Software: Computer Algorithms Implemented:

            Sielken & Associates develops software primarily for internal and client use and does not for distribute software for sales purposes.

Dose-Response Modeling Tools:

1. A GENeral Tool for incorporating dose-response modeling and extrapolation techniques into quantitative cancer and noncancer risk assessments.  Includes essentially all current dose-response models for high-to-low-dose extrapolation and benchmark dose determination.  Can reflect response-frequency data, time-to-response data, user-specified target site doses (delivered, PBPK, and biologically effective doses), age-dependent doses and model parameters, cell proliferation, species and route extrapolations, and individual variability in background doses and susceptibility.
                       GEN.T
   
    
2. An epidemiological tool similar to GEN.T but with the added capability of handling observed data with each individual having his own distinctive age‑dependent exposure pattern.
                       EPID.T
   
    
3. Physiologically‑based pharmacokinetic modeler of the time‑dependent delivered doses corresponding to user‑specified parameterizations of a flow‑limited, multicompartment body undergoing inhalation, intravenous, or oral exposure.
                       PBPK Modeler
   
   
4. Utilizes a historical data base, compares animal-based predictions with human data, and generates empirical weights for weight-of-evidence analyses.
                       EXTRACT
   
    
5. Two-stage growth model of carcinogenesis incorporating the effects of dose, time, and the relative sensitivity of subtissues.  Implementation of the solutions to the Kolmogorov-Fokker-Planck equation which is an expression of the Moolgavkar/Venzon/Knudson model for independent subpopulations of cells and time-dependent (step-function) growth parameters.
                       MVK/KFP Modeler
   
   
6. Monte Carlo simulator of the two-stage growth process of carcinogenesis. Implementation of Monte Carlo simulation of cell division, death or differentiation, and mutation for tissues or organs in which the opportunities for cellular events (birth, death, mutation) are periodic.
                       2SGM/MC Simulator
   
   
7.  Statistical Methodology for Toxicological Research predecessors to GEN.T.
                       a.         MRS. T
                       b.         MRS. T81
                       c.         MRS. T81B