: negligible effect of sex

2020 ◽  
pp. 1-10
Author(s):  
Bahareh Nikooyeh ◽  
Nastaran Shariatzadeh ◽  
Ali Kalayi ◽  
Maliheh Zahedirad ◽  
Tirang R. Neyestani
Keyword(s):  
Metabolic Rate ◽  
Thyroid Function ◽  
Basal Metabolic Rate ◽  
Age Groups ◽  
Thyroid Function Tests ◽  
Anthropometric Measures ◽  
Predictive Equations ◽  
Normal Thyroid Function ◽  
Asian People ◽  
Predictive Formulas

Abstract. Some studies have reported inaccuracy of predicting basal metabolic rate (BMR) by using common equations for Asian people. Thus, this study was undertaken to develop new predictive equations for the Iranian community and also to compare their accuracy with the commonly used formulas. Anthropometric measures and thyroid function were evaluated for 267 healthy subjects (18–60 y). Indirect calorimetry (InCal) was performed only for those participants with normal thyroid function tests (n = 252). Comparison of predicted RMR (both kcal/d and kcal.kg.wt−1.d−1) using current predictive formulas and measured RMR revealed that Harris-Benedict and FAO/WHO/UNU significantly over-estimated and Mifflin-St. Jeor significantly under-estimated RMR as compared to InCal measurements. In stepwise regression analysis for developing new equations, the highest r2 (=0.89) was from a model comprising sex, height and weight. However, further analyses revealed that unlike the subjects under 30 y, the association between age and the measured RMR in subjects 30 y and plus was negative (r = −0.241, p = 0.001). As a result, two separate equations were developed for these two age groups. Over 80 percent of variations were covered by the new equations. In conclusion, there were statistical significant under- and over-estimation of RMR using common predictive equations in our subjects. Using the new equations, the accuracy of the calculated RMR increased remarkably.

Factor VIII-Related Activities in Normal, Haemophilic and von Willebrand’s Disease Platelet Fractions

1978 ◽  
Vol 40 (02) ◽  
pp. 288-301 ◽  
Author(s):  
P Meucci ◽  
I R Peake ◽  
A L Bloom
Keyword(s):  
Factor Viii ◽  
Electrophoretic Mobility ◽  
Concanavalin A ◽  
Freezing And Thawing ◽  
Von Willebrand's Disease ◽  
Factor Viii Related Antigen ◽  
Von Willebrand’S Disease ◽  
Normal Plasma ◽  
Significant Difference ◽  
Ristocetin Cofactor

SummaryFactor VIII-related activities have been studied in platelet fractions in order to try to reconcile the conflicting findings of other workers, and to extend the studies. In platelets from 16 normal subjects procoagulant factor VIII was not detected. The amount of factor VIII-related antigen (FVIIIR: AG) in the cytosol per mg of protein was about twice that in the membrane fraction and about ten times that in the debris fraction. There was no significant difference between the amount of FVIIIR: AG and ristocetin cofactor (RistCof) activity in each fraction. The findings in haemophilic platelets were similar. In von Willebrand’s disease (vWd) one serverely affected patient had no detectable factor VIII related activities in any platelet fraction. In 5 patients with intermediate vWd results were normal. In a further 5, with more prolonged bleeding times, no FVIIIR: RistCof was detected in platelets, despite a normal amount of FVIIIR: AG in the cytosol and debris. The electrophoretic mobility of cytosol FVIIIR: AG was increased in all normals and patients, while that in the membrane and debris fractions had normal mobility. Cytosol FVIIIR: AG eluted later than normal FVIIIR: AG on gel filtration on Sepharose 2B, and also showed reduced antibody binding in an immunoradiometric assay. Precipitation of FVIIIR: AG by concanavalin A was incomplete in all platelet fractions from normals, and even more reduced in vWd platelet fractions. The results suggest the possibility of two types of platelet FVIIIR: AG.A factor VIII-related antigen was shown to be associated with normal washed platelets by immunofluorescence techniques (Bloom et al. 1973). Since then, several studies have been reported on the localisation of factor VIII related antigen (FVIIIR: AG), factor VIII procoagulant activity (FVIII: C) and factor VIII related ristocetin cofactor activity (FVIIIR: RistCof) within the platelets. Initially, Howard et al. (1974) indicated that FVIIIR: AG was firmly bound to the platelet membrane, and noted that in lysed platelets the level of FVIIIR: AG as measured by electroimmunodiffusion was higher than that in whole platelet suspensions. However, further studies by Nachman and Jaffe (1975) showed that FVIIIR: AG was also present to a considerable extent in the granules, and they detected none in the platelet cytosol. Bouma and colleagues (1975) were, however, able to find FVIIIR: AG and FVIIIR: RistCof in the cytosol upon freezing and thawing platelets. This FVIIIR: AG had an electrophoretic mobility comparable to that of normal plasma. They also noted that platelets which were air dried apparently had a granular FVIIIR:AG localisation by immunfluorescence; however, intact platelets in suspension did not stain by this method.Recently Ruggeri et al. (1977) and Sultan et al. (1977) have also found FVIIIR: AG in the cytosol, and the former authors reported it to have increased electrophoretic mobility when compared to normal plasma FVIIIR:AG. Results concerning the localisation of FVIIIR: AG in normal platelets have thus been conflicting. Similarly, in the few reports available concerning platelet FVIIIR: AG in von Willibrand’s disease variable results have also been obtained (Ruggeri et al. 1977, Howard et al. 1974, Shearn et al. 1974 and Bouma et al. 1975).In this study we report on the localisation of factor VIII-related activities in normal, haemophilic and von Willebrand’s disease platelets using available standard techniques as well as precipitation of FVIIIR: AG with the plant lectin concanavalin A, a procedure which has been shown to detect abnormal forms of FVIIIR:AG in certain types of von Willebrand’s disease (Peake and Bloom 1977).

Assessment of Damage to Human Platelets after Aggregation and Other Injuries by Microscopic Observation and Estimation of Serotonin Uptake

1970 ◽  
Vol 23 (02) ◽  
pp. 261-275 ◽  
Author(s):  
G Zbinden ◽  
J. N Mehrishi ◽  
S Tomlin
Keyword(s):  
Platelet Aggregation ◽  
Electrophoretic Mobility ◽  
Human Platelets ◽  
Freezing And Thawing ◽  
Low Degree ◽  
Microscopic Evaluation ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Charged Macromolecules ◽  
5 Ht Uptake

SummaryThe severity of platelet damage induced by hyper- and hypotonic NaCl solutions and freezing and thawing was assessed by microscopic evaluation and measuring inhibition of 5-HT uptake. The same techniques were used to quantitate the effects of aggregating agents. The positively charged macromolecules PS, Poly-L und Poly-O reduced the net negative surface charge as determined by microelectrophoresis, caused platelet aggregation and inhibited 5-HT uptake. The damaging effects of Poly-L and Poly-O were more severe and more closely related to concentration than that of PS. The negatively charged macromolecules Poly-IC and NaPS increased the anodic electrophoretic mobility. Poly-IC and heparin caused a low degree of platelet clumping and no inhibition of 5-HT uptake. NaPS produced severe platelet damage with extensive clumping and complete inhibition of 5-HT uptake. Na laurate had the same effect, but did not alter electrophoretic mobility. ADP caused concentration-dependent platelet aggregation and inhibition of 5-HT uptake. The effects of ADP and NaPS were compared in agitated and non-agitated platelet samples containing identical concentrations of the 2 compounds. Agitation was found to increase the degree of platelet clumping and to reduce 5-HT uptake.

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