Abstract: An ozonizer which comprises a flat hollow metal grounded electrode and a discharge electrode plate spaced apart therefrom by a discharge space. The discharge electrode plate includes a flat hollow dielectric member, a high voltage electrode formed on the inner surface of the dielectric member, a spacer material provided within and held in a clamped state by the dielectric member, a lead conductor provided within and held in a clamped state by the spacer material and a connector connecting the lead conductor and high voltage electrode.

Abstract: Novel maytansinoid compounds of the formula: ##STR1## wherein X is H or Cl, R.sup.1 is an alkyl group of 2 to 4 carbon atoms and R.sup.2 is a lower alkyl group or an unsubstituted or substituted phenyl or aralkyl group, have antimitotic, antitumor and antimicrobial activities.

Abstract: Novel maytansinoids of the formula: ##STR1## wherein X is H or Cl, and R is ##STR2## wherein R.sup.1 and R.sup.2 may be the same or different, and each is H or a substituted or unsubstituted hydrocarbon residue or heterocyclic group, or R.sup.1 and R.sup.2 may, taken together with the adjacent N atom, form a heterocyclic group, andR.sup.3 is a substituted or unsubstituted hydrocarbon residue, have antimitotic, antitumor and antimicrobial activities.

Abstract: Novel maytansinoids of the formula: ##STR1## wherein R.sup.1 is hydrogen atom, an alkyl group which may optionally be substituted or a group of the formula: --A.sup.1 --Y.sup.1 wherein A.sup.1 is an alkylene group or a bond, and Y.sup.1 is a cycloalkyl, phenyl, indolyl or imidazolyl group which may optionally be substituted,R.sup.2 is hydrogen atom, an alkyl, cycloalkyl or benzyl group,R.sup.3 is hydrogen atom, an alkyl group which may optionally be substituted, alkoxy, bornyloxy, isobornyloxy, benzyloxy group or a group of the formula: --A.sup.2 --Y.sup.2 wherein A.sup.2 is an alkylene group or a bond, and Y.sup.2 is an alicyclic hydrocarbon, phenyl or heterocyclic group which may optionally be substituted,provided that R.sup.3 is not an unsubstituted C.sub.1-4 alkyl group when both R.sup.1 and R.sup.2 are methyl groups, have antimicrobial antimitotic and antitumor activities.

Abstract: Novel dechloromaytansinoids of the formula: ##STR1## wherein R is H or acyl having 1 to 20 carbon atoms, have antimitotic, antitumor and antimicrobial activities.

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.

Abstract: Novel cephalosporins shown by the general formula: ##STR1## wherein Y is an acyloxy group, a quaternary ammonium group or a group of the formula: --S--R in which R is a nitrogen-containing heterocyclic group, and pharmaceutically acceptable salts thereof have high antibacterial properties against Gram-positive and Gram-negative bacteria including Pseudomonas aeruginosa and Serratia marcescens.

Abstract: Novel penicillins of the formula ##STR1## wherein R is a branched chain alkyl group of from 3 to 14 carbon atoms, and their pharmaceutically acceptable salts, are easily absorbed in the blood and tissues through oral administration and show excellent antimicrobial activity against Gram-positive and Gram-negative bacteria, particularly against microorganisms of the genus Pseudomonas, such as Pseudomonas aeruginosa.

Abstract: Novel d-.alpha.-isobutylsulfobenzylpenicillin hemi-solvate crystals of the formula: ##STR1## (wherein A is a solvent selected from the class consisting of alcohols, ketones, ethers and esters) have excellent antibacterial activities and improved stability in terms of shelf-life.

Abstract: .alpha.-Sulfophenylacetic acid derivatives of the general formula: ##STR1## (wherein R is a substituted or unsubstituted primary alcohol, cyclic alcohol or phenol compound residue), which are of value as intermediates of antibacterial agents, are selectively produced in a high yield by bringing a diester compound of the general formula: ##STR2## (wherein R has the same meaning as defined above) into contact with a strong acid.

Abstract: .alpha.-Sulfophenylacetic acid derivatives of the general formula: ##EQU1## (wherein R is a substituted or unsubsituted primary alcohol, cyclic alcohol or phenol compound residue), which are of value as intermediates of antibacterial agents, are selectively produced in a high yield by bringing a diester compound of the general formula: ##EQU2## (wherein R has the same meaning as defined above) into contact with a strong acid.