Abstract: A process for producing catechins from tannic substance which has been extracted from tea leaves. An aqueous solution of the extract is admixed with an aqueous solution of caffeine to form a liquid-containing mixture of free catechins and a precipitated mixture of ester-type catechins. The caffeine is then removed from the aforesaid mixtures, and the respective mixtures fractionated to obtain epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate.

Abstract: Organopolysiloxane compositions are provided which are curable by condensation reaction taking place between a first component, hydroxy-terminated diorganopolysiloxane and a second component, organohydrogenpolysiloxane by aid of a third component, a condensation catalyst, and which are made to have their pot life extended by adding a fourth component, acyloxysilane, optionally in combination with a carboxylic acid, as a condensation retarder. The addition of the retarder does not adversely effect the curing velocity of the composition even at an elevated temperature and the properties of the cured composition.

Abstract: The accumulator chamber communicates with the atmosphere through a passage which is formed therein with a restriction for restricting the cross sectional area of the passage or which is provided therein with a pressure control valve for opening the passage in response to a difference between the atmospheric pressure and the vacuum in the accumulator chamber which difference is above a predetermined value to maintain the vacuum differential between the accumulator and vacuum chambers above a predetermined value when the engine suction vacuum is above a predetermined value.

Abstract: A plant viral disease inhibitor containing as an active ingredient thereof at least one material selected from the group consisting of theaflavin and its derivatives represented by the general formula: ##STR1## wherein R is hydrogen or ##STR2## and their analogues.