Abstract: In a UV laser system, the problem of deposition of residues of organic substances on the surfaces of optical components is avoided so that the reduction in the laser output can be avoided. A wavelength converting crystal (10) used for the generation of a UV laser light is provided with a reflective plane (14) that selectively reflects the UV laser light (23) to cause the UV laser light to emit from a part of the wavelength converting crystal different from an optical path of a basic wavelength laser light (21). The residues may be deposited on the part of the wavelength converting crystal from which the UV laser light is emitted, but not in the part of thereof through which the basic wavelength laser light passes so that the generation process for the UV laser light is not affected by the deposition of the residues.

Abstract: A horizontally elongated laser beam is divided into a plurality of beam sections which are arranged along the horizontal direction and vertically deflected to different degrees by a beam deflecting beam guide, and the beam sections leaving the beam deflecting beam guide at different vertical positions are horizontally deflected by a beam converging beam guide to different degrees so that the beam sections may converge along a vertical line, and the laser beam which was initially laterally elongated may be shaped into a more circular cross section which is desirable for pumping a laser system and other applications. Each of the beam guides may consist of a plurality of transparent plate members which are placed one over the other, and each beam segment is conduct through a corresponding one of the plate member along a path parallel to the major surface of the plate members.

Abstract: The present invention provides novel dihydrate crystals of etoposide-2-dimethylamino compound hydrochloride [4'-demethylepipodophillotoxin 9-(4,6-O-ethylidene-2-dimethylamino-2-deoxy-.beta.-D-glucopyranoside hydrochloride] used as a carcinostatic agent and a process for production thereof.

Abstract: This invention relates to the novel selenium compounds which are useful as an antineoplastic agent. The compounds are represented by the general formula (I):Se(O).sub.a (R).sub.b (X).sub.c (A).sub.n (Y).sub.m (I)wherein R, X, A and Y represent the groups specified below, a represents a number of 0 or 1, b represents a number of 0, 1 or 2, and (1) when a is 0 and b is also 0, c is 4, n is 1 or 2 and m is 0, (2) when a is 1 and b is 0, c is 2, n is 1 or 2 and m is 0 or 1, and (3) when b is 1 or 2, c, n and m are all 0;(i) when b is 2, R represents (1) a C.sub.4-10 alkoxy group substituted with a halogen atom, (2) a lower alkoxyl group substituted with a halogen atom and a phenyl group, or (3) a cycloalkyloxy group substituted with a halogen atom, and (ii) when b is 1, R represents a group represented by the formula ##STR1## (wherein R.sub.0 is a C.sub.2-6 alkyl group); X represents a halogen atom;A represents a compound represented by the formula ##STR2## (wherein R.sub.1 and R.sub.