Path-based fingerprints

The (logical AND) operator and the (logical NOT) operator are used along with a nonstandard SQL function nbits set. This function and other related similarity functions are contained in the Appendix. The suitability of fragment keys, path-based or circular fingerprints, for any particular purpose is the subject of ongoing research.6... 

Daylight fingerprints still did quite well, despite being used as the filter for not similar, that is, there is considerable signal in path-based methods even in the penumbra of their signal. 

A practitioner should be aware of the different expected values of a Tanimoto. Path-based fingerprints, because of their popularization by Daylight, have come to define a range of values likely to mean physical similarity, yet this range is quite different for other measures. 

Another family of fingerprints available are the MOE pharmacophore fingerprints accessible through software from the Chemical Computing group [51]. In this system, the atoms are generalized into a smaller vocabulary of pharmacophore features, after which the fingerprint is constructed based on connected paths. 

Unity 2D fingerprints [42] are also based on paths and additionally denote the presence of specific functional groups, rings or atoms. Fingerprints have been used in a number of diversity studies, for example [13, 15,39, 43-46]. 

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