A method of constructing a check digit for nonconventional chemical codes is described. (5 references) (Author)

The boundary between two neighboring rings is called the fusion lines, which is enclosed by external segments called arcs. In the code, the separation of fusion line(s) from arcs takes place in such a way that proper matching is achieved. By this procedure, the structure of a compound is recreated. (Author)

Almost three million records covering approximately 175,000 chemical compounds and involving multiple disciplines have been recorded in the Army Antimalarial Drug Program. Maximum compartmentalization of files together with a complete method of interfacing files and a unique number system has made it possible to manage this system. (2 references)…

Among other improvements in chemical nomenclature used in the Chemical Registry System, Chemical Abstracts Service intends to standardize the fundamental principles for naming cyclic structures so that procedures for the derivation of ring names can become more amenable to computer generation and translation. (Author/NH)

A computer system, named CORA, has been devised for coding chemical structures by fragmentation elements. It has been used to encode Markush formulas in patents according to the Ring codes used in the Ringdoc and Pestdoc services and results in an easy, speedy, reliable and inexpensive method. (4 references) (Author)

The first section of this precis summarizes the general nature of the present chemical information systems of the world. The discussion is presented in four parts: (1) the primary literature, (2) secondary sources and services, (3) libraries and information centers and (4) other elements categorized as informal communications. The second section…