Chemical basis of selectivity

Wilson, N.S., Dolan, J.W, Snyder, L.R., Carr, P.W., and Sander, L.C., Colnmn selectivity in reversed-phase liqnid chromatography iii. The physico-chemical basis of selectivity, J. Chromatogr. A, 961, 217, 2002. 

The selective response to glucose in this PCSA plot indicates that the PLS calibration model is selective for glucose and unaffected by the spectral features of sucrose and maltose. In terms of the spectra, this selectivity implies that the quantitative measurements are based on the NAS for glucose relative to sucrose and maltose. In this way, the calibration model is orthogonal to the spectral features of both sucrose and maltose. Indeed, Figure 13.8 shows the PLS calibration vector superimposed on the calculated NAS for glucose relative to sucrose and maltose. These vectors overlap, which indicates that the PLS calibration vector corresponds to the NAS, thereby defining the chemical basis of selectivity for this case. 

N. S. Wilson, J. W. Dolan, L. R. Snyder, P. W. Carr, L. C. Sander, Column selectivity in reversed-phase liquid chromatography III. The physico-chemical basis of selectivity, /. Chromatogr. A 961 (2002), 217-236. 

With the foregoing developments and with additional results to be discussed in this section, it is possible to demonstrate a qualitative understanding of the chemical basis of ion selectivity. As further studies complete the determination of the elemental rate constants, as further studes adequately determine temperature dependencies, and... 

Albert, A. (1985) Selective Toxicity The Physico-Chemical Basis of Therapy, 7th edn, Chapman and Hall, London. 

Albert, A. 1973. Structure-activity relations. In Selective Toxicity the Physico-Chemical Basis of Therapy. London Chapman and HaU chapter 7. 

The concept of the PCSA method is general and this method should be applicable to many types of multivariate calibration techniques. As near-infrared and other spectroscopic methods are developed further for noninvasive in vivo clinical measurements, it is critical to understand the chemical basis of measurement selectivity. Unfortunately, calibration models generated from multivariate statistics are typically accepted without further investigation. Application of the PCSA method can help to establish the chemical or spectroscopic basis of predicted concentrations. 

In this article, we offer a brief and select overview of the literature on the atomic and electronic structure of the watersplitting enzyme,the chemical basis of its catalysis, and insights learned from functional model complexes. Citations cover the main review articles that are available rather than primary works. 

Having laid down the physico-chemical basis of interface and colloid science in Volume I, we can now make a start with the systematic treatment. Solid-gas and, in particular, solid-liquid interfaces are selected as the first topics. The argument for this choice is that such Interfaces do not change their area upon adsorption and/or charging, and are therefore the simplest group of model systems. In Volume III, dealing with fluid-fluid Interfaces, this restriction will be relaxed. 

Williams (150) has addressed this question in his 1981 Royal Society Bakerian Lecture on Natural Selection of the Chemical Elements. This describes how the biological selection of elements and their chemical properties are related. Williams has also given a detailed account (51) of the chemical basis of the uptake of elements by biological systems, and described (130) the chemistry that may occur in the specific case of aluminum. Based on this analysis he suggests a major problem with acid rain is the increased biological availability of aluminum. 

Detectors may be classified on the basis of selectivity. A universal detector responds to all compounds in the mobile phase except carrier gas. A selective detector responds only to a related group of substances, and a specific detector responds to a single chemical compound. Most common GC detectors fall into the selective designation. Examples include flame ionization detector (FID), ECD, flame photometric detector (FPD), and thermoionic ionization detector. The common GC detector that has a truly universal response is the thermal conductivity detector (TCD). Mass spectrometer is another commercial detector with either universal or quasi-universal response capabilities. 

A. Albert, Selective Toxicity, the Physico-chemical Basis of Therapy ,... 

The contributors to this book were hand selected because of their expertise in their respective fields. Individually each chapter presents a unique perspective into the clinical, developmental, neurochemical, and/or physical chemical basis of autism. The contributing authors summarize current research findings in their respective areas and also present novel ideas and propose hypotheses and possible mechanisms that may be operative during development and the potential consequences of having defects in specific molecules, receptors, or genes. 

This is an mportant theme in behavioral and holistic healthcare. The first sets a rather different background, concerning the essentially material, chemical basis of our emotions. Although we have not investigated it in this book, it is plausible that various Zen and existential states we described are associated, at least in the subjective feel of it, with brain hormones such as neuropeptides. The works listed below relate to such a broad selection of themes. 

Nayar, j. K. and G. Fraenkel, The chemical basis of the host selection in the Mexican bean beetle, Epilachna varivestis (Col-eoptera, Coccinellidae), Annu Ent. Soc. Am. 56, 174-178 (1963). 

The adaptive value of deterrent receptor cells in preventing toxication by allelochemics in non-host plants seem to be evident. Other examples which, in terms of our present knowledge, are more difficult to explain on the basis of selective value, are deterrent cells sensitive to allelochemics that do not occur in the insects normal habitat (Schoonhoven, 1981). Possible explanations could be (i) a redundancy from earlier phylogeny and, (ii) a still unknown chemical similarity of the used stimulating deterrent with compounds present in the insect s natural environment. 

In our early marketing experience with HYTREL, we first positioned it as a competitive replacement for medium to high performance specialty rubbers. Then, as now, rubber products were positioned on the basis of selected properties to fit particular applications. As a result, HYTREL was defin primarily as a rubber, albeit one with thermoplastic processing characteristics, and it was marketed on the basis of its elastomeric properties and heat and chemical resistance. 

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