mixtox (version 1.0)

ECx: Effect Concentration Calculation

Description

Effect concentrations are calculated at particular effects based on the fitting coefficients of six equations (Hill, Weibull, Logit, BCW, BCL, GL)

Usage

ECx(model, param, effv)

Arguments

model

character vector of equations: Hill, Weibull, Logit, BCW, BCL, GL

param

numeric matrix of fitting coefficients with rownames (equation selected) and colnames (ALpha, Beta, and Gamma).For equations with two parameters, Gamma can be set as zero or any other numeric value.

effv

numeric vector with single or multiple effect values (0 ~ 1)

Value

• a numeric vector of effect concentration(s)

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 0~1. For example, $effv$ should be 0.5 if we want to calculate a concentration causes 50% effect.

References

Hill equation (biochemistry) http://en.wikipedia.org/wiki/Hill_equation_(biochemistry) Scholze, M. et al. 2001. A General Best-Fit Method for Concentration-Response Curves and the Estimation of Low-Effect Concentrations. Environmental Toxicology and Chemistry 20(2):448-457.

See Also

CEx

Examples

data(cytotox)
## example 1
# calculate EC50 of heavy metal Ni(2+) on the MCF-7 cells
model.ni <- cytotox$sgl$model
param.ni <- cytotox$sgl$param
ECx(model.ni, param.ni, effv = 0.5) 

## example 2
# calculate EC5 and EC50 of four heavy metals and four ionic liquids on the MCF-7 cells
model <- cytotox$sgl$model
param <- cytotox$sgl$param
ECx(model, param, effv = c(0.05, 0.50))