Abstract: The invention provides a compound of formula (0): or a pharmaceutically acceptable salt, N-oxide or tautomer thereof; wherein: n is 1 or 2; X is CH or N; Y is selected from CH and C—F; Z is selected from C—Rz and N; R1 is selected from: -(Alk1)t-Cyc1; wherein t is 0 or 1; Optionally substituted C1-6 acyclic hydrocarbon groups R2 is selected from hydrogen; halogen; and C1-3 hydrocarbon groups optionally substituted with one or more fluorine atoms; R3 is hydrogen or a group L1-R7; R4 is selected from hydrogen; methoxy; and optionally substituted C1-3 alkyl; and R4a is selected from hydrogen and a C1-3 alkyl group; wherein Rz, Alk1, Cyc1, L1 and R7 are defined herein; provided that the compound is other than 6-benzyl-3-{2-[(2-methylpyrimidin-4-yl)amino]pyridin-4-yl}-7,8-dihydro-1,6-naphthyridin-5(6H)-one and 3-{2-[(2-methylpyrimidin-4-yl)amino]pyridin-4-yl}-7,8-dihydro-1,6-naphthyridin-5(6H)-one and salts and tautomers thereof.

Abstract: A high efficiency gas hot water heater has a vertical cylindrical water tower and a cylindrical combustion chamber secured to the wall of the vertical water tower and extending horizontally therefrom. The combustion chamber has means at the outer end for the injection of gas and air therein, the products of combustion of gas and air produced in the combustion chamber flowing into the vertical water tower which has, at its upper end, a flue. A generally horizontal water distributor is positioned within the water tower adjacent to the top. A water jacket surrounds the combustion chamber with piping providing a water inlet into the water jacket and from the water jacket into the water distributor so that the products of combustion of the gas and air in the combustion chamber flow into the vertical water tower and upwardly therethrough as water flows downwardly therethrough.

Abstract: A self-contained single structure for NOX disposal and heat recovery, comprising a burner means (12), including means to supply NOX (oxides of nitrogen) gases (146) to be reduced, primary air (130) in less-than-stoichiometric flow rate, and gaseous fuel (128) at selected flow rate. The gases flow into a first reducing section (114), in which the fuel is burned in a reducing atmosphere, and the NOX gases are reduced. Fire tubes (124) carrying water or steam are positioned to receive heat from the burning gases. At the outlet of the reducing section precooled stack gases (135) are injected (137) into the flame so as to cool the hot products of combustion. The direction of flow of hot gases is turned to 90.degree. (164) in a second section. At the end of the second section the direction of flow is turned 90.degree.