3.5.    Displaying Results

3.5.1.   Introduction

This section deals with the display of results from the GENTEX model. Five types of results are available: heterogeneity ( Section 3.5.2), Tracer and nontracer concentrations ( Section 3.5.3), tissue contents or residues ( Section 3.5.4), residuals ( Section 3.5.5), and user defined parameter expressions ( Section 3.5.6). The final part of this section deals with errors and messages related to display of results.

3.5.2.    Heterogeneity results

The parameters that contain the heterogeneity results are shown in the Flow heterogeneity results window.

See Section 3.3.2 for the definitions of the parameters shown in Fig. 3.5.15

The Flow histogram parameters and the Pathway flows and weights are loaded with single values at the end of the simulation run. The Heterogeneity plot outputs that have a shaded field background are dynamic parameters that are set at each step of the model solution. Scaling and display of these outputs are discussed in Section 3.3.2.

3.5.3.    Tracer and nontracer concentrations

Introduction

The parameters that contain the tracer and nontracer concentrations at the inlet and outlet of the organ are shown in Table 3.5.16. Tracer and nontracer concentrations at the inlet and outlet of individual operators and inside the BTEX unit are also available.

GENTEX allows up to five permeant species. The list here includes only species #1.

Organ inflow concentrations

Parameters Cin_r, Cin_v and Cin_e contain the inflow concentrations of the three reference tracers. For permenat species, the inflow concentrations can be of tracer or nontracer, can be free or bound to a moving binding site, and can be in RBC's, in plasma or in the whole blood. See Fig. 3.5.16 for details. These concentrations result from the input function generation discussed in Section 3.2 and are delivered to the upstream end of the inlet tubing.

Organ outflow concentrations

Parameters Cout_r, Cout_v and Cout_e contain the outflow concentrations of the three reference tracers. For permenat species, the outflow concentrations can be of tracer or nontracer, can be free or bound to a moving binding site, and can be in RBC's, in plasma or in the whole blood. See Table 3.5.16 for details. These concentrations are measured at the downstream end of the outlet tubing. The organ inflow and outflow concentrations of reference tracers can be viewed in the Concentrations by species window (Parameters: Model outputs> Reference tracer inflow & outflow). The organ inflow and outflow concentrations of permenat species can be viewed in the Concentrations by species window (Parameters: Model outputs> Concentrations by species).

Outflow concentrations by operators

The outflow concentrations from any operators can be viewed in the Outflow concentrations by operators window ( Fig. 3.5.16; Parameters: Model outputs > Concentrations by operators). Users can select the operator, the path, the tracer type, and the species. The output variables are

Concentrations in BTEX regions

The concentrations of permeant species in the capillary-tissue unit can be viewed in the Concentrations in BTEX unit by user choice window ( Fig. 3.5.17; Parameters: Model outputs>Concentrations in BTEX unit by user choice ). Users can select species, tracer type, path, a specific segment or averaging on all segments, and two different BTEX regions. There are two sets of output variables each for one region. Listed in the folllowing table are the set of variables for region #1.

3.5.4.    Tissue contents (residues)

Introduction

The amount of tracer in the organ, or region of the organ, is denoted by the letter Q (quantity). In GENTEX, the residues are calculated in two ways: (1) summing up all the amount in the user-specified volume; (2) integrating the inflow and outflow curves from the whole models (Fick method).

Residues in user-specified volumes

Users can specify one volume for reference tracer contents by using the Reference tracer content by user choice window (Parameters: Model outputs > Reference tracer contents by user choice); and two volumes for permenat species contents by using the Permenat contents by user choice-1(2) window ( Fig. 3.5.18; Parameters: Model outputs > Permenat contents by user choice-1(2)). Users can select species, path, BTEX regions, and operators to be included in the calculation.

The output variables are

Whole organ residues

The whole organ residues for the reference tracers can be viewed in the Contents by Fick window (Parameters: Model outputs> Contents by Fick). The output variables are

3.5.5.    Residuals

Introduction

In contrast to residue curves, residuals are the difference between a model curve and a data curve:.

Note that the residuals are not normalized and may be either positive or negative. Values of the residual are only calculated at each point in the data curve.

Residual curve parameters

To create a residual curve graph ( Fig. 3.5.19, top), first make sure that a reference data TAC file has already been loaded into XSIM, then select Residuals config from the Model pull-down menu. Fill in the desired reference data curve name(s) and the parameter name(s) that you wish to compare ( Fig. 3.5.20), and enter `1' for the point weights and TAC weights if equal weighting is desired (See section 8.2.4 of the Interface Reference Manual for a discussion of weighting options). Click on the Residuals button in the main window and a Residual Plot window should appear.  

3.5.6.    Parameter expressions and scalars

User defined expressions of parameters may be plotted in either of the plot area windows. For example, the parameter of Cout_v in the previous section may be scaled by 0.5, and offset from zero by 0.1, as in Fig. 3.5.21. See Appendix B of the XSIM manual for a listing of the expressions evaluator constants and functions.

If a constant will be used repeatedly and/or often, a scalar may be useful. The set of scalars are simply a set of parameters that are not tied to the model, but can be set like any other parameter, either by entering a value directly or by slaving the scalar to another parameter in the eval field. Scalars are accessed from the Parameters pull-down menu.

In the example of Fig. 3.5.22, scalar1 has been set to 0.5. One could substitute `scalar1' for 0.5 in the Y parameter field shown in figure 3.8, making the equation Cout_v*scalar1+0.1. This scalar could then be optimized on by placing scalar1 in the parameters to vary section of the optimization config window.

Also shown in Fig. 3.5.22 is an example of using the eval field to make scalar4 equal the ratio of extracellular PSg to flow, Fp.

3.5.7.   Errors and messages

[TO BE DEVELOPED]

3.6.   Summary