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XIUsing XI

The XI tool consists of three sections, that are called consecutively. The first section is the selection of the chemical compound. The next section is to be used for the selection of the commodity, and its concentration(s), and the consumption days. Then the system will calculate the intake values, and report an overview of the results in the third section. Here it also provides you with the results of individual consumers for download.

Selection of a chemical substance

The system provides two ways to select a chemical substance. Its interface is identical to the EAST tool. The user selects how to proceed by means of two radio buttons []. The first radio button refers to a search field where a (part of a) name can be provided, to look for one or more chemicals in a database that meet yout input. E.g. input of Lead leads to a list with chemicals, including Lead (total) and Tetraethyl lead. For each a HBGV is given, with a link to the underlying document. Each finding is presented with radio buttons for the user to select the one to use.
For the second way, you have to provide the HBGV yourself. For this you have to provide the type of HBGV from a standard list, give the numerical value, and select the appropriate unit. A reference is optional. Beware: if you select the TWI (Tolerable Weekly Intake) or a similar type, the system will not check for the correct unit (per kg bodyweight per week in stead of per day).

Selection of a food commodity

The system provides also two ways to select a food commodity. The user selects how to proceed by means of two radio buttons []. The first radio button refers to a search field where a (part of a) name can be used to look for commodities that meet the name. E.g. input of Egg leads to a list with commodities, including Eggs, Egg white, Salad eggs, and more. These commodities are presented with radio buttons, and the user is asked to select one.
For the second way the system shows a list of major food-groups like Cereal products, Fish products, Meat and meat products, and more. Select a group, and press [Show Selection ]. Another list is then shown, with a selection of derived food-groups, e.g. from Fish products to Crustaceans and molluscs, Fish, Fish products, and more. Now you have two buttons [Show Commodities ] and [Use this Food Goup]. After pressing [Show commodities] various food-items will be shown, of which one should be selected. By pressing [Use this Food Group] however, all commodities that are part of that group will be used for the evaluation. As an example: Under Dairy products, cheese and ice you can select Yoghurt. [Use this Food Group] will select all yoghurt products. After [Show Commodities] you will see 24 different types of yoghurt, of which you have to select one, e.g. yoghurt low fat with fruit. In the latter case the system will use intake data for yoghurt low fat with fruit only.

Concentrations

After the selection of a food group or a commodity, XI will ask for the concentration of the chemical compound in the selected commodity or group. Here again you have two radio-buttons. First: give one value and select the appropriate unit. Or second: select a file with a series of concentrations for upload from your computer. This file should be a text file; each row should contain one value; there should not be empty lines between the different numbers. When using a program such as Microsoft Write or Excel to create that file, then you should use [Save As][Plain text (*.txt)] or [Text(MS-DOS)] to store the data in the correct format. The number of values is unlimited. Use decimal points, no commas. Text such as "n.d." or "#N/A" to represent a non detectable amount is not allowed and should be converted in a numerical value or be deleted from the file. Here you also have to select the correct unit; it should be the same for all values in the file.

Output

The system will provide you with a summary of the results of the calculations for the days you selected. It will show the number of consumers and non-consumers, and a median value and some percentiles. The percentiles are derived from the raw data, without any statistical approximations. Consequently, a percentile is only given if the number of values is sufficient large (e.g. for a 95-percentile you need at least 20 values). Besides the system will present a CSV file for download. This file contains all consumers, with a consumer_id, gender, its age and body weight, and the intake and intake per kg body weight, and test on the HBGV.
For more experienced users it is noted that the delimiter in this file is a semicolon (in stead of the comma). The semicolon is used by Microsoft Excel by default to read csv data. The file can then directly be imported in a spreadsheet program such as Excel, for further analysis. For import in other applications such as statistical software the delimiter might need to be converted, or specifically noted.

Tips and tricks

XI can evaluate one chemical substance in one food commodity only. The unique consumers_id makes it possible to import different output files together in a spreadsheet. After sorting these data using its consumer_id, you can perform additional calculations per row (i.e. consumer), e.g. the sum of intakes for different commodities to find "cumulative exposure".

If you are interested in the food intake for one or more selected commodities, without calculating the intake of a chemical substance in these commodities, one can also use the POCO tool. As that tool uses the same consumption data as XI does, the results are identical to a calculation with XI, using a "dummy" concentration of 1.

If you have found other ideas, and tips and tricks, for this XI tool which you would like to share with other participants, please send an email to the owner of this website.