Georgeff's controlled production systems 65 8.3.3

List of Tables Table 4-1: Status determined based on the ''alues returned by selection rules 13 ACKNOWLEDGMENTS 1 would like to thank

This paper presents an "expert system" devised to aid organic chemists in determining the structure (i.e. the arrangement of atoms and bonds) of newly isolated, naturally occurring compounds. The system exploits a data base of rules for analyzing.013 C nuclear magnetic resonance spectra" [2. 13 C spectroscopy is a relatively new technique; only in the last ten years, at most, has this analytic approach been practical. Currently, no general interpretive schemes exist for thoroughly analyzing 13C spectra. A few limited classes of compounds have been investigated in detail, and highly specific schemes for interpreting their 13C spectra have been developed. The only generally applicabl- "interpretation rules" rely on correlation J of spectral and substructural features.

For This paper and the following one' describe the current effort most applications the familiar geometric point group is chosen to provide the CONG EN (for constrained structure generation) .22 In some spectroscopic applications It is necessary to take program with stereochemical capabilities.* This paper is primarily internal motion into account and specify a nonrigid symmetry concerned with the chemical and mathematical theory group.2b For applications in dynamic stereochemistry it is necessary to this effort. The following paper is concerned primarily necessary to consider the group of all permutations of identical with novel algorithms and the computer implementation.7 atoms and often several subgroups.3 Symmetry groups that A third paper considers the theory in greater mathematical include the point group and operations that invert chiral centers detail with some extensions to other topics.' are useful both in constructing chirality functions4 and in specifying the pseudochirality of a structure.5

Report 77-11 Structure Elucidation Based on Computer S Stanford -- KSL Analysis of High and Low Resolution Mass Spectral Data. A tremendous effort has been directed toward development of advanced instrumentation for mass spectrometrlc analysis. Advancements include everincreasing sensitivities and resolving powers, new ionization techniques, metastable ion probes of ion decomposition and structure and computer systems for rapid acquisition and reduction of data. We sometimes lose sight of the fact that these developments are designed to provide information about chemical and biochemic,a1 structures at greater TeTTE--aTrin greater detail than previously available. The ultimate goal in most research in mass spectrometry is to provide powerful tools for molecular structure elucidation, either directly, by exploitation of existing techniques, or indirectly by development of new techniques. Concurrently, several computer-based techniques designed to assist chemists in the analysis and interpretation of mass spectral data have been developed. Reprinted with permission from Smith, Dennis H. and Carhart, Raymond E. in "High Performance Mass Spectrometry: Chemical Applications," Michael Gross, Ed., in ACS SYMPOSIUM SERIES, No. 70; American Chemical Society: Washington, D.C., 1978, pp.325-347. Library search procedures (2) and their extensions (I) or attern recoviitioz programs (4) may provide clues to t e identity of the structure or be used to determine the structure uniquely. A computer program for analysis of spectra based on classspecific fragmentation rules, is available (5). There are several reasons or this lag: There is no formal theory.

A Glossary of Terms Used in Protein Crystallography.. - - - - A KNOWLEDGE-BASED SYSTEM FOR THE INTERPRETATION OF PROTEIN X-RAY CRYSTALLOGRAPHIC DATA ABSTRACT The broad goal of this project is to develop intelligent computational systems to infer the three-dimensional structures of proteins from x-ray crystallographic data. The computational systems under development use both formal and judgmental knowledge from experts to select appropriate procedures and to constrain the space of plausible protein structures. The hypothesis generating and testing procedures operate upon a variety of representations of the data, and work with several different descriptions of the structure being inferred. The system consists of a number of independent but cooperating knowledge sources which propose, augment and verify a sol.uticn to the problem as it is incrementally generated.

The use of computers in chemistry and biochemistry has been widespread for many years, with machines performing many complex numerical calculations, e.g.

Cells function as organized chemical engines carrying out a large number of transformations, called bioreactions or biochemical reactions, in a coordinated manner. These reactions are catalyzed by enzymes and exhibit great specificity and rates much higher than the rates of non-enzymatic reactions. Enzymes are neither transformed nor consumed, but that facilitate the underlying reactions by their presence. The coordination of the extensive network of biochemical reactions is achieved through regulation of the concentrations and the specific activities of enzymes. Single enzymecatalyzed steps in succession form long chains, called biochemical pathways, achieving the overall transformation of substrates to far removed products.

He also taught the biochemistry course that I finally took, two years after finishing my Ph.D. David J. States deserves much of the credit as well. In the three years we have been working together, he greatly extended my understanding of not only what biologists know, but how they think. He has read several drafts of this chapter and made helpful suggestions. David Landsman, Mark Boguski, Kalí Tal and Jill Shirmer have also read the chapter and made suggestions. Angel Lee graciously supplied the gel used in Figure 4. Of course, all remaining mistakes are my responsibility.

The editors have provided him with special introductory sections as a ing guide to a thorough understand of the reports.