Prunes spectra

The DENDRAL project initiated in 1964 at Stanford was the prototypical application of artificial intelligence techniques - or what was understood at that time under this name - to chemical problems. Chemical structure generators were developed and information from mass spectra was used to prune the chemical graphs in order to derive the chemical structure associated with a certain mass spectrum. 

Plum (prunes) Sugar content 2 FID spectrum with surface coil 76 00... 

Further details such as stopping criteria for growing decision trees, strategies for pruning decision trees and for constructing classification trees are described in [36]. An example of a classification tree to detect the presence of bromine in a mass spectrum is shown on pages 205-215. We will consider similar problems in Chapter 8, using an implementation by B. D. Ripley ([251], Chapter 7) via an interface to the statistics... 

Dithianone is a broad-spectrum fungicide. Calnan reported dermatitis in a female horticulturalist working in a fruit orchard who became sensitive to dithianone [141]. Contact occurred from the sprayed trees while pruning and also from cleaning the spraying machines. Patch testing was positive with 1% dithianone in petrolatum. 

Spectrum interpretation is a two-track procedure (INTERPRET, Figure 9). On one track, the molecular formula and the collective spectral properties of the unknown are processed by PRUNE to give rise to the ACF shortlist, a subset of the exhaustive set of the uniformly sized, explicitly defined basic units of structure. PRUNE is modular in nature and tests each ACF in the exhaustive list for compatibility with the molecular formula and the observed spectral data. 2D NMR data, if entered, are also used in pruning. PRUNE also includes a self-consistency routine to eliminate structural contradictions among the ACFs of the shortlist. Since PRUNE is biased to retain an invalid ACF rather than risk deleting a valid ACF, it is common for an ACF shortlist to contain more invalid than valid fragments (see Section 4.3). The ACF shortlist can, but need not, be edited by the user. 

The molecular formula and collective spectral data are passed to the two-track spectrum interpretation module (INTERPRET). PRUNE (see Section 6.3) produces the ACF shortlist. The second track, INFER (see Section 6.3), yields a series of constraints from two separate interpreters INFER2D (see Section 3.5) and INFERCNMR (see Section 3.2). 

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