Abstract: A 1,4-dihydropyridine derivative of the formula ##STR1## wherein R.sup.1 and R.sup.2 are identical or different and each represents a hydrogen atom, a halogen atom or a nitro group, provided that R.sup.1 and R.sup.2 are not hydrogen atoms at the same time; R.sup.3 represents an alkyl group; R.sup.4 represents an aralkyl group which may be substituted; R.sup.5 and R.sup.7 are indentical or different and each represents an alkyl group; R.sup.6 represents a hydrogen atom or an alkyl group; R.sup.8 represents an alkyl group; R.sup.9 represents a hydrogen atom or an alkyl group; n and m are identical or different and each represents an integer of 0 to 6; provided that when either one of R.sup.1 and R.sup.2 is a hydrogen atom, R.sup.9 is an alkyl group;or an acid addition salt thereof.The 1,4-dihydropyridine derivative is characterized by a strong antihypertensive activity and the long duration of the activity.

Abstract: Cooling water containing an .alpha.-amino acid suitable for cooling steel strips during their continuous annealing and after their overageing treatment. As the .alpha.-amino acid, aliphatic amino acids, aromatic amino acids, heterocyclic amino acids and their hydrochlorides and acetates are used.

Abstract: A lens cap has a disc-shaped cap body, a pair of sliding members opposed to each other on the cap body and slidable diametrically of the cap body, and a biasing member for biasing the sliding members in a direction in which they are extended outwardly from the cap body. The sliding members have connecting portions engageable with a connecting portion provided on the inner peripheral surface of the rim of a lens barrel. The lens cap is mounted on the lens barrel by engagement between the connecting portions. Engaging members are provided at the opposed ends of the sliding members and limit the outward extension of the sliding members from the cap body against the biasing means by mutual engagement therebetween.

Abstract: In a camera lens barrel having a stationary barrel and a distance ring, a click stop device comprises a ring for setting the restrained position of the distance ring disposed on the stationary barrel with a predetermined clearance with respect to the distance ring, a screw manually operable to fix the set ring to the stationary barrel at any desired position, and a pair of click stop means provided between the distance ring and the set ring so as to engage each other within the clearance.

Abstract: A tetrahydro-1,3,5-thiadiazin-4-one represented by the general formula, ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3, which may be the same or different, represent each an alkyl group, allyl group, cycloalkyl group, alkoxyalkyl group, benzyl group, phenyl group or substituted phenyl group having as substituents alkyl groups, nitro group, halogen atoms, alkoxy groups, or trifluoromethyl group and R.sup.2 and R.sup.3 may also represent hydrogen atoms, is a new compound and useful for controlling insects and mites.