Enhanced Phosphatidylinositol Breakdown as a Calcium-Independent Response of Rat Parotid Fragments to Substance P

The need for environmental conservation has fostered the research, development and of environmentally acceptable processes. In this respect automotive exhaust has grown in importance ever since in the USA in 1970 Congress passed a of amendments to the Clean Air Act. In Europe the implementation of automotive catalysis started in the 1980s and still is going on. present, the technological answer to emission standards is the ‘controlled three-way’, named after its ability to reduce hydrocarbons, CO and NO emission levels. The main ingredients of most commercial automotive exhaust catalysts platinum, palladium, rhodium and ceria (Ce02)15. In a strong simplification Pt/or Pd are mainly present for the oxidation of CO and hydrocarbons6, while Rh for the reduction of NOX7~° and the low temperature oxidation of CO1’. The most function of the CeO2 is the low temperature catalysis of the water gas shift&2. The activity of the catalyst is fatally affected by the presence of small of lead oxide or phosphorous oxide in the exhaust gases13. kinetic behaviour of automotive exhaust catalysts is complex as many interrelated take place between the various components present in exhaust gases and the active materials present on the catalyst. On top of that, the dynamic response automotive exhaust catalysts has to be fast and should be able to cope with a variety conditions as the composition of exhaust gases emitted by the engine of a driving car rapidly. Three-way exhaust catalysis is strongly diffusion limited complicating a of the kinetics under actual process conditions (in-situ) even more. This makes it difficult to obtain information on in-situ exhaust catalysis. about the state of a catalyst surface under actual reaction conditions can be using Fourier transform infra-re&4 and Rama&3 spectroscopic techniques., quantitative evaluation of the recorded spectra is virtually impossible in where many distinct components are present at the catalyst surface. Labelling16 utilising 3H and ‘4C may provide information about reaction mechanisms rate limiting steps in reaction kinetics, but with these radionuclides no in-situ from the catalyst surface can be obtained.