CAS Registry File

A number of files under the generic tide CAS ONLINE are available on-line on STN International. The system software, MESSENGER, includes chemical substmcture, text, and numeric data searching facHities. Chemical stmctures and Registry Numbers are contained in the CA Registry file. The four ways to search the stmctures are EXA, EAM, SSS, and CSS. 

CA Registry File CAS Orbit (dictionary), Dialog (dictionary), Questel (dictionary and structure), STN dictionary and structure) chemical substance information and identification... 

CAS. 1988. Chemical Abstract Service. CA registry file. On-line December 6, 1988. 

Table 7.14 lists the related substances of magnesium silicate as obtained from their CAS Registry files [4j. 

Austin R, Ridley D. Information Resomces for Biotechnologists, Part 1 Sequences. ChemAust 2002 6(7) 4-12. A comparison of the coverage and completeness of biosequence data in the major databases, GenBank, GeneSeq, and the CAS Registry File. 

CAS ONLINE is Chemical Abstracts Service s computerized system that provides access to substance information from the CAS registry file. CAS ONLINE allows users to search for substances on the basis of structural units, registry number, chemical name, or molecular formula. Portions of the CAS information base are licensed by several information vendors. 

CAS. 1988. CAS Registry File. Chemical Abstract Service, Columbus, OH. August, 1988. 

In 1986 a cost study was conducted to compare the cost of searching the CAS Registry File on a parallel bank of Motorola 68020-based minicomputers versus the cost of searching the file on an IBM mainframe. The cumulative costs over a five year period were noticeably higher on the mainframe if response times comparable to the five minute search machine response times were desired. If response times were reduced from about five minutes to about one minute for the average search, then cumulative mainframe costs were more than twice as great as the minicomputer costs. 

Retrieval of Polymer Structures, it is axiomatic that to conduct an efficient search, searchers need to know the rules of the database or file being searched. Although this article is not intended to be a teaching manual on how to search polymer files or databases, some basic differences between searching the CAS Registry File and searching an MDL database by means of the ISIS program merit discussion. 

Searchers who choose to search a publicly available file such as the CAS Registry File must learn the rules imposed on them by CAS (2). The CAS Registry File is remotely searchable via the Scientific and Technical Information Network (STN) in Columbus, Ohio. Anyone with an STN accoimt and a computer equipped with the necessary hardware and software may access this file. As of September 2002, the Registry file contains names, structures, or both for over 42 million substances, of which nearly 934,000 are polymers. 

Structure-based versus Source-based Representation. There are no absolute rules that specify which types of polymers shall be represented as structure-based, which as source-based, and which by both methods. lUPAC makes no definitive statement about whether a polymer shall be represented as source-based or structure-based thus, polymers may be represented both ways, and many examples of this can be found in both lUPAC s publications (1,6-13) and the CAS Registry File. 

Polymers in these eight groups are usually assigned source-based names, but these groups do not necessarily correspond to specific CAS poljuner classes. A CAS publication (16) cites 42 specific poljuner classes an up-to-date list may be viewed by entering CAS Registry File online and executing the command expand A/PCT. 

Fig. 13. Source-based record homopolymer from hexafluorotriazatriphosphorine. Poly[nitrilo(difluorophosphoranylidyne)] [28655-96-1], the corresponding structure-based representation, is also registered in the CAS Registry file.

Searchable biosequence structures are being added to the CAS Registry File on STN International. Novel search and display techniques including annotations have been developed to permit onhne sequence searching. ... 

ADDITION OF ATOM/BOND STEREOCHEMISTRY TO THE CAS REGISTRY FILE... 

---