scholarly journals Erythrocyte transketolase activity coefficient (ETKAC) assay protocol for the assessment of thiamine status

2020 ◽  
Author(s):  
Kerry S. Jones ◽  
Damon A. Parkington ◽  
Lorna J. Cox ◽  
Albert Koulman
Keyword(s):  
Activity Coefficient ◽  
Transketolase Activity ◽  
Assay Protocol

Effect of association in the vapour phase on the value of activity coefficient

1979 ◽  
Vol 44 (4) ◽  
pp. 1187-1196 ◽  
Author(s):  
Ivona Malijevská
Keyword(s):  
Activity Coefficient ◽  
Binary Systems ◽  
Vapour Phase

The relations were obtained between the thermodynamically consistent activity coefficient of associating component and the activity coefficient calculated irrespective of the association in the vapour phase. The analysis is limited to binary systems with one associating component and is given for the two cases: (a) the associating component dimerizes only, (b) the associating component forms, in addition to a dimer, one higher associate, too.

scholarly journals Ag nanoparticles outperform Au nanoparticles for the use as label in electrochemical point-of-care sensors

2021 ◽  
Author(s):  
Franziska Beck ◽  
Carina Horn ◽  
Antje J. Baeumner
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Automatic Measurement ◽  
High Sensitivity ◽  
Differential Pulse ◽  
Small Sample ◽  
Blood Protein ◽  
User Friendliness ◽  
Response Curves ◽  
Assay Protocol

AbstractElectrochemical immunosensors enable rapid analyte quantification in small sample volumes, and have been demonstrated to provide high sensitivity and selectivity, simple miniaturization, and easy sensor production strategies. As a point-of-care (POC) format, user-friendliness is equally important and most often not combinable with high sensitivity. As such, we demonstrate here that a sequence of metal oxidation and reduction, followed by stripping via differential pulse voltammetry (DPV), provides lowest limits of detection within a 2-min automatic measurement. In exchanging gold nanoparticles (AuNPs), which dominate in the development of POC sensors, with silver nanoparticles (AgNPs), not only better sensitivity was obtained, but more importantly, the assay protocol could be simplified to match POC requirements. Specifically, we studied both nanoparticles as reporter labels in a sandwich immunoassay with the blood protein biomarker NT-proBNP. For both kinds of nanoparticles, the dose-response curves easily covered the ng∙mL−1 range. The mean standard deviation of all measurements of 17% (n ≥ 4) and a limit of detection of 26 ng∙mL−1 were achieved using AuNPs, but their detection requires addition of HCl, which is impossible in a POC format. In contrast, since AgNPs are electrochemically less stable, they enabled a simplified assay protocol and provided even lower LODs of 4.0 ng∙mL−1 in buffer and 4.7 ng∙mL−1 in human serum while maintaining the same or even better assay reliability, storage stability, and easy antibody immobilization protocols. Thus, in direct comparison, AgNPs clearly outperform AuNPs in desirable POC electrochemical assays and should gain much more attention in the future development of such biosensors.

Revisiting the Classic Activity Coefficient Models

2021 ◽  
Author(s):  
Walter W. Focke ◽  
Stefan Endres ◽  
Elizabeth L. du Toit ◽  
Mattheüs T. Loots ◽  
Roelof L. J. Coetzer
Keyword(s):  
Activity Coefficient ◽  
Activity Coefficient Models

Overview of Activity Coefficient of Thiophene at Infinite Dilution in Ionic Liquids and their Modeling Using COSMO-RS

2016 ◽  
Vol 55 (3) ◽  
pp. 788-797 ◽  
Author(s):  
Pranesh Matheswaran ◽  
Cecilia Devi Wilfred ◽  
Kiki A. Kurnia ◽  
Anita Ramli
Keyword(s):  
Ionic Liquids ◽  
Activity Coefficient ◽  
Infinite Dilution

Erythrocyte transketolase activity in uremia

1980 ◽  
Vol 108 (2) ◽  
pp. 169-177 ◽  
Author(s):  
Kuriyama Masaru ◽  
Mizuma Atsumi ◽  
Yokomine Ryoko ◽  
Igata Akihiro ◽  
Otuji Yoshito
Keyword(s):  
Transketolase Activity

On the Calculation of Transition State Activity Coefficient and Solvent Effects on Chemical Reactions

1998 ◽  
Vol 63 (12) ◽  
pp. 1969-1976 ◽  
Author(s):  
Alvaro Domínguez ◽  
Rafael Jimenez ◽  
Pilar López-Cornejo ◽  
Pilar Pérez ◽  
Francisco Sánchez
Keyword(s):  
Activity Coefficient ◽  
Transition State ◽  
Chemical Reactions ◽  
Solvent Effects ◽  
Transition State Theory ◽  
Reaction Medium ◽  
State Theory ◽  
Precursor Complex ◽  
State Activity ◽  
Classical Transition

Solvent effects, when the classical transition state theory (TST) holds, can be interpreted following the Brønsted equation. However, when calculating the activity coefficient of the transition state, γ# it is important to take into account that this coefficient is different from that of the precursor complex, γPC. The activity coefficient of the latter is, in fact, that calculated in classical treatments of salt and solvent effects. In this paper it is shown how the quotients γ#/γPC change when the reaction medium changes. Therefore, the conclusions taken on the basis of classical treatments may be erroneous.

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