Derwent abstract

Although there are overlaps one should not speak of duplicates, but of mutual supplementary information. Derwent s patent abstracts are more application orientated, while Chemical Abstracts is fact-orientated. Derwent abstracts contain a paragraph Use/Advantage. 

The World Patent Index of Derwent Information Ltd. is a broad collection of international value-added patent documents from 40 patent-issuing authorities. The bibliographic database contains 11.6 million patent records with 5.5 million images (October, 2002) and grows by 1.5 million patent documents each year. The classified and indexed documents (since 1963) are sometimes provided wdth additional abstracts or significant titles. 

World Patents Index DIALOG, ORBIT, Questel, STN Derwent Information Ltd. international limited bibliographic data patent families comprehensive English language abstracts of basic and some equivalent granted patents polymer and chemical stmcture indexing for subscribers drawings... 

USPatents ORBIT Derwent, Inc. U.S. full bibliographic data abstract and full cl aim text... 

World Patents Index / APIPAT ORBIT Derwent Information Ltd. American Petroleum Institute international limited bibhographic data patent families comprehensive English language abstracts of basic patents aU Wodd Patents Index and APIPAT indexing for subscribers... 

With the advent of on-line searching in the 1970s, the Derwent file was one of the first to go on-line. It had subject retrieval capabiUty by the manual and punch code systems, tide terms, IPC, and broad subject groupings called Derwent classes, whose primary function had been to allocate patents to appropriate segments of the Derwent system. By 1981, abstracts were added to the database, after which abstracts for the entire back-file were added. 

In its eadiest years, the printed ChemicalP hstracts provided lengthy abstracts that could often serve as surrogates for original documents. Derwent stiU does this in some instances, but CAS on the other hand strives to be a pointer to original documents. The volume of nonpatent and patent Hterature covered in CA dictates that complete abstracts are impractical, although CA indexing records can contain a wealth of detail not hinted at in abstracts. 

The Chinese patent file with its abstracts can be used to supplement WPI, which at this writing has only tides for Chinese patents. JAPIO provides abstracts based ia particular oa pateat claims, and can help to clarify uncertainties with Japanese abstracts from Derwent and/or CA. PATOLIS, ia Japanese, is a unique source of Japanese legal status information (37). EPIDOS staff carry out PATOLIS searches on request for those with sufficient need to search the PATOLIS database, software is available to enable those who cannot read Japanese to extract key data. 

Other Databases with Patent Information. The APIPAT database has been discussed, as have the unique capabihties of the merged WPI—APIPAT file on ORBIT. Many other databases contain substantial amounts of patent information, notable among them are Derwent s biotechnology Abstracts the TULSA database (petroleum exploration and production), several specialized pharmaceutical files, PAPERCHEM, and METADEX. A very complete listing of databases containing patent information circa 1990 has been prepared (38). 

The stability of perchlorofluoroalkanes is due to the absence of hydrogen atoms that may be abstracted by reaction with hydroxyl radicals. Attention has therefore been directed to chlorofluo-roalkanes containing at least one hydrogen atom (Hayman and Derwent 1997). Considerable effort has also been directed to the reactions of chloroalkanes and chloroalkenes, and this deserves a rather more detailed examination in the light of interest in the products that are formed. 

The reason that the ODPs of these CFC replacements are much smaller than those of the original CFCs is the presence of an abstractable hydrogen with which OH can react. However, this also means that they can also contribute to ozone formation in the troposphere. Hayman and Derwent (1997) have used their photochemical trajectory model to calculate tropospheric ozone-forming potentials of some of these CFC replacements. Table 13.10 summarizes these relative ozone-forming potentials, expressed taking that for ethene as 100. Clearly, although they react in the troposphere, their contribution to tropospheric ozone formation is expected to be very small. 

World Patents Index. WPI, produced by Derwent Publications, Ltd., contains records of patent publications from 32 issuing authorities around the world. Since 1970, all chemical technologies are included. Prior to then, content varies as follows polymers from 1966, agricultural chemicals from 1965, and pharmaceuticals from 1963. Records contain bibliographic data and an abstract, which describes the novel features of the patent. The patent tides and abstracts in WPI are created by Derwent and generally give a more definitive description of the patent s content than the title and abstract, which appear on the document itself Records also list equivalent or family member patents that have been identified as covering the same or related invention(s) (92). 

There are a number of commercial sources of chemical information that are very detailed and encompassing, but generally available only at high cost to industrial users. These include the Chemical Abstracts Service (www.cas.org), Dialog (library.dialog.com/bluesheets/html/ bl0304.html), Prous Science (www.prous.com), and Derwent (www.derwent.com) databases. In... 

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