Abstract: A light fixture (50, 250, 350) is formed from a plurality of parts that are substantially snap engageable, thereby simplifying assembly and requiring few or no tools. In one embodiment, the fixture (50, 250, 350) is installable from below through a ceiling orifice and supportable by the ceiling alone, without requiring permanent attachment to an existent support beam. In another embodiment, the fixture is provided with hanger supports for attachment to ceiling hangers. The light fixture includes a reflector (70) having an ellipsoidal geometry with improved lighting efficiencies. Also provided is a firebox (500) that houses a light fixture therein.

Abstract: A down light fixture is assembled from parts that are substantially snap engageable and is installed through a ceiling orifice and supported by the ceiling without requiring permanent attachment to an existent support beam or the like. The light fixture comprises a can adapted to receive a lighting unit and installable through the ceiling orifice from its exposed side, and a decorative trim member removably and securely engageable with the can. The can is further provided with a flange on its free end that is positioned adjacent the exposed surface of the ceiling about the insertion orifice after the can has been inserted into the ceiling therethrough. The decorative trim member is rotatingly, removably and securely engageable with the flange to provide an exterior trim to the fixture. Several parts of the lighting fixture are removable and replaceable to vary the appearance of the light fixture without removal of such fixture from the ceiling.

Abstract: The invention is concerned to new hydrazones and oximes of 3-formylrifamycin SV.The procedure of rifamycin derivatives preparation consists of condensation of 3-formylrifamycin SV with reactants suitable for carbonylic group, using solvents alone or in mixture, as reaction medium, in which are attained high concentrations of reactants, and from which the reaction products can be easily isolated, by possibly a partial concentration and/or water addition, when they separate under crystalline form.The solvents and the working conditions selected, e.g. the reactant for carbonylic group in excess up to 0.25 mol, reduce the danger of inflammability, simplify the operations, decrease the degradations level and lead to pure products, so that their recrystallization is no longer necessary.Among the obtained rifamycins, may be selected products showing reduced liver toxicity, active against mycobacteria rifamycin-resistant forms or specific antiviral-oncogene, immunosuppressive, antileukemic (in man) etc.