scholarly journals Analysis of kinetic data for irreversible enzyme inhibition

1989 ◽  
Vol 257 (2) ◽  
pp. 419-424 ◽  
Author(s):  
P J Gray ◽  
R G Duggleby

Many organophosphorus compounds are irreversible inhibitors of acetylcholinesterase. The methods used in the literature to determine the inhibition kinetic constants usually involve either manual determination of the slope at various points along the inhibition progress curve or fitting polynomials to the curve. The present study investigates the use of non-linear-regression analysis to determine the various parameters. A method is suggested that yields accurate values for the inhibition constants under a range of circumstances.

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Rahel Jedamski ◽  
Jérémy Epp

Non-destructive determination of workpiece properties after heat treatment is of great interest in the context of quality control in production but also for prevention of damage in subsequent grinding process. Micromagnetic methods offer good possibilities, but must first be calibrated with reference analyses on known states. This work compares the accuracy and reliability of different calibration methods for non-destructive evaluation of carburizing depth and surface hardness of carburized steel. Linear regression analysis is used in comparison with new methods based on artificial neural networks. The comparison shows a slight advantage of neural network method and potential for further optimization of both approaches. The quality of the results can be influenced, among others, by the number of teaching steps for the neural network, whereas more teaching steps does not always lead to an improvement of accuracy for conditions not included in the initial calibration.


2020 ◽  
Vol 6 (8) ◽  
pp. 1607
Author(s):  
Dian Anggraini ◽  
Imron Mawardi

The purpose of this study is to analyze the factors that affect the profitability of Sharia Commercial Bank in Indonesia. The sampling technique used is saturated sampling, so the population and sample is the Sharia Commercial Bank periode October 2014-March 2018 which amounted to 42 months. This study uses a quantitative approach with multiple linear regression analysis technique.The result showed that with 95% confidence level partially variable Financing to Deposit Ratio have significant effect to profitability, while variable Natural Uncertainty Contract Financing, Non Performing Financing, and Equity have no significant effect on profitability of Sharia Commercial Bank in Indonesia. Nevertheless, Natural Uncertainty Contract Financing, Non Performing Financing, Financing to Deposit Ratio and Equity simultaneously have significant effect to the profitability of Sharia Commercial Bank in Indonesia. With the coefficient of determination of 33,2%.Keywords: Natural Uncertainty Contract, Non Performing Financing, Financing to Deposit Ratio, Equity


2019 ◽  
Vol 10 (12) ◽  
pp. 21683-21692
Author(s):  
Sapta Rini Widyawati ◽  
I Dewa Made Adnyana ◽  
I Nyoman Mustika

This study aims to determine the effect of compensation and job promotions on employee job satisfaction at PT. Permata Jaga Karya, Denpasar. The number of research samples were 84 employees. Determination of the sample using saturated or census means that all employees are respondents. The analytical tool used is multiple linear regression analysis with the help of SPSS version 23.0. The results of the analysis showed that compensation had a significant positive and significant effect on employee job satisfaction at PT. Permata Jaga Karya, Denpasar, this is evidenced by the value of the coefficient B for X1 is positive and the significant value of t (X1) <0.05. Similarly, promotion has a significant positive and significant effect on employee job satisfaction at PT. Permata Jaga Karya, Denpasar, this is evidenced by the value of the coefficient B X2 is positive and the significant value of t (X2) <0.05.


1985 ◽  
Vol 31 (4) ◽  
pp. 605-608 ◽  
Author(s):  
P L Cary ◽  
C A Johnson ◽  
P D Whitter ◽  
J W Parker

Abstract Determination of cholesterol by a radiative energy attenuation (REA) technique was evaluated and compared with results obtained by the Boehringer Mannheim High Performance Cholesterol Assay and the Du Pont aca. Within-assay and between-assay CVs for the REA method, for two sets of controls, were both less than 5%. We observed no interference with lipemic samples. Analytical recovery averaged 102.8%. We used all three methods for parallel determinations of 217 patients' samples containing a wide range of cholesterol concentrations. Linear regression analysis of the REA results vs those of the comparison methods were as follows: REA = 1.03 Boehringer - 0.072 (r = 0.993) and REA = 1.02 aca - 0.048 (r = 0.995). We also discuss bilirubin interference with the REA method for cholesterol.


2012 ◽  
Vol 66 (7) ◽  
Author(s):  
Marta Ambrová ◽  
Jana Jurišová ◽  
Pavel Fellner ◽  
Jomar Thonstad

AbstractSolidified cryolite melts containing a known amount of Na2SO4 (0–713 mg kg−1 SO42−), Na2S, FeS, and CdS (0–400 mg kg−1 S2−) together with industrial electrolyte samples were tested for the content of sulphate and sulphide ions by ion chromatography. Added and analytically determined contents of sulphate and sulphide were compared and processed by means of linear regression analysis. It was found that the method of ion chromatography yields satisfying results (uncertainty below 1.1 %) and that it is especially suitable for the determination of low content of soluble sulphate or sulphide in solidified cryolite electrolytes. The method can be used for the estimation of insoluble sulphide content in cryolite melts as well. Results of industrial samples analysis showed that the content of sulphate and sulphide in the samples is influenced by their treatment before the analysis.


1985 ◽  
Vol 228 (1) ◽  
pp. 55-60 ◽  
Author(s):  
R G Duggleby

Most methods for studying the kinetic properties of an enzyme involve the determination of initial velocities. When the reaction progress curve shows significant curvature due to depletion of the substrate, accumulation of inhibitory products or instability of the enzyme, estimation of the initial velocity is a subjective and inexact process. Two methods have been suggested [Cornish-Bowden (1975) Biochem. J. 144, 305-312; Boeker (1982) Biochem J. 203, 117-123] that attempt to eliminate this subjective element. The present study offers a third alternative, which is based on fitting a reparameterized form of the integrated Michaelis-Menten equation to the progress curves by non-linear regression. This method yields estimates and standard errors of the initial velocity and of the time to reach 50% reaction. No prior knowledge of the apparent product concentration at zero time or infinite time is required, since both of these quantities are also estimated from the data. It is shown that this method yields reliable estimates of the initial velocity under a wide range of circumstances, including those where the two previously published methods perform poorly.


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