Structural keys

Fingerprints structural keys identify a molecule - code is highly compact represented in bits ambiguous not convertible to other representations dependent on the fragment library... 

Structural keys describe the chemical composition and structural motifs of molecules represented as a Boolean array. If a certain structural feature is present in a molecule or a substructure, a particular bit is set to 1 (true), otherwise to 0 (false). A bit in this array may encode a particular functional group (such as a carboxylic acid or an amidelinkage), a structural element (e.g., a substituted cyclohexane), or at least n occurrences of a particular element (e.g., a carbon atom). Alternatively, the structural key can be defined as an array of integers where the elements of this array contain the frequency of a specific feature in the molecule. 

In order to perform a database search the structural key of the query molecule or substructure is compared with the stored structural keys of the database entries. This implies that each array element in the structural key has to be defined initi-... 

Hashed fingerprints, structural keys 2D structure See Section 12.2... 

These structural key descriptors incorporate a remarkable amount of pertinent molecular arrangements covering each type of interaction involved in ligand-receptor bindings [26]. Since every structure in a database is represented by one or more of the 960 key codes available in ISIS, suppose that two molecules include respectively A and B key codes, then the Tanimoto coefficient is given by ... 

Bulky substituents at tetravalent silicon centers are the structural key element of sterically overcrowded compounds with extraordinary properties Inter- and intramolecular interactions of the bulky ligands can be studied in detail and allow an assessment of the ligands influence on structure and reactivity. 

What Carroll s team discovered is that the genes and the entire regulatory pathway that integrates them and which control anterior/posterior wing development in the Drosophila (or its common ancestor with butterflies) have been recruited and modified to develop the eyespot focus. This discovery of the facility with which new developmental functions can evolve. .. within extant structures (Keys et al., 1999, p. 534) would have been impossible without the successful why-necessary answer to the proximate question of developmental biology. 

Linear representations are by far the most frequently used descriptor type. Apart from the already mentioned structural keys and hashed fingerprints, other types of information are stored. For example, the topological distance between pharmacophoric points can be stored [179, 180], auto- and cross-correlation vectors over 2-D or 3-D information can be created [185, 186], or so-called BCUT [187] values can be extracted from an eigenvalue analysis of the molecular adjacency matrix. 

Structural keys have been used in chemoinformatics for many years, and are usually encoded by a binary array, each element of which denotes the... 

Yu, Z.B., Krstic, Z. and Krstic, V.D., (2005), Laminated silicon nitride/silicon carbide composites with self-sealed structure , Key Engineering Materials 280-283, 1873-1876. 

Pharmacophore keys are 3-D structural keys that are based on features of a molecule that are thought to have relevance for receptor binding. The features typically include hydrogen bond donors, hydrogen bond acceptors, charged centers, aromatic ring centers and hydrophobic centers. Pharmacophore keys are usually based on combinations of three or four pharmacophoric features and their associated distances. Flexibility can be taken into account by combining the keys for all distinct conformations of a molecule. 

The impact of an enhanced surface sensitivity is pictured by probing the polymer structures at different depths. In addition, the possibility of determining buried structures is addressed. Depending on the characteristic structure of the thin film a simulation of the two-dimensional GISAXS pattern is important to determine the influence of structural key parameters. Therefore GISAXS pattern simulations are shown to picture sample induced limiting factors of the detection of large scale structures. 

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