Structural effects relationship

T. Handa, T. Nagashima and N. Ebihara, Synergistic Action of Sb2(>3 with Bromine-Containing Flame Retardants in Polyolefins. II. Structure-Effect Relationships in Flame Retardant Systems," J. of Fire Retardant Chemistry,, 37 (1981). ... 

Computer Generation of Structure-Effect Relationships from Text Databases... 

Computer generation of structure-effect relationships, 89-98 Computer graphics, 45-82... 

Aungst, B.J. Site dependence and structure-effect relationships for alkylglycorides as transmucosal absorption promoters for insulin. Int. J. Pharm. 1994, 105, 219-225. 

We are nowhere close to knowing the potential benefits that nanoscale silicone resin networks, with their special structure-effect relationship, will be able to offer irmovative technologies of the future (nanotechnology). By virtue of their organic-inorganic hybrid nature, silicones open up new paths to special functionalities and enhanced properties of materials. 

H. Bonnemann, Organocobalt Compounds in the Synthesis of Pyridines - An Example of Structure-Effectivity Relationships in Homogenous Catalysis, Angew. Chim. Int. Eng. Edn., 1985, 248. 

Investigations of the structure/effect relationship show that the intensity of the pungency does not change when 8-methyl- ran5-6-nonenoic acid in capsaicin is replaced by nonanoic acid (9 0). However, it decreases when shorter, e.g., 8 0 (75%), 7 0 (25%), 6 0 (5%), or longer fatty acids, e.g., 10 0 (50%), 11 0 (25%), are introduced. 

Marcus, R. J., Gloye, E. E., and Florance, E. T., "Computer Search of a Free-Text Data Base as a Tool for Investigating Structure-Effect Relationships," Computers and Chemistry 1, 235-241 (1977). 

The fundamental assumption of SAR and QSAR (Structure-Activity Relationships and Quantitative Structure-Activity Relationships) is that the activity of a compound is related to its structural and/or physicochemical properties. In a classic article Corwin Hansch formulated Eq. (15) as a linear frcc-cncrgy related model for the biological activity (e.g.. toxicity) of a group of congeneric chemicals [37, in which the inverse of C, the concentration effect of the toxicant, is related to a hy-drophobidty term, FI, an electronic term, a (the Hammett substituent constant). Stcric terms can be added to this equation (typically Taft s steric parameter, E,). 

As can be seen from Table 3, only modifications at the 6/3-amino groups have been successful in producing penicillins of medical significance up to this time. Several reviews have dealt with the structure-activity relationship in this area in considerable detail B-80MI51102, B-77MI51106, B-75MI51102) and should be consulted for the actual effects of structural modification on antibacterial activity. 

The structure/property relationships in materials subjected to shock-wave deformation is physically very difficult to conduct and complex to interpret due to the dynamic nature of the shock process and the very short time of the test. Due to these imposed constraints, most real-time shock-process measurements are limited to studying the interactions of the transmitted waves arrival at the free surface. To augment these in situ wave-profile measurements, shock-recovery techniques were developed in the late 1950s to assess experimentally the residual effects of shock-wave compression on materials. The object of soft-recovery experiments is to examine the terminal structure/property relationships of a material that has been subjected to a known uniaxial shock history, then returned to an ambient pressure... 

To illustrate the effect of radial release interactions on the structure/ property relationships in shock-loaded materials, experiments were conducted on copper shock loaded using several shock-recovery designs that yielded differences in es but all having been subjected to a 10 GPa, 1 fis pulse duration, shock process [13]. Compression specimens were sectioned from these soft recovery samples to measure the reload yield behavior, and examined in the transmission electron microscope (TEM) to study the substructure evolution. The substructure and yield strength of the bulk shock-loaded copper samples were found to depend on the amount of e, in the shock-recovered sample at a constant peak pressure and pulse duration. In Fig. 6.8 the quasi-static reload yield strength of the 10 GPa shock-loaded copper is observed to increase with increasing residual sample strain. 

The polarity of covalent bonds between carbon and substituents is the basis of important structure-reactivity relationships in organic chemistry. The effects of polar bonds are generally considered to be transmitted in two ways. Successive polarization through bonds is called the inductive fect. It is expected that such an effect would diminish as the number of intervening bonds increases. 

Because these stability measurements pertain to the gas phase, it is important to consider the effects that solvation might have on the structure-stability relationships. Hydride affinity values based on solution measurements can be derived from thermodynamic cycles that relate hydrocarbon p T, bond dissociation energy and electrochemical potentials. The hydride affinity, AG, for the reaction... 

A substantial body of data, including reaction kinetics, isotope effects, and structure-reactivity relationships, has permitted a thorough understanding of the steps in aromatic nitration. As anticipated from the general mechanism for electrophilic substitution, there are three distinct steps ... 

Ultimately physical theories should be expressed in quantitative terms for testing and use, but because of the eomplexity of liquid systems this can only be accomplished by making severe approximations. For example, it is often neeessary to treat the solvent as a continuous homogeneous medium eharaeterized by bulk properties such as dielectric constant and density, whereas we know that the solvent is a molecular assemblage with short-range structure. This is the basis of the current inability of physical theories to account satisfactorily for the full scope of solvent effects on rates, although they certainly can provide valuable insights and they undoubtedly capture some of the essential features and even cause-effect relationships in solution kinetics. Section 8.3 discusses physical theories in more detail. 

Another method for studying solvent effects is the extrathermodynamic approach that we described in Chapter 7 for the study of structure-reactivity relationships. For example, we might seek a correlation between og(,kA/l ) for a reaction A carried out in a series of solvents and log(/ R/A R) for a reference or model reaction carried out in the same series of solvents. A linear plot of og(k/iJk ) against log(/ R/ linear free energy relationship (LFER). Such plots have in fact been made. As with structure-reactivity relationships, these solvent-reactivity relationships can be useful to us, but they have limitations. 

After an introductory chapter, phenomenological kinetics is treated in Chapters 2, 3, and 4. The theory of chemical kinetics, in the form most applicable to solution studies, is described in Chapter 5 and is used in subsequent chapters. The treatments of mechanistic interpretations of the transition state theory, structure-reactivity relationships, and solvent effects are more extensive than is usual in an introductory textbook. The book could serve as the basis of a one-semester course, and I hope that it also may be found useful for self-instruction. 

In 2000, Simig et al. began to conduct structure activity relationships on 25 by employing the Pictet-Gams reaction. Compound 25 had been identified as an anxiolytic agent that does not show sedative side-effects. ... 

Risperidone (11) was also included among a a 1-adrenergic receptor antagonists to study a quantitative structure-activity relationship (99BMC2437). A pharmacophore model for atypical antipsychotics, including 11, was established (00MI41). An increased plasma level of 11 and 9-hydroxyrisperidone (12) was observed in combination with paroxetine (01 MI 13). The effect of vanlafaxine on the pharmacokinetics of 11 was reported (99MI13). 

It is a hallmark of the structure activity relationships of the corticoids that the effects of structural modifications that lead to increased potency are usually additive. The fact that more than half a dozen such modifications each lead to increased potency opens ever new possibilities for combinations and permutations. Meclorisone dibutyrate (74) thus combines the known... 

The ANN was able to assimilate the cause-effect relationship of the density of the ester, its structure and temperature. The training and testing results are shown in Fig. 10-14 for individual ester series. The network with the proposed training routine converged in less than 100 iterations for all the esters. 

Colquhoun D (1998) Binding, gating, affinity and efficacy the interpretation of structure-activity relationships for agonists and of the effects of mutating receptors. BrJ Pharmacol 125 924—947... 

Compound optimization, to screen a series of therapeutic diug candidates to find the compounds that are most specific for the target protein and those that cause unintended effects, i.e. improved understanding of the molecular mode of action including structure-activity relationships for on-target versus off-target effects... 

Structure activity relationships, i.e., the total pattern of change in a biological activity as a function of chemical structure, typically derived from a comparison within a chemical series so that the biological effects of substitution at each structural position may be determined and correlated. 

Polyethylene s simplicity of structure has made it one of the most thoroughly studied polymeric materials. With an estimated demand of close to 109 billion pounds in 2000 of the homopolymer and various copolymers of polyethylene,24 it is by far the world s highest volume synthetic macromolecule. Therefore, it is still pertinent to study its structure-property relationships, thermal behavior, morphology, and effects of adding branches and functional groups to the polymer backbone. 

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