Abstract basis class

Although the implementation of the methods so fer may seem obvious, efficiency has not yet been mentioned. The distribution of elements and atom states of ambiguous molecules could be calculated easily using a list of all the admissible sequences of elements and atom states (E(i), Z(i)). However, this would turn out to be highly inefficient as soon as ( ) = emd Z(i) = Zg need to be represented. This problem was solved by introducing em abstract basis class atom type with the function... 

Like atom type, the substructure restriction is implemented as an abstract basis class. At present, the following types of such restrictions are available ... 

As a class of compounds, the two main toxicity concerns for nitriles are acute lethality and osteolathyrsm. A comprehensive review of the toxicity of nitriles, including detailed discussion of biochemical mechanisms of toxicity and stmcture-activity relationships, is available (12). Nitriles vary broadly in their abiUty to cause acute lethaUty and subde differences in stmcture can greatly affect toxic potency. The biochemical basis of their acute toxicity is related to their metaboHsm in the body. Following exposure and absorption, nitriles are metabolized by cytochrome p450 enzymes in the Hver. The metaboHsm involves initial hydrogen abstraction resulting in the formation of a carbon radical, followed by hydroxylation of the carbon radical. MetaboHsm at the carbon atom adjacent (alpha) to the cyano group would yield a cyanohydrin metaboHte, which decomposes readily in the body to produce cyanide. Hydroxylation at other carbon positions in the nitrile does not result in cyanide release. 

Compounds of the form RN2 X are named by adding the suffix -diazonium to the name of the parent compound RH, the whole being followed by the name of X- (Rule C-931.1, e.g., methanediazonium tetrafluoroborate, benzenediazonium chloride, not phenyldiazonium). Following RC- 82.2.2.3 (IUPAC, 1993), diazonium ions may also be named structurally on the basis of the parent cation diazenylium HNJ, e.g., benzenediazenylium ion. We name the substituent — NJ diazonio (not diazonium) following the same rule. Diazonio describes both mesomeric structures — N = N and — N = N. If one wants to describe one of these structures only, diazyn-l-ium-l-yl or diazen-2-ylium-l-yl has to be used for -N = N or -N = N, respectively. In the General Subject Index of Chemical Abstracts and in Beilstein, diazonium compounds as a class are indexed under this heading. 

Note Whether the member variable compoundList of CompoundLibrary should be declared as an interface—List or a concrete type—ArrayList should be determined on a case-by-case basis. If the concrete class has methods that are not defined in the interface or the abstract class, you are better off defining the variable as the concrete type. Otherwise, you need to explicitly cast the variable to the concrete type every time you use those methods. Either way, the clients of CompoundList are no longer affected by the decision made by the developer of CompoundLibrary with regard to the data type of compoundList variable, which is what abstraction or encapsulation is all about. 

Abstract. In this contribution, a comprehensive document model is presented, which describes the types and dependencies of documents as well as their internal structures and dynamic behavior. Additionally, the contents of documents can be indicated by integrating the document model with a product data model. Due to these properties, the document model provides an adequate basis for a novel class of software tools that support efficient document handling in development processes. 

ABSTRACT Quinones constitute a structurally diverse class of phenolic compounds with a w ide range of pharmacologial properties, which are the basis for different applications in the broad field of pharmacy and medicine. In traditional medicine all over the world, plants which are rich in quinones are used for the treatment of a variety of diseases. Besides the classical applications of these plants in industry (dyestuffs) and pharmaceutical (laxatives) practice, the relatively new field of biologically active quinones will be discussed. This review gives an account of the work done on naturally occurring bioactive quinones from 1992 to the present date. The biological activity detected in quinones from natural and synthetic sources has been discussed in relation to chemical structure under the respective titles. 

Abstract Recent advances achieved in the numerical resolution of the Time-Dependent Schrodinger Equation (TDSE), have made possible to address difficult problems in the analysis of highly nonlinear processes taking place when an atom is submitted to an ultra-intense laser pulse. We discuss the main properties of the photoelectron spectra obtained when a high frequency harmonic field is also present in addition to the laser field. This class of processes is believed to serve as a basis to explore new secnarios to achieve a coherent control of atomic photoionization. 

To make the search for analogies efficient, AIMB abstracts from the crystal library classes of substructural components. The classes of substructural pieces are then organised hierarchically. The broadest classification scheme places components into one of three classes ring assemblies, rings, and chains. The components of each class are then differentiated on the basis of size. The components are further differentiated on the basis of such things as atom and bond type. 

Three different approaches have been used for computer-assisted interpretations of chemical data. 1. Heuristic methods try to formulate computer programs working in a similar way as a chemist would solve the problem. 2. Retrieval methods have been successfully used for library search (an unknown spectrum is compared with a spectral library). 3. Pattern recognition methods are especially useful for the classification of objects (substances, materials) into discrete classes on the basis of measured features. A set of characteristic features (e.g. a spectrum) of an object is considered as an abstract pattern that contains information about a not directly measurable property (e.g. molecular structure or biological activity) of the object. Pure pattern recognition methods try to find relationships between the pattern and the "obscure property" without using chemical knowledge or chemical prejudices. 

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