Database Preparation

The docking calculations are usually iterated separately for each molecule of a database. Since the calculation times per molecule are still quite large even for fast algorithms (about a minute per ligand), the use of a workstation cluster or parallel hardware is of great advantage. Within FlexX, a task 

Commonly, there are components that are not in any database of failure rates, or the data do not apply for the environment or test and maintenance at your plant. In addition, site specific data may be needed for regulatory purposes or for making the plant run safer and better. For both cases there is a need for calculating failure rate data from incident data, and the mechanics of database preparation and processing. 

Practical probability is the limit of two ratios (Section 2.2). The numerator is the number of cases of failure of the type of interest (N) the denominator, the nonnalizing term is the time duration over which the failures occurred or the total number of challenges to the system. The former has the units of per time and may be larger than 1, hence it cannot be probability which must be less than 1. The latter is a dimensionless number that must be less than 1 and can be treated as probability. 

The numerator is a random normally distributed variable whose precision may be estimated as V(N) the percent of its error is f (N)/N = f (N). For example, if a certain type of component has had 100 failures, there is a 10% error in the estimated failure rate if there is no uncertainty in the denominator. Estimating the error bounds by this method has two weaknesses 1) the approximate mathematics, and the case of no failures, for which the estimated probability is zero which is absurd. A better way is to use the chi-squared estimator (equation 2,5.3.1) for failure per time or the F-number estimator (equation 2.5.3.2) for failure per demand. (See Lambda Chapter 12 ), 

The mode of failure in a test is examined carefully before the failure is included in the database. In the diesel-generator example, unsatisfactory performance may have been reported because of a trip on a low oil pressure signal, high oil temperature, or both. 

Because these trips are disabled by a loss nf cooling signal, they should be disregarded in calculating the diesel reliability in a loss of cooling sequence. If liic trip were bypassed the diesel would have failed, and it is counted as a failure. 

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A summary of levels of 1,4-dichlorobenzene detected in indoor air is shown in Table 5-3. An update of the 1980 national ambient VOCs database prepared for the EPA summarized concentrations of... 

Database preparation is an important aspect of virtual screening. Molecules must be represented by one or more chemically sensible states and must be formatted appropriately for the virtual screening tool to be used. Relevant considerations include storage format(s), 2D-3D conversion or 3D structure generation, stereochemistry, charge, tautomers, protonation, and conformers. The impact of different database preparation protocols has not been thoroughly evaluated. Limited information in this area indicates that database preparation does impact final screening... 

When preparing conformational ligand databases, we are interested in maximally leveraging the time required for database preparation and the space required for data storage. Since the data can typically be used for multiple target systems, each with different small-molecule requirements, it is most efficient to tag the compounds with a variety of information. This allows the incorporation of physicochemical properties as well as target- or therapeutic area-specific information (see later sections of this chapter), all of which can be used to select subsets of the compounds for specific purposes. 

Knox, A.J., Meegan, M.J., Carta, G., and Lloyd, D.G. (2005) Considerations in compound database preparation hidden impact on virtual screening... 

Bologa, C.G., Olah, M.M., and Oprea, T.I. (2006) Chemical database preparation for compormd acquisition or virtual screening. Methods in Molecular Biology, 316, 375-388. 

Solvent activities of polymer solutions have been measured for about 60 years now. However, the database for polymer solutions is still modest, in comparison with the enormous amount of data available for mixtures of low-molecular substances. Three explicit databases have been published in the literature up to now. The database prepared by Wen Hao et al. is summarized in two parts of the DECHEMA Chemistry Data Series. Danner and Higtf provided a database and some calculation methods on a floppy disk with their book. WoUfarth prepared the most complete data collection regarding vapor-liquid equilibrium data of polymer solutions. His annually updated electronic database is not commercially available however, personal requests can be made via his e-mail address given above. 

For example, using the database prepared by the Chemistry Department at the University of Akron http //ull.chemistry.uakron. edu/erd/) which is considered to an academic work, the flash point of perchloroethylene is reported as 113°F. In addition the Royal Society of Chemistry s data portal Chemspider (http /AA/ww. chemspider.com/Chemical-Structure.29106.html) reports a value of 83.4°F. However, various internet sources, such as Wikipedia http //en.wikipedia.org/wiki/Fetrachloroethylene), the Center for Disease Control s Pocket Guide to Chemical Hazards (http //www. cdc.gov/niosh/npg/npgd0599.html), and most MSDSs report that the flash point value is "NA" which is presumed to mean "none."... 

Registration to databases preparing for biological testing e.g. weighing,... 

Information on the occurrence and levels of various flavonoids in fruits, vegetables, beverages and foods can be found in online databases prepared by the US Department of Agriculture, Agricultural Research Service (2002,2003,2004). 

Information on the occurrence and levels of various flavonoids in fruits, vegetables, beverages and foods can be found in on-line databases prepared by the US Department of Agriculture, Agricultural Research Service (2002, 2003,2004). Other reports relate to the flavonol (Hertog etal. 1992,1993) and flavan-3-ol (Arts etal. 2000a,b) content of Dutch produce and the flavan-3-ol content of Spanish foodstuffs and beverages (de Pascual-Teresa etal. 2000). Gu etal. (2003) have produced a report on the proanthocyanidin content of 88 different foods obtained in the United States. 

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