To convert your crude extract into a concentration of 400 ug/mL for your research on α-glucosidase activity, you will need to determine the current concentration of your extract. Once you have this information, you can calculate the volume of your crude extract needed to achieve the desired concentration. For example, if your crude extract concentration is 800 ug/mL, you would dilute it by adding an equal volume of a suitable diluent (e.g., water or buffer) to obtain a concentration of 400 ug/mL. Alternatively, if your crude extract concentration is higher or lower than 800 ug/mL, you can adjust the volume accordingly to achieve the desired concentration of 400 ug/mL. It is crucial to ensure accurate measurements and proper mixing during the dilution process to achieve reliable results for your α-glucosidase activity research.