Abstract: 2-Amino-4-hydroxy-4,5,6,7-tetrahydropyrido?2,3-d!pyrimidine derivatives of aromatic amides, such as a benzamide or thienylcarboxamide in which the amino portion of the amide is other than L-glutamic acid are inhibitors of enzymes which utilize folic acid, in particular glycinamide ribonucleotide formyl transferase. A typical embodiment is N-(N-{4-?2-(2-amino-4-hydroxy-5,6,7,8-tetrahydropyrido?2,3-d!pyrimidin-6-y l)ethyl!benzoyl}-L-.gamma.-glutamyl)-D-aspartic acid.

Abstract: A vapor generator in which a plurality of tubes are connected together and arranged to form at least a portion of the boundary walls of a gas-tight enclosure. Portions of the tubes are bent to form a plurality of openings extending through at least one of the boundary walls. Some of the bent tube portions extend around the openings in the plane of the wall, and others of the bent tube portions extend out of the plane of the wall. The tubes, including the bent portions, extend at an angle with respect to a horizontal plane for their entire lengths to enable the tubes to drain. A burner is associated with each opening to apply heat to the enclosure, and fluid is passed through the tubes to apply heat to the fluid.

Abstract: A vapor generator including an upright furnace section the boundary walls of which are formed by a plurality of tubes, a portion of which extend at an angle with respect to a horizontal plane. A plurality of divisional walls are provided which extend from an area externally of the boundary walls and which penetrate a boundary wall and terminate within the furnace section. The latter boundary wall is provided with a seal assembly extending over the area of penetration of the boundary wall. Fluid is passed sequentially through the tubes forming the boundary walls and the division walls to heat the fluid and convert it to vapor.