Soman resolution

S-200 and S-300 molecular sizing column with a fraction volume of approximately half of that used in previous studies in order to increase resolution. Three repeatable peaks capable of the hydrolysis of DFP immediately became apparent. Upon the addition of Mn2+, a fourth peak appeared. The activities were identified as Tt DFPase-1, Tt DFPase-2,... Tt DFPase-5, and their characteristics can be found in Table 10.2. Molecular weights of the Tetrahymena OPA anhydrases range from 67,000 Da to 96,000 Da. The activity of DFPase-4 is stimulated 17- to 30-fold with Mn2+. Tt DFPase-1, Tt DFPase-2, and Tt DFPase-3 are only stimulated two- to fourfold, and part of this increase may be due to contamination by the higher molecular weight Tt DFPase-4. Soman to DFP ratios are approximately 1 1 for the Tetrahymena OPA anhydrases. 

There have been descriptions of the acute toxic effects in humans that follow high-dose exposure (>LD5o) to the nerve agents soman (Lekov et al., 1966 Sidell, 1974), sarin (Sidell, 1974 Inoue, 1995 Nakajima et al., 1998), and VX (Nozaki et al., 1995). The same cluster of behavioral symptoms that are reported following lower doses (anxiety, psychomotor depression, intellectual impairment, and sleep disturbances) dominate the clinical picture in the immediate period following resolution of the acute toxic signs of intoxication and then slowly fade with time, sometimes taking months to fiiUy resolve. 

Near baseline resolution of the two diastereoisomers of soman can be obtained on nonpolar columns under normal analysis conditions and complete resolution can be obtained on more polar columns such as poly (ethylene glycol) Chiral resolution of the four iso-... 

The first evidence for enantioselectivity in the reaction of organophosphorus compounds with AChE was reported by Michel who noted a biphasic inhibition on incubation of AChE with racemic sarin. Shortly afterwards, Aaron et reported enantioselective AChE inhibitory activity for the resolved isomers of O-ethyl S-(2-ethylthioethyl) ethylphosphonothionate. Subsequent isolation, or partial resolution, of the enantiomers of sarin, soman, tabun and VX has shown that there is a very large enantioselectivity for cholinesterase inhibition k, ratios 10 -l 0 ) between the P(-) and P(+) isomers of sarin and soman, shown in Table 12. 

In the context of interest here, namely that of fault tree analysis, Lindley Singpurwalla (1986) present a formal probabilistic (Bayesian) procedure for the use of expert opinions, assuming expert input in the form of mean and standard deviation of lognormally distributed failure rates. In Tanaka et al. (1983), Liang Wang (1991) and Huang et al. (2001), basic event probabilities (chances) are treated as trapezoidal fuzzy numbers and the extension principle is applied to compute the probability (chance) of occurrence of the top event. In order to deal with repeated basic events in fault tree analysis. Soman Misra (1993) provide a simple method for fuzzy fault tree analysis based on the a-cut method, also known as resolution identity. Another approach to fuzzy fault tree analysis based on the treatment of the system state as a fuzzy variable has been proposed by Huang et al. (2004). 

Soman, K.P. Misra, K.B. (1993) Fuzzy fault tree analysis using resolution identity and extension principle. International Journal of Fuzzy Mathematics 1 193-212. 

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