Searching Systems

Besides structure and substructure searches, Gmclin provides a special search strategy for coordiuation compouuds which is found in no other database the ligand search system, This superior search method gives access to coordination compounds from a completely different point of view it is possible to retrieve all coordination compounds with the same ligand environment, independently of the central atom or the empirical formula of the compound. 

The pre-processing concepts have been a more recent development of substructure searching systems. These approaches have become popular since the mid-1980s, when the cost of the storage devices (hard disks and CD-ROMs) decreased. 

T. L. Clerc, in Computer-Enhanced Analytical Spectroscopy, H. L. C. Meuzelaar, T.L. Isenhour (Eds.), Plenum Press, New York, 1987, pp. 145-162. Automated spectra interpretation and library search systems. 

Stmcture searching and display software are host-specific. The Softon Substmcture Search System (S4) was developed by the Beilstein Institute and Softon of Graefelfing Germany (50). It is a full stmcture and substmcture searching module. The S4 is used in-house by the Beilstein Institute and is operated by DIALOG. STN uses CAS ONLINE s messenger software for on-line stmcture searching of the Beilstein on-line database (51). 

Description, Acquisition, Retrieval, and Correlation File. This is the only other pubhc substmcture search system, apart from CAS Online, that provides full access to the CAS Chemical Registry File. The DARC file, commercially available on-line from Telesystems-Questel, offered the first pubhc on-line implementation of substmctural searching of the CAS Chemical Registry System. The advantages and disadvantages of the CAS Online and DARC systems have been discussed (49). 

Structure and Nomenclature Search System. This system links the collection of chemical databases found in the Chemical Information System (CIS), one of the first interactive systems for stmcture and substmcture searching. References from the separate files can be retrieved by SANSS using CAS Registry Numbers, and the database of stmctures may be searched for stmctures or substmctures. An adaptation of the SANSS software for substmcture searching has been incorporated in the Dmg Information System of the National Cancer Institute for its own use (54). 

The need for an overall and combined chemical structure and data search system became clear to us some time ago, and resulted in the decision to build CHIRBASE, a molecular-oriented factual database. The concept utilized in this database approach is related to the importance of molecular interactions in chiral recognition mechanisms. Solely a chemical information system permits the recognition of the molecular key fingerprints given by the new compound among thousands of fingerprints of known compounds available in a database. 

In this chapter, we will discuss the present status of CHIRBASE and describe the various ways in which two (2D) or three-dimensional (3D) chemical structure queries can be built and submitted to the searching system. In particular, the ability of this information system to locate and display neighboring compounds in which specified molecular fragments or partial structures are attached is one of the most important features because this is precisely the type of query that chemists are inclined to express and interpret the answers. Another aspect of the project has been concerned with the interdisciplinary use of CHIRBASE. We have attempted to produce a series of interactive tools that are designed to help the specialists or novices from different fields who have no particular expertise in chiral chromatography or in searching a chemical database. 

Berks AH. Cnrrent state of the art of Marknsh topological search systems. World Patent / /2001 23 5-13. 

Willett P, Winterman V, Bawden, D. Implementation of nearest neighbour searching in an online chemical structure search system. J Chem Inf Comput Sci 1986 26 36-41. 

SANSS. 1990. Structure and Nomenclature Search System. Chemical Information System (CIS)... 

ChemIDplus. Published by the U.S. National Library of Medicine, ChemIDplus [62] is a web-based search system, http //chem.sis.nlm.nih.gov/ chemidplus/, that provides free access to structure and nomenclature authority files used for the identification of chemical substances cited in National Library of Medicine (NLM) databases. ChemIDplus also provides structure searching and direct links to biomedical resources at NLM and on the Internet. The database contains over 349,000 chemical records, over 56,000 of which include chemical structures, and is searchable by name, synonym, CAS registry number, molecular formula, classification code, locator code, and structure. 

It can be seen that an energy of ca. 150 kJ/kg, comparable to that accumulated in Pb02-Pb or Ni-Cd batteries, can be obtained at voltages of 4V. Somewhat lower energy (100 kJ/kg) is accumulated at a voltage of 3V. Consequently, the searched system carbon/electrolyte should be characterised by (i) specific capacity. > 160 F per gram of activated carbon and (ii) electrochemical stability window at the level of ca. >3V. 

Reid, J.C. and Wong, E.C., Data-Reduction and -Search System for Digital Absorbance Spectra , Applied Spectrocopy 20, 320-325 (1966). 

Owens, P.M. and Isenhour, T.L., Infrared Spectral Compression Procedure for Resolution Independent Search Systems , Analytical Chemistry 55, 1548-1553 (1983). 

The literature has been covered as far as it was available to the author until the fall of 1983. In the course of the literature search certain difficulties had to be overcome. Many publications contain valuable 13C NMR information without mentioning so explicitly in the title or abstract thus, the information cannot easily be retrieved, even through Chemical Abstracts. Various reviews as well as computer search systems have been utilized as sources. Moreover, due to the enormous wealth of I3C NMR spectral data that has appeared in the last decade it is impossible to include all information available. Omission of certain papers, however, does not at all imply judgment as to their scientific value. In the beginning of this chapter (Sect. II) a brief account is presented of the basic... 

General NCBI Entrez http //www.ncbi.nlm.nih.gov/ http //www.ncbi.nlm.nih.gov/Entrez/index.html Bioinformatics databases and tools. A cross-database searching system. 

The Bulletin search system is a component of the MSSS, described above, and as such, is accessible as indicated in the previous section on the MSSS. 

C. Carbon-13 Nuclear Magnetic Resonance (CNMR) Spectral Search System. 

The data base that is used in the CNMR search system consists currently of 4,100 CNMR spectra (3). As in the case of the MSSS, every compound has a CAS registry number, and all exact duplicate spectra have been removed from the file. A specific compound may still appear in this file more than once, however, because its CNMR spectrum may have been recorded in different solvents. The CNMR file is still small but is growing at a fairly steady rate and should benefit considerably from recent international agreements to the effect that all major compilations of CNMR data will, in the future, be pooled. 

This CNMR search system has recently been made available on the ADP-Cy-phemetics network. Searches are all transaction priced at 1 — 3, and the subscription fee for the system is 100 per year. 

E. X-ray Crystal Data Search System. The National Bureau of Standards (NBS) has collected a file of data pertaining to some 24,000 crystals, including those in the Cambridge file described above (20). The data in the NBS file include the cell parameters, the number of molecules. Z. in the unit cell, the measured and calculated densities of the crystal and two determinative ratios, such as A/B and A/C. Every com-... 

F. X-ray Powder Difi action Search System. Compounds that fail to crystallize may still be examined by X-ray diffraction, because non-crystalline materials, as powders, give characteristic diffraction patterns. A collection of powder diffraction patterns proves to be a very effective means by which to identify materials and indeed, one of the very earliest search systems in chemical analysis was based upon such data by Hanawalt (21) over forty years ago. The importance of these data in TSCA can be seen by examining the TSCA Inventory regulations for treatment of confidential chemicals (22). Section 710.7 of these regulations indicates that EPA intends to rely on powder diffraction data to assure the validity and seriousness of a manufacturers request for treating information on a chemical as confidential. 

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