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In the following example, recursive SMARTS notation is used to combine acid oxygen and tetrazole nitrogen in a definition of oxygen atoms that are likely to be anionic under normal physiological conditions. [$([OH][C,S,P]=O),$([nH]1nnnc1)] The SMARTS above would only match the acid hydroxyl and the tetrazole N−H.
The simplest form of a group-contribution method is the determination of a component property by summing up the group contributions : [] = +.This simple form assumes that the property (normal boiling point in the example) is strictly linearly dependent on the number of groups, and additionally no interaction between groups and molecules are assumed.
Two-component systems accomplish signal transduction through the phosphorylation of a response regulator (RR) by a histidine kinase (HK). Histidine kinases are typically homodimeric transmembrane proteins containing a histidine phosphotransfer domain and an ATP binding domain, though there are reported examples of histidine kinases in the atypical HWE and HisKA2 families that are not ...
In organic chemistry, neighbouring group participation (NGP, also known as anchimeric assistance) has been defined by the International Union of Pure and Applied Chemistry (IUPAC) as the interaction of a reaction centre with a lone pair of electrons in an atom or the electrons present in a sigma or pi bond contained within the parent molecule but not conjugated with the reaction centre.
Some Wikipedians have formed a project to provide information related to chemistry. The main efforts focus on providing articles clearly written articles that give an overview of the topic, all supported by reliable sources. The Chemistry portal is maintained at Portal:Chemistry and the project banner is {{WikiProject Chemistry}}.
Connected-component labeling (CCL), connected-component analysis (CCA), blob extraction, region labeling, blob discovery, or region extraction is an algorithmic application of graph theory, where subsets of connected components are uniquely labeled based on a given heuristic. Connected-component labeling is not to be confused with segmentation.
Coupled-cluster theory can also be used to obtain solutions for excited states using, for example, linear-response, [7] equation-of-motion, [8] state-universal multi-reference, [9] or valence-universal multi-reference coupled cluster [10] approaches. The wavefunction of the coupled-cluster theory is written as an exponential ansatz:
In chemistry, a concerted reaction is a chemical reaction in which all bond breaking and bond making occurs in a single step. Reactive intermediates or other unstable high energy intermediates are not involved. [1] [2] Concerted reaction rates tend not to depend on solvent polarity ruling out large buildup of charge in the transition state.