Abstract: This invention relates to a novel 4'-demethyl-4-epipodophylltoxin derivative of the formula: ##STR1## (wherein R.sub.1 is a lower alkyl group; X.sub.1 and X.sub.2 are each a hydroxyl group or an amino group substituted by one or two lower alkyls, provided that either one of X.sub.1 and X.sub.2 is an amino group substituted by one or two lower alkyls and the other is a hydroxyl group) and salts thereof.

Abstract: This invention relates to novel 4'-demethyl-4-epipodophyllotoxin derivatives represented by the general formula (I), and salts thereof: ##STR1## wherein R is a lower alkyl group, and X.sub.1 and X.sub.2 are independently a hydroxyl group or an amino group, the one being an amino group and the other being a hydroxyl group. These novel derivatives have a high carcinostatic activity and a relatively high water solubility and hence are expected to be useful as carcinostatics.

Abstract: A damper disc applicable to a friction clutch disc, wherein each side plate is arranged between each sub-plate and a flange of a hub splined on an output shaft, so that a distance between both side plates becomes small, and the side plates can stably support the portions of the torsion springs which are adjacent to the center thereof, in other words, portions adjacent to the flange, and thereby high stability in the twisting operation can be obtained.

Abstract: The present invention relates to a damper disc suitable for large and heavy-duty friction clutch discs. The damper disc comprises a hub splined to an output shaft; axially spaced two or more annular flanges rotatably fitted to the outer periphery of the hub; annular side plates arranged at both sides of each flange; torsion springs extending substantially in the disc rotating direction and disposed in openings formed in the flanges and the side plates, each pair of the side plates being connected to the adjacent flange by the torsion springs; a torque input member connected to the flanges; one of each side plates pair being connected to the hub.

Abstract: A damper disk comprises a pair of side plates at both sides of a flange of a hub splined to an output shaft. Both side plates and the flange are connected each other through torsion springs. One or a pair of sub-plates are disposed between the flange and the side plates. Both side plates are connected together by a stop pin which extends through notches in the flange and the sub-plates. The notches in the sub-plates are shorter than the notch in the flange. Frictional force between the flange 2 and the sub-plate is set stronger than that between the side plates and sub-plates. According to the invention, hysteresis torque changes during torsional operation, thereby, noises during idling of the engine as well as acceleration can be prevented.