Analysis of the distribution of relevant answers to 41 search profiles among the 80 subject sections of Chemical Abstracts" revealed that the average profile requires 10 CA-subject sections for adequate coverage. The average printing expense could be reduced 25 percent by searching the individual profiles in the appropriate subject sections. (5…

Chemical structure diagrams are considered as utterances in a written language. Two types of grammars are considered for this language: topological grammars and geometric grammars. The hypothesis is presented that compact computer storage may become accessible via grammars. (15 references) (Author/NH)

A collection of computer programs to do chemical information retrieval are described in terms of the interactions between the computer and the chemist. In interacting with the computer, the chemist can graphically specify two-dimensional structures as queries and view structures as search results. (18 references) (Author/NH)

The Cambridge Crystallographic Data Centre is concerned with the retrieval, evaluation, synthesis, and dissemination of structural data obtained by diffraction methods. This paper describes the use of a computer-based file system of both bibliographic information and numeric data to produce a compendium of interatomic distances. (10 references)…

A new, universally applicable computer program is described for the whole complex of punched card oriented literature documentation. Its characteristics are: modular construction, therefore easily adapted to user-specific problems; extremely high searching capacity; comprehensive and elastic syntax makes possible new unconventional methods of…

The Information Flow System is a large-scale information retrieval system developed for processing of Du Pont information files. As currently implemented, the system stores and retrieves information on company technical reports. Extensions of the system for handling chemical structure information and on-line processing are also discussed. (3…

Advantages of the Berkeley Mass Storage System (MSS) for information retrieval other than its size are: high serial-read rate, archival data storage; and random-access capability. By use of this device, the search cost in an SDI system based on the Nuclear Science Abstracts" data base was reduced by 20 percent. (6 references) (Author/NH)

In the pharmaceutical industry more emphasis will be required on tertiary sources which maintain multiple computer-based files. These files are now being made available for SDI purposes, while their usefulness for retrospective searches still needs to be evaluated. (7 references) (Author/NH)

As each Wiswesser Line Notation symbol for a structure containing a branching chain and/or multiplied groups is extracted in a left-to-right scan, the symbol to which it was connected in the graphic formula must be jnown. For highly branched structures the program logic becomes quite complex. (Author)

Construction of the locant path, a table of interatom connections, and the molformula from the WLN for complex ring systems (including polycyclic, spiro, perifused, bridged, and pseudo-bridged rings) is described. The procedure has been programmed for a digital computer and has been found useful in manual decoding also. (Author)

Describes a system for the management and analysis of chemical structure-biological activity data wherein the chemical structures, encoded in Wiswesser Line Notation, are checked for accuracy, stored, and retrieved by computer. Unification of description and activity of bio-systems. Structuring data files. (Author)

A substructure search screening system based on bond-centered fragements was evaluated using 108 queries derived from user SDI profiles. (Author/JB)