Abstract: Systems and methods for use with a biological sample include a microscopy device, a diluent, a sample holder, and one or more of lyophilized cakes comprising artificial particles. The lyophilized cakes and the biological sample are mixed with the diluent in the sample holder to form a solution. The biological sample is imaged with the artificial particles as reference markers using the microscopy device. A settling time of the artificial particles is shorter than or equal to a settling time of the biological sample.

Abstract: An eye protecting mask of a video display comprises a frame and an adjustment device. The frame is provided centrally in the top side thereof with a recessed portion which is provided respectively in the inner walls of two sides thereof with a predetermined number of retaining slots and with an opening adjacent to the retaining slots. The adjustment device comprises a base and a pivoting member capable of swiveling on a pivot and corresponding in location to the recessed portion of the frame. The pivoting member is provided respectively at both ends thereof with a retaining portion and a cut adjacent to the retaining portion. The pivoting member is fitted into the recessed portion of the frame such that the two retaining portions of the pivoting member are engaged with the retaining slots of the frame so as to locate properly the eye protecting mask in front of the video display.