Homeostatic model assessment

X-Ray diffraction data have been used to study the aromaticity of complex quinolizinium systems, such as the acenaphtho[4,5-c]quinolizinium derivative 36. The rings connected to the molecule by single C-C bonds are more aromatic than those connected by more links as indicated by the homeostatic model assessment (HOMA) aromaticity index <1992AXC2238>. 

All the models are based upon standard statistical distributions. The Multi-Hit model is based upon a Poisson distribution. The Probit model is based upon a normal distribution, and the One Hit, Multistage and Weibull models rely upon linear probabilities. Such distributions have proven applicability in dealing with substantial percentages of the population (up to 1 in 20). However, the models lose precision when they are pushed to extremes such as 1 in 10, such as encountered in risk assessment. Furthermore, homeostatic mechanisms such as DMA repair and immunological survellance may be poorly evaluated in risk assessment. Such high doses are administered to achieve the siaximum tolerated dose, that these mechanisms are surely overwhelmed in the animal studies. Additionally it should be noted that a risk of one in a million does not mean one tumor in the lifetime of a million people, it means that each individual has one chance in a million of developing a tumor in a lifetime. 

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