Inhibitors continued efficiency

Place 25 g. of methyl methacrylate polymer (G.B. Diakon (powder). Perspex (sheet) U.S.A. Lucite, Plexiglass) in a 100 ml. Claisen flask, attach an efficient condenser e.g., of the double smface type) and distil with a small luminous flame move the flame to and fro around the sides of the flask. At about 300° the polymer softens and undergoes rapid depolymerisation to the monomer, methyl methacrylate, which distils over into the receiver. Continue the distillation until only a small black residue (3-4 g.) remains. Redistil the hquid it passes over at 100-110°, mainly at 100-102°. The yield of methyl methacrylate (monomer) is 20 g. If the monomer is to be kept for any period, add 0 -1 g. of hydro quinone to act as a stabiUser or inhibitor of polymerisation. 

Although strongly suggestive, these experiments do not prove that the normal pathway of infection involves only the endocytic route. Infection could also occur by fusion of the virus with the plasma membrane. This was shown not to be the case by allowing uptake of SFV into BHK-21 cells for 10 minutes at 37°C in the presence of inhibitory concentrations of NH4CI (Helenius et al., 1982). All of the viruses left on the cell surface were then removed by proteinase K digestion at 0°C, and after removal of the inhibitor, the incubation continued at 37°C. The intracellular viruses were shown to infect the cells almost as efficiently as in control cells. 

As technology advances, the need for improved performance from materials increases. There is also a continuing economic pressure to minimise costs, which will become increasingly difficult as resources become depleted. Thus, research is aiming at more efficient corrosion protection methods such as improved formulations for paints and corrosion inhibitors, improved metal alloys, better design, and the use of novel materials such as ceramics and plastics. 

Many of these reactions have been studied before in the section on NaOa and so will not be discussed again here. In excess NO, the rate becomes nearly first-order over most of the decomposition with a rate constant which is itself a function of the total pressure. NO2 is an inhibitor for the decomposition, and in consequence the reaction in the absence of added NO shows a steady fall in apparent first-order rate constant with continuing decomposition. In this respect the nitrates and nitrites all seem to have in common the feature that the pyrolysis products inhibit the rate of decomposition. Tliis is to be expected in systems decomposing via radical mechanisms when the products of the reaction include such efficient radical traps as NO and NO2. It is unfortunate that quantitative data on these systems are at present so sparse and in many cases disparate. This is to be expected for systems that are so complex and show such sensitivity to surface reactions. The free radical chemistry of these systems is, however, a very interesting and important one, and efforts to elucidate it will eventually turn out to be quite rewarding. 

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