Chemical Databases Trends

TOXMAP is a Web resource that uses maps of the United States to show the amount and location of toxic chemicals released into the environment. Data are derived from the TRI database (described above), which provides information on toxic releases into the environment as reported by US industry. TOXMAP helps users create nationwide or local area maps showing where chemicals are released into the air, water, and ground. It also identifies the releasing facilities, color-codes release amounts for a single year, and provides multi-year chemical release trends, starting with 1987. Users can search the system by chemical name, chemical name fragment, and/or location (such as city, state, or zip code). TOXMAP also overlays map data such as US Census population data. 

Another likely trend is the availability of new chemical databases for in-house use. We are already seeing this. Examples are additional reaction libraries, chemical structure, biological response, and bibliographic databases tailored to particular areas of interest, as well as additional collections of physico- chemical property data such as log P,pKa, and spectra libraries. ... 

In addition to the computer software and hardware trends that will impact chemical-scientific database systems in the future, trends in chemistry will also impact them. The disciplines of genetic engineering and polymer chemistry have special needs for chemical database technology, as do computational chemistry and patent applications. The chemical/pharmaceutical industry will enjoy important gains in productivity when these needs are better provided for. 

Current research trends indicate that the development of new representation schemes and search algorithms will continue (a) in support of combinatorial library design and manipulation (b) targeting small molecule and macromolecular 3D structural data and (c) other novel chemical IR concepts which are unknown at present. Improved search performance is inevitable and necessary, since the size of chemical databases will continue to increase. These enhancements will be a consequence of algorithm design, improved data representation, and faster computer hardware. 

This review includes most of the published articles from the defined area and excludes only imidazoquinolines, which were reviewed in Weissberger-Taylor s series The Chemistry of Heterocyclic Compounds (81MI1). Comprehensive Heterocyclic Chemistry II (96MI1) mentioned only some of the azoloquinolines in the first edition the authors omitted citations about this type of compounds. The trend toward interest in these compounds can be illustrated by the number of citations in Chemical Abstract as shown in Table I. Besides Chemical Abstracts Substance/Subject (Collective) Indexes, the MDL database search has been used. 

Though some more traditional thermodynamicists will be dismayed by the concept of solution phase bond dissociation enthalpy, the fact is that the database involving these quantities is growing fast. When used judiciously, they may provide important chemical insights—as is indeed the case for the stability of the O-H bond in phenolic compounds. Although solution phase bond dissociation enthalpies are not true bond dissociation enthalpies, because they include some contribution from intermolecular forces, a series of solution values like those in table 5.2 may be (and often is) taken as a good approximation of the trend in the gas-phase. 

Several organisations have lately established electronic databases, recording details of industrial chemical accidents. These should enable the user to learn lfom others mistakes and also establish a fixed version of accidents, which hitherto have changed in the retelling, and the more important have often been retold. The two above are examples of a wider trend. All tend to reflect the pre-occupations of their compilers, which are generally not so much the precise chemical causes of the mishap, but its effects. 

There are limited data on the chemical resistance of various oxide materials in the literature (Samsonov 1982, Ryshkewitch and Richerson 1985). Furthermore, many of the studies are concerned with solid, nonporous materials. Nevertheless, these may provide an indication of the general trends. Until a definitive and quantitative database of chemical stability of various inorganic membranes becomes available, some simple dissolution-type test methods using membrane samples may be employed on a comparative basis to estimate the extent of attack by a chemical under the application conditions. An example of such a simple test is given below. 

Theoretical calculations can also provide physicochemical data, which can be used as an input for 3D-QSAR correlation studies [134,141]. There is a current trend in the area of lead-finding in the pharmaceutical industry to use calculations to set up computer search profiles to be used in the screening of large structural databases, such as the chemical suppliers databases and the internal company databases. 

While not convincing from a statishcal perspective, the results in this section are consistent with a trend high-activity molecules published in the past decade of medicinal chemistry literature are more likely to be found in the large, hydrophobic and poor solubility corner of chemical property space. These results are not consistent with, for example, cell-based [41] and median-based [42] partihoning of biologically active compounds however, such analyses were performed in the presence of inactive compounds selected from MDDR[41] or ACD [42], with quite probably unrelated chemotypes. ACD, the Available Chemicals Directory [43], and MDDR, the MDL Drug Data Report [43], are databases commonly used by the pharmaceuhcal industry. 

Obach, R.S., Lombardo, F. and Waters, N.J. (2008) Trend analysis of a database of intravenous pharmacokinetic parameters in humans for 670 compounds. Drug Metabolism and Disposition The Biological Fate of Chemicals, 36, 1385—1405. 

Sheridan RP, Nachbar RB, Bush BL (1994) Extending the trend vector The trend matrix and sample-based partial least squares. J Comp Aided Mol Des 8 323-340 Sprague PW (1995) Automated chemical hypothesis generation and database searching with CATALYST. Persp Drug Disc Design 3 1-20... 

For the terrestrial environment, waste sites may act as major emission sources of mixtures. In the United States, the Agency for Toxic Substances and Disease Registry (ATSDR) has performed a trend analysis to identify priority chemical mixtures associated with hazardous waste sites (De Rosa et al. 2001, 2004 Fay 2005). The information was extracted from the Hazardous Substance Release/Health Effects Database (HazDat) (ATSDR 1997). The HazDat contains data from hundreds of hazardous waste sites in the United States. A trend analysis was completed for frequently co-occurring chemicals in binary or ternary combinations found in air, water, and soil at or around hazardous waste sites (Fay and Mumtaz 1996 De Rosa et al. 2001, 2004). Table 1.1 gives an overview of frequently occurring substances at hazardous waste sites in the United States. 

So, some trends seem to be selection of a few systems (either by market consolidation or users who rely on a database they are comfortable with) that include multiple databases or a combination of bibliographic and property and chemical data and linking programs that tie primary literature with other forms of data or secondary and tertiary literature. 

The immense number of chemical compounds formed by the halogens provides chemists with an extraordinary database from which numerous chemical and physical phenomena can be correlated with respect to various periodic trends. From databases like Inorganic Crystal Structure Data (ICSD, http //www.fiz-karlsruhe.de ) and International Centre for Diffraction Data (ICDD, http //www.icdd.com) with 67 000 and 25 000 entries, respectively, one can easily make out that halides are one of the dominant classes of compounds besides oxides. Even within the subset of inorganic solids, there is tremendous diversity of composition, stracture, and properties and to summarize this would create its own encyclopedia. Therefore, the discussion in this article is limited primarily to binary halides, their structures, and some of their properties, except halides of elements which are nonmetals. Binary actinide hahdes are discnssed elsewhere see Actinides Inorganic Coordination Chemistry). Complex hahdes (sohd phases containing two or more kinds of metal ions), ... 

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