There is provided a container having both male and female sealing regions disposed about its periphery in a pattern making it possible to seal a container with another container having substantially identical sealing regions. In various embodiments, the present teachings provide ion sources, methods for focusing ions from an ion source, and methods for operating a time-of-flight mass analyzer. The moving web is wrapped around a portion of the rotatable backing roller with the rotatable backing roller supporting the moving web through a dynamic wetting line. The images are calibrated with a variety of reference materials and displayed in a variety of measurement units. The invention also relates to processes for preparing amorphous losartan potassium and pharmaceutical compositions that include the amorphous losartan potassium.