The invention provides compounds of formula, and pharmaceutically and agriculturally acceptable salts thereof: wherein: R1, R2, R3, R4, R5, R6, R7, R8, A1, L1 and n are as defined herein. The cleaning mechanism includes one or more cleaning tools, such as a brush and a wiper blade, and an onboard hydro-mechanical motor that provides the motive force for moving the cleaning mechanism. As a result, the liquid crystal composition containing the liquid crystal compounds can filter out light of specific wavelengths from incident light due to optical activity and high helical twisting power thereof. of the one user are made different to reality and the image data are transmitted to the another user in the communication. Heat energy generated by the at least one electronic system component raises a temperature of the first side and the cooling energy generated by the cooling medium lowers a temperature of the second side to establish a temperature difference.