Computer searchable database

The advantage of generic LC/MS run conditions is that it allows the preparation of an LC/MS separation database that can be referenced for compound mixtures from anywhere in the development and manufacturing process cycle. It trades off resolution for consistency, speed, and a decrease in methods development times. It permits creation of a computer-searchable database of information for all of the compounds being investigated in the company. The mass spectrometer provides sensitivity and resolution gain as well as information on retention times and molecular weights. 

Sources and compositions of fatty materials, and characteristics of animals that will use them, were reviewed above. Approximately 3000-4000 citations on research in feeding fats to various species are available in computer-searchable databases, now approaching their twenty fifth year. The reader is referred to these for the role of fat in additional feedstuffs and animal species. Several principles stand out, which are discussed in the following paragraphs. 

The application of radiation chemistry to drug research [24,25] is conceptually simple and greatly facilitated by the ready availability of authoritative compilations of kinetic information obtained by radiation chemists [26], especially computer-searchable databases [27] and those accessible on the Internet (http //allen.rad.nd.edu/). 

It is highly recognized that the use of Fourier Transform Infrared Spectrometry (FllK) for chemical substances identification it is not a trivial task to be fulfilled by analytical chemists. The complexity of FTIR characterization comes mainly from the high degree of infrared absorption bands overlapping, that are difficult to be accurately ascribed, despite of the fact that up to date computer-searchable databases of spectra are currently available. 

Although in more casual settings, many chemists emphasize silicon s steric effect hy referring to silicon as a fat proton , attempts to find this term in the computer searchable database of organic chemistry reveal few instances of this usageT ... 

Vast tabulations of 13C chemical shift data have been assembled in computer searchable form. These databases form the basis for 13C chemical shift prediction algorithms. For the most part, carbon chemical shifts can be calculated using what is referred to as a Hierarchically Ordered Spherical Environment (HOSE) code approach [28]. To calculate a given carbon s chemical shift, the influence of each successive spherical shell is applied to the starting chemical shift for that carbon to calculate its overall chemical shift. Typically, programs will calculate shifts for 3 or 4 layers, beyond which the effects of most substituents are negligible. The spherical layers surrounding the 23-position of strychnine are shown in Fig. 10.8. 

A historical control database can take on many formats, from a simple spreadsheet (e.g., Microsoft Excel) to a fully searchable database that is interfaced or a part of the laboratory s computer data collection system. Most laboratories that conduct large numbers of studies according to GLP standards have a validated computer data collection system, and some of these systems automatically compile control data ftom studies so the user does not have to reenter the data into a separate historical control database. However, because of the inflexibility of the data acquisition systems, many laboratories still compile their historical control data by manually entering into a stand-alone database, such as customized spreadsheet format (e.g., Microsoft Excel). 

The virtual layout of the plates is generally performed on a computer with specially developed software, and subsequently executed by a robot. Therefore, it is desirable that all the reagents and protocols are registered in a searchable database. 

Table 4.3. Common computer searchable crystallographic databases.

In an actual apphcation, a small sample, 5-10 mg or more, would be taken from an artifact and crashed to a powder and mounted in the middle of the diffractometer. As the detector, as shown in Fig. 4.41, rotates around the sample, the computer counts the intensity of the X-rays at each angle and reports them in a graph as shown in Fig. 4.42. The angles at which the sample diffracts X-rays are then listed, along with their relative intensities, and compared to those in the searchable database. The computer then presents the closest matches to know minerals. In the example here, the material from an archaeological stone bowl is identified as the mineral chlinochlore. 

Every crystalline phase in a sample has a unique powder diffraction pattern determined from the unit cell dimensions and the atomic arrangement within the unit cell. It can be considered a fingerprint of the material. Thus, powder diffraction can be used for phase identification by comparing measured data with diffraction diagrams from known phases. The most efficient computer searchable crystallographic database is the PDF-4 from the International Centre for Diffraction Data (ICDD) [3]. It is used by very efficient computer-based search-processes. In 2007 the PDF-4-i- database contains information about Bragg-positions and X-ray intensities for more than 450000 compounds, out of which there are about 107 500 data sets with atomic coordinates. New entries are added every year. The positions of the peaks in the measured pattern have to be determined. This can be done manually, but effective, fast and reliable automatic peak search methods have been developed. The method can obviously be successful only if the phases in the sample are included in the database. However, the database can also help to determine unknown phases if X-ray data exist for another isostructural compound albeit with a different composition. 

PROPOSAL FOR A COMPUTER-SEARCHABLE RING CONSTRUCTION DATABASE... 

Research Portfolio Online Reporting Tools (RePORT) http //projectreporter.nih.gov/reporter. cfm (accessed June 17,2010). This resource, formally known as CRISP (Computer Retrieval of Information on Scientific Projects) is a searchable database of federally funded biomedical research projects conducted at universities, hospitals, and other research institutions. The site covers awards from 1972 to the present. 

Of course, many of these toxicity and environmental questions can be answered by the colorant vendor who will supply MSDSs (material Safety Data Sheets) and other safety and test data. In those cases where sufficient information about a particular compound is not available, it may be necessary to search one or more of the toxicity databases for analogous structures which have been examined for their toxic effects and use this information as a basis for making a judgment about the suitability of the colorant in question. These databases which are easily computer searchable include Registry of the Toxic Effects... 

Multi-step reactions as part of searchable databases can come in several forms. A reaction scheme recorded within one document (such as a total synthesis, or a multi-step procedure for performing a single transformation) is called an explicit scheme this type is the most common, and perhaps the most important. A scheme consisting of reactions assembled from different documents is called an implicit scheme, and can be located by a computer program, rather than being a record of experimental fact. Implicit schemes can be used to discover new routes to synthetic targets, and can in principle extend the utility of databases of reactions. 

The sample solution was subjected to GC-MS, which automatically records the mass spectrum of each compound as it emerges from the column. Modern instruments have a searchable database of mass spectra, which allows the best match between the case sample and known substances to be found very quickly. The results in this case are shown in Figure 3.5. Here the best match with the mass spectrum identified by the computer is with heroin. Visual examination by the human operator (still an essential part of the process ) confirms that the two spectra are virtually identical. There are small differences between the two spectra, but these are accounted for by noise in the sample spectrum (probably due to the very low concentration used) and the fact that the library spectra were probably recorded on a different instrument. The other heroin derivatives found from the database, have obvious differences in their mass spectra and can be ruled out. 

Decades of combined spectral and chemistry expertise have led to vast collections of searchable user databases containing over 300 000 UV, IR, Raman and NMR spectra, covering pure compounds, a broad range of commercial products and special libraries for applications in polymer chemistry (cf. Section 1.4.3). Spectral libraries are now on the hard disks of computers. Interpretation of spectra is frequently made only by computer-aided search for the nearest match in a digitised library. The spectroscopic literature has been used to establish computer-driven assignment programs (artificial intelligence). 

Martin, Y.C., Danaher, E.B., May, C.S., and Weininger, D. MENTHOR, a database system for the storage and retrieval of three-dimensional molecular structures and associated data searchable by sub structural, biologic, physical, or geometric properties./. Comput.-Aided Mol. Des. 1998, 1, 15-29. 

Entrez searches can be performed using one of two Internet-based interfaces. The first is a client-server implementation known as NetEntrez. This makes a direct connection to an NCBI computer. Because the client software resides on the user s machine, it is up to the user to obtain, install and maintain the software, downloading periodic updates as new features are introduced. The second implementation is over the World Wide Web and is known as WWW Entrez or WebEntrez (simply referred to as Entrez). This option makes use of available Web browsers (e.g., Netscape or Explorer) to deliver search results to the desktop. The Web allows the user to navigate by clicking on selected words in an entry. Furthermore, the Web implementation allows for the ability to link to external data sources. While the Web version is formatted as sequential pages, the Network version uses a series of windows with faster speed. The NCBI databases are, by far the most often accessed by biochemists and some of their searchable fields include plain text, author name, journal title, accession number, identity name (e.g., gene name, protein name, chemical substance name), EC number, sequence database keyword and medical subject heading. 

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