An information retrieval system for storing and searching Markush formulations is described. All implicit specific structures (ISSRs) of the Markush formulation are stored as a specific multiple-connectivity node representation (SpMCN) by allowing the appropriate atoms to expand beyond their normal valance and accommodate all substituents of the Markush structure. The SpMCN is simplified by using a generic group hierarchy to reduce common structural features to an associated generic multi-connectivity node representation (GnMCN) that contains within it implicit generic structures (IGSRs) corresponding to each ISSR. Attributes such as ring size and hetero atom identification are also associated with each generic feature whenever possible. The SpMCN and GnMCN are further simplified by storing their associated structural characteristics as bit strings. To search the stored Markush formulations, a query structure is reduced to its generic structure, attributes, and associated structural characteristic bits strings. The bits strings are compared with the bit strings of the stored structures to eliminate stored structures without the requisite structural features. The generic structure and attributes of the query and remaining stored structures are then compared on a group by group basis and additional structures are thereby eliminated from the search. Finally the specific structure of the query is compared with the specific structures of the remaining stored structures to determine more precisely if there is a match. Reference data, such as patent numbers, are then retrieved for the matched structures.
Comparative Molecular Field Analysis (CoMFA) is an effective computer implemented methodology of 3D-QSAR employing both interactive graphics and statistical techniques for correlating shapes of molecules with their observed biological properties. For each molecule of a series of known substrates the steric and electrostatic interaction energies with a test probe atom are calculated at spatial coordinates around the molecule. Subsequent analysis of the data table by a partial least squares (PLS) cross-validation technique yields a set of coefficients which reflect the relative contribution of the shape elements of the molecular series to differences in biological activities. Display in three dimensions in an interactive graphics environment of the spatial volumes highly associated with biological activity, and comparison with molecular structures yields an understanding of intermolecular associations. CoMFA will also predict the biological activity of new molecular species.
A molecular retrieval system and method answering to similarity queries for retrieving molecular structures, stored into a source database (22) and having a required similarity with an input structure, which can contain a set of property regions. A target database (23) stores the molecular structures described in hierarchical way and a knowledge base (24) stores well-known molecular fragments at different levels of description together with a set of physical and chemical properties associated to each fragment. A fragment recognizer (21) analyzes the fragments of the input structure to represent them in a hierarchical way. A query analyzer (25) analyzes the similarity queries and selects the appropriate level of molecular representation on the basis of the required similarity. Matching means (26, 27, 29), when called by the query analyzer (25), perform a matching of the representation of the input structure against the representations of the molecular structures stored into the target database (23) at the selected level of molecular representation.
Chemical structure data containing generic representation of component atoms in a storage device is searched by finding a match between a query structure and a stored candidate structure by mathematically comparing attribute data of chemical units of a query structure and attribute data of chemical unit of a stored candidate structure, where attribute data represent chemical characteristics of chemical units of those structures.
A case-based retrieval system and method for using same for retrieving justifiably relevant cases from a case library in which past problem solving experiences (cases) are stored. The system obtains the symptoms of a new problem. A set of cases are initially retrieved from the case library based on the symptoms of the new problem. It is then determined for each initially retrieved case using a casual explanation for the case whether the case is justifiably relevant to the new problem, with only justifiably relevant cases being returned to the user of the system.
There is disclosed a method for processing information on a two or more-step chemical reaction wherein individual reactions of producing at least one product from at least one starting material take place consecutively, information on the reactions at individual steps being given as bond information in which bonds linking two nodes are distinguished between the starting material and the product topologically superposed thereon and denoted by a pair of integers (a.sub.x.sup.i, b.sub.x.sup.i), wherein the integer a.sub.x.sup.i is bond multiplicity of the bond x of the starting material in the i-th step reaction and the integer b.sub.x.sup.i is difference in the bond multiplicity of the bond x between the product and the starting material in the i-th step reaction, which comprises performing the following operation on the basis of said bond information: wherein the integer a.sub.x.sup.jk is bond multiplicity of the bond x of the starting material in the consecutive reactions of from the j-th step to the k-th step and the integer b.sub.x.sup.jk is difference in the bond multiplicity of the bond x between the product and the starting material in the consecutive reactions, to obtain information on the consecutive reactions as bond information denote by a pair of integers (a.sub.x.sup.jk, b.sub.x.sup.jk).
