Abstract: Compounds useful in the treatment of Alzheimers's disease, senile dementia or memory disorders of the aged of the formula ##STR1## in which n represents the number 1, 2 or 3,R.sub.1 and R.sub.2, identical or different, represent hydrogen, a linear, branched or cyclic alkyl, alkenyl, or alkynyl which contain up to 6 carbon atoms, R.sub.1 and R.sub.2 optionally substituted by hydroxy, alkoxy containing up to 6 carbon atoms, aralkyl containing up to 14 carbon atoms, a COOalk.sub.1 radical in which alk.sub.1 represents alkyl containing up to 6 carbon atoms, a --CON(alk.sub.2).sub.2 radical in which alk.sub.2 represents alkyl containing up to 6 carbon the radical --C(R.sub.1).dbd.NOR.sub.2 being in position 2, 3 or 4, in all their isomer forms and their mixture, as well as their addition salts with pharmaceutically acceptable organic or mineral acids. Also therapeutic compositions containing the compounds, method of treatment and method of preparation.

Abstract: A compound which is represented by a free acid of the following formula, ##STR1## wherein X is hydrogen, halogen, alkyl or cyano, R.sub.1, R.sub.2 and R.sub.3 are independently hydrogen or alkyl, R.sub.4 is alkyl, W is alkylene, cycloalkylene or arylene, Q is --SO.sub.2 CH.dbd.CH.sub.2 or --SO.sub.2 CH.sub.2 CH.sub.2 L in which L is a group capable of being splitted by the action of an alkali, D is a benzene or naphthalene ring, l and m are independently a number of not less than 0 but not more than 3, and n is a number of more than 0 but not more than 3, provided that l, m and n satisfy 0<l+m+n.ltoreq.4, and which is useful for dyeing fiber materials a blue color with a good build-up property to give a dyed product having excellent fastness properties.

Abstract: The invention relates to a transducer for the micrometric measurement of linear quantities comprising a support rule, a scale in the form of a very thin continuous metal tape which is kept suspended at its ends under a predetermined constant tension and on which the measurement notches are directly engraved, and a reading head comprising a tape guide groove in which the tape slides freely during the movement of the head relative to the support rule.

Abstract: Novel maytansinoids of the formula: ##STR1## wherein R is an alicyclic hydrocarbon group of 3 to 10 carbon atoms, phenyl or heterocyclic group, which may optionally be substituted, andA is an alkylene group of 1 to 4 carbon atoms or a bond, provided that A means said alkylene group when attached to a N atom in said heterocyclic group R,have antimicrobial, antimitotic and antitumor activities.