nmECx: Effect Concentration Calculation for J-shaped Models

In mixtox: Dose Response Curve Fitting and Mixture Toxicity Assessment

Effect Concentration Calculation for J-shaped Models

Description

Effect concentrations are calculated at particular effects based on the fitting coefficients of J-shaped Models.

Usage

nmECx(model, param, effv, minx, gap = -1e-6, sav = FALSE)

Arguments

model	a character vector of equations:("Brain_Consens", "BCV", "Biphasic", "Hill_five").
param	a numeric matrix of fitting coefficients with rownames (models) and colnames (ALpha, Beta, Gamma, Delta, and Epsilon).
effv	a numeric value (vector) with single or multiple effect values (miny ~ 1).
minx	a numeric value (vector) with single or multiple concentrations that induce maximun stimulation.
gap	theoritical response at the extreme low concentration predicted by a fitted model.
sav	TRUE: save output to a default file; FALSE: output will not be saved; a custom file directory: save output to the custom file directory.

Details

effect concentrations will be calculated with provided equations(model), associated fitting parameters (param), and effects (effv). Effect (effv) should be a value(s) between miny ~ 1. For example, effv should be 0.5 if we want to calculate a concentration causes 50% effect. minx should be calculated by curveFit or tuneFit.

Value

ecx	a numeric vector of effect concentration.

References

Zhu X-W, Liu S-S, Qin L-T, Chen F, Liu H-L. 2013. Modeling non-monotonic dose-response relationships: Model evaluation and hormetic quantities exploration. Ecotoxicology and Environmental Safety 89:130-136.

See Also

CEx curveFit

Examples

## example 1
# calculate ECL-10, ECR-10, EC5, and EC50 of the four hormetic curves 
model <- hormesis$sgl$model
param <- hormesis$sgl$param
minx <- hormesis$sgl$minx
nmECx(model, param, effv = c(-0.10, 0.05, 0.50), minx)

mixtox documentation built on June 20, 2022, 5:05 p.m.