Identity activation function, defined

The single output neuron has an identity activation function defined as... 

The application of quality control procedures to ensure that satisfactory analytical performance of enzyme assays is maintained on a day-to-day basis is complicated by the tendency of enzyme preparations to undergo denaturation with loss of activity. This maltes it difficult to distinguish between poor analytical performance and denaturation as possible causes of a low result obtained for a control sample introduced into a batch of analyses. Assured stability within a defined usable time span is therefore the prime requirement for enzyme control materials, as it is for enzyme calibrators. However, specifications for the two types of materials can differ in other respects. Because the function of a calibrator is to provide a stated activity under defined assay conditions, it is not necessary for it to show sensitivity to changes in the assay system identical to those of the samples under test therefore within certain Umits, enzymes from various sources can be considered in the search for stability. However, it is the function of a control to reveal small variations in reaction conditions, so it must mimic the samples being analyzed. The preparation of enzymes from human sources is not by itself a guarantee of an effective control. For example, human placental ALP is very stable, but it differs significantly in kinetic properties from the liver and bone enzymes that contribute most of the ALP activity of human serum samples it is therefore not an ideal enzyme for use in control material for the determination of ALP. 

Parameter Oj denotes the maximum rate of recycling, divided by the Michaelis constant of the substrate for the autocatalytically regulated allosteric enzyme constant K is equal to the product concentration for which the recycling rate reaches its half-maximum value. The rate function of the product-activated allosteric enzyme is identical with that defined for eqns (2.7) with c - 0. It is given by eqn (3.2), identical with relation (2.11), which corresponds to a dimeric enzyme that binds the substrate only in the R state ... 

Certain classes of enzymes require small, auxiliary, nonprotein molecules called cofactors, coenzymes, and prosthetic groups. Definitions for these three terms are somewhat arbitrary and, in fact, the term cofactor will be used in the following chapters to represent broadly the identity and functional roles of cocatalysts. The roles of cofactors are structural, functional, or both. They provide the enzyme with the chemical or photochemical capabilities lacking in the normal amino acid side chains. An enzyme devoid of a cofactor is called an apoenzyme. Apoenzymes are catalytically inactive. The active complex of the protein and the cofactor is termed a holoenzyme. The cocatalysts can be defined on the basis of the catalytic functions that are mediated (76). 

In connection with transition-state theory, one will also occasionally meet the concept of a statistical factor [13]. This factor is defined as the number of different activated complexes that can be formed if all identical atoms in the reactants are labeled. The statistical factor is used instead of the symmetry numbers that are associated with each rotational partition function (see Appendix A.l) and, properly applied, the... 

ORNs are a large population of similar but distinct neurons. The genetic differentiation of such a group is an interesting functional and developmental problem. OR expression clearly is important but it is likely that other proteins are differentially expressed as well. A complex of signaling proteins and transcription factors determines the functional identity of the components of the olfactory network during development. The functional properties of this network during active life are then defined by the interaction of receptors, neurotransmitters... 

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