Nomenclature searching search methods

Specialized search engines. There are two major projects to index specifically structure-oriented chemical information on the Web. The full-text search engines provide only textual search capabilities and index only text data. Structure-oriented search methods such as substructure search are not possible with this approach. Chemical names as search keys are problematic because the lUPAC nomenclature is far from unique, complicated, and error-prone, and many compounds are not even named by the original authors. Additionally, trivial and commercial... 

As chemical substance names are text, they are amenable to searching using a variety of text-searching methods. The methods for nomenclature searching are found in many textsearching systems. A knowledge of both the search methods and nomenclature rules permits a swift, meaningful search of chemical substance names. A search can be performed for full structure, substructures or chemical substances of unknown or variable composition. 

Complete-match methods are extremely useful in nomenclature searching. There are many ways to achieve this benefit but the basic proposition is that it is imperative to search for terms that are complete names in themselves and not derived from some larger name. For example, benzene could be a search term that is part of a larger systematic name or it could be the complete name of a chemical substance. Differentiating between these possibilities is essential. 

Systematic chemical substance nomenclature is constructed to describe a chemical structure using words, numbers, and punctuation. Text-searching methods can be applied to systematic chemical substance names to search for full structure, sub-structures, or chemical substances of unknown or variable composition. 

This activity means some loss of continuity of naming practice in indexes of all kinds. Revisions of indexes and records have been necessary to keep pace. Continuity and consistency in annual and collective indexes and in cumulative index files help the user in any literature search. But sometimes it is necessary to sacrifice continuity in order to keep up with progress in the various sciences. Nomenclature is not static. It must change with increasing knowledge of the science, with the ever-growing complexity of chemical compounds, and with the more precise methods of determining structure. 

To sequence a heparin-related compound, using property encoded nomenclature/MALDI method, the poly saccharide is first fragmented by enzymatic and/or chemical means. Mass signatures of the fragments are then obtained by MALDI-MS, and the signatures are used as constraints to search a database of possible sequences for the correct match. 

However, the introduction of online methods of retrieving informal tion, such as CAS ONLINE [9,10] and DARC [27] (which provide convenient and rapid searching of large files with the aid of graphic input and output), will reduce the future need for nomenclatures and notations by an extent that is difficult to predict. 

Most text-searching systems permit a variety of textsearching methods. This section will suggest how some of these commonly available methods can be applied to searching systematic nomenclature. 

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