Structure-selectivity relationships 4601 Subject

In studies of quantitative structure activity relationships (QSAR), the relative potencies of a series of drugs are subjected to analysis with the hope that biological potency will be described by a mathematical equation. QSAR is an actuarial or statistical method in which only objective data are used with no intrusion of models or mechanistic hypotheses. The equation that is obtained not only accounts for the relative potencies of the compounds, but from it are deduced predictions of the potencies of untested compounds if the equation is valid, the predictions are ineluctable. The method thus has the capacity of yielding new (structurally related) drugs with desired potency, perhaps drugs with enhanced selectivity or fewer side effects. 

In addition, we have not intended that the selectivity index be the only criterion applied in the decision to subject pure compounds with significant antimalarial activity to further study. The discovery of compounds of novel structure possessing potent antimalarial activity but with relatively low (i.e., <100) SI values, such may represent lead compounds which could be synthetically modified to yield drugs with higher selectivity, and may also provide valuable insight into potential mechanisms of antimalarial action or structure-activity relationships, and thus, such compounds may also be included in mechanistic studies to a limited extent. 

The whole family of macrocyclic lactones, consisting of the closely related aver-mectins and milbemycins, displays unprecedented potency against mites, insects, and nematodes. LC90 values in greenhouse trials are often in the range 0.1-0.01 ppm, in some cases even lower. The structure-activity relationships of this chemical class have been the subject of many publications. The present section discusses selected key findings. 

This contribution aims to briefly review studies on the exploration of structure-property relationships of metal nanoparticles with a specific focus on the eflects of particle size and shape. A number of earher, more specific, and detailed reviews provide an ample opportunity for a reader to deepen understanding of this subject [8-12]. Here, the focus is to review selected recent papers, along with a limited number of historically important papers that put more recent findings into perspective. 

The selected relationships given more suggest that the analysis of precise conductance data is an invaluable tool in studies on the structure and properties of both strong and weak electrolyte solutions. This field has been the focus of attention for several decades and the reader is referred to other more complete reviews on the subject. Here, we will merely list some analytical applications in order to given an introductory insight into the use of the conductance method. 

In this book, we review several solved and unsolved problems in structure-property-activity studies, in theoretical chemistry, and in bioinformatics, which are related to the structure-property relationship in general. We have elected to discuss and elaborate on a number of problems, whether solved or unsolved, which appear to us to have not been widely or well known. Among the selected problems we have included, in particular, some problems that relate to the following four subjects ... 

When we consider the fibre properties surveyed in Section 14.2 we realize that they are, without exception, influenced by the physical structure. The role of the physical structure is not always dominant, and often it is far from being completely understood. Due to lack of space, discussion of the structure-properties relationships is limited here to three subjects, selected for their importance (1) mechanical properties, specifically Young s modulus and tensile strength (2) thermal properties, specifically the phenomena associated with the glass transition and (3) interaction with low molecular weight compounds. 

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