Proximity searching

A number of methods have been developed to introduce context to on-line databases, enabling searches to be refined to minimized false retrieval. One of the earliest techniques is proximity searching, in which two words are required to be adjacent, or within a limited distance from each other in text. The assignment of roles to chemical substances is a method of precoordinating concepts. A substance can be identified as a reactant, as a product, and in some systems in a number of additional roles. For example, by searching for documents in which formaldehyde is a product, documents in which it is a reactant, or in which it undergoes no reaction, are thus eliminated. 

This means there are 42 entries that have the words AMBIDENT and NUCLEOPHILE somewhere in them in the titles, keywords, or index entries. We can now, if we wish, display any or all of them. But a particular entry might have these two words in unrelated contexts, e.g., it might be a paper about ambident electrophiles, but which also has NUCLEOPHILE as an index term. We would presumably get fewer papers, but with a higher percentage of relevent ones, if we could ask for AMBIDENT NUCLEOPHILE, and in fact, the system does allow this. If we type S AMBIDENT(W)NUCLEOPHILE, we will get only those papers in which the term NUCLEOPHILE directly follows AMBIDENT, with no words in between.41 This is called proximity searching, and there are other, similar commands. For example, the use of (4A) instead of (W) will give all instances in which the two words appear 4 or fewer words apart, in either order. 

The abstract text for each document averages about 150 words and is more indicative than informative of document content. However, when convenient, results and data are included. Words in the abstract and title are part of the Basic Index and are searchable using free text searching techniques. Because each sentence in the abstract is a unit, proximity searching can be used for more specific retrieval during free text searching. 

One of the things missing in the list of search terms is the relationship of the search terms to each other in the complete chemical substance name. It is possible in a search term system to retain information about the original order of search terms as they appear in context. Thus, the fact that methyl is preceded by 3 can be retained and used at search time to obtain those chemical substances with 3 followed by methyl (i.e., 3-methyl) as part of the systematic name. Such search methods are known as adjacency or proximity search methods and they require that the search terms requested be in the order specified and as close as indicated with or without intervening search terms. 

After return to the Commander window, the reaction retrieval may be executed separately 629 Dicls-Aldcr reactions between aliphatic dienes and cyclic dicno-pliiles are found. This partial result can be narrowed down by restricting tlie reaction conditions by means of the fact editor, The search field codes for the yield and the temperature can be found to be RX.NYD and RX.T, respectively, either by browsing the database structure or by applying the Find option, as described in the first example. To ensure that the retrieved reaction conditions belong to the same experiment, both search terms must be connected by means of the PROXIMITY operator. Before the retrieval is started, the option "Refine results in... 

Provides access to textual and numeric data in its databases for information retrieval and reporting needs. Features word proximity and phrase searching thesaurus and index. 

The CES family of proteins is characterized by the ability to hydrolyze a wide variety of aromatic and aliphatic substrates containing ester, thioester, and amide bonds (Heymann 1980, 1982). Cauxin is a member of the CES family, and is secreted from the proximal straight tubular cells into the urine in a species-, sex-, and age-dependent manner. Therefore, we postulated that cauxin was involved in an enzymatic reaction in cat urine and the products made by the reaction should vary with species, sex, and age. Based on this hypothesis, we searched for physiological substrates and products of cauxin in cat urine and identified 2-amino-7-hydroxy-5,5-dimethyl-4-thiaheptanoic acid, also known as felinine. 

Bombs shatter and scatter the scene debris will contain fragments of the explosive device, any container in which it was held, and also the remains of items which were in immediate proximity. The size of such fragments wiU depend on the explosive performance and device size, as will the degree of fragment scatter and the chance of recovery of evidentially significant items. A preHminary search should be made to identify and recover any obvious evidential items. Arrangements should then be made to recover the bomb scene debris for more detailed searching. 

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