The solvation parameter model is now well established as a useful tool for obtaining quantitative structure-property relationships for chemical, biomedical and environmental processes. The model correlates a free-energy related property of a system to six free-energy derived descriptors describing molecular properties. In this book the use of gas chromatography, reversed-phase liquid chromatography, micellar electrokinetic chromatography, and two-phase partitioning for determining solute descriptors is described. A large database of experimental retention factors and partition coefficients is constructed after first applying selection tools to remove unreliable experimental values and an optimized collection of varied compounds with descriptor values suitable for calibrating chromatographic systems is presented.
Sorption is considered the most important abiotic process for determining the fate and transport of organic contaminants in the environment. Sorption of organic pollutants by natural sorbents (soils, sediments, clays, humic materials, and dissolved organic matters), factors affecting sorption and sorption coefficients for selected pollutants are reviewed on the basis of the literature results and interpretations, with varieties of references examined. The most significant aspects of the sorption process are discussed: sorption isotherms and sorption kinetics, effects of sorbent physico-chemical characteristics (Water Solubility, Polar/Ionic Character, Octanol/Water Partition Coefficient, Acid/Base Chemistry Oxidation/Reduction Chemistry etc.),effect of the temperature, sorption of volatile compounds, effect of the sorbent concentration, The experimental and prediction methods adopted for the determination and estimation of the sorption coefficients are also described. Literature sorption coefficients for selected hydrophobic, polar, and ionizable compounds are collected.
Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online.In organic chemistry and the pharmaceutical sciences, a partition (P) or distribution coefficient(D) is the ratio of concentrations of a compound in the two phases of a mixture of two immiscible solvents at equilibrium. Hence these coefficients are a measure of differential solubility of the compound between these two solvents. Normally one of the solvents chosen is water while the second is hydrophobic such as octanol. Hence both the partition and distribution coefficient are measures of how hydrophilic or hydrophobic a chemical substance is. Partition coefficients are useful for example in estimating distribution of drugs within the body. Hydrophobic drugs with high partition coefficients are preferentially distributed to hydrophobic compartments such as lipid bilayers of cells while hydrophilic drugs preferentially are found in hydrophilic compartments such as blood serum.
Classical methods which can be used to reduce the blurring, noise or both at the same time, such as filtering and iterative methods are discussed. In this era, the need for the faster algorithm is importunate. While all classical iterative methods need iteration numbers between 50 to 100 or more wherever blur and noise increase in the images. In the proposed algorithms, a discrete wavelet transform is used to divide the image into two parts. This partition will help in increasing the manipulation speed of images that are of big sizes. The first part represents the approximation coefficients, the blur is reduced by using the modified fixed-phase iterative algorithm recovery of blurred images. The second part represents the detail coefficients, the noise is removed by using the wavelet thresholding techniques. Many of such techniques are used like, VisuShrink, SureShrink and BayesShrink, in soft and hard thresholding. BayesShrink represents the best method because it can be used for different types of noise with excellent restored images.
This book relates the physicochemical properties of phenolic compounds to their antioxidant activities. It focuses on the partitioning of phenolic compounds between hydrophilic and lipophilic environments and the relevance this has to their in vivo health effects. The partition coefficients (log P) of phenolic antioxidants were measured by RP-HPLC. The lipid Peroxidation Inhibition Capacity Assay (LPIC), based on using liposomes to simulate a cell membrane environment, was developed to measure the activity of antioxidants with a broad range of structures. The activities were correlated against several physicochemical parameters and used to derive a predictive model to calculate the LPIC activity. The LPIC activities also correlated well to published LDL inhibition activities but not to measured ORAC activities. These findings suggested that behaviours of antioxidants in the small unilamellar vesicles of the LPIC assay were similar to that in the LDL assay but not to the aqueous phase based ORAC assay. The LPIC assay may therefore be a better indicator of potential health benefits of antioxidants in the human body.
Syntheses of thirty-one aroylacrylic acids, twenty-seven 2-[(carboxymethyl)sulfanyl]-4-oxo-4-arylbutanoic acids (CSAB), three 2-[(2-carboxyethyl)sulfanyl]-4-oxo-4-arylbutanoic acids, one 2-[(1-carboxyethylsulfanyl]-4-oxo-4-arylbutanoic acid, one 2-[(2-methoxy-2-oxoethyl)sulfanyl]-4-oxo-4-arylbutanoic acid and one 2-ethoxycarbonylmethylsulfanyl]-4-oxo-4-arylbutanoic acid, are described. Conformational preferences of CSAB in polar and non-polar solvents, DMSO and chloroform, are examined. Analysis of conformational preferences in solution (NAMFIS analysis) is performed, using 1H NMR, NOESY, J-HMBC spectra, and conformational assemblies of compound obtained by CS in Macro Model and OMEGA. Most abound conformers in non-polar chloroform have an extended shape - largest part of apolar surface area of molecules are exposed to solvent. Advantages of methods based on 3D structure of compounds for the estimation of n-octanol/water partition coefficients (logP values) are briefly outlined. In 'extended' conformations divalent S atom could form non-covalent intermolecular interactions with other heteroatoms (O, N) in closest proximity.
This book presents an overview of recent advances in our understanding of the genesis of diamonds and the associated phases. It is divided into three main parts, starting with an introduction to the analysis of diamond inclusions to infer the formation processes. In turn, the second part of the book presents high-pressure experimental studies in mantle diamond-parental mineral systems with representative multicomponent boundary compositions. The experimental syngenesis phase diagrams provided reveal the physicochemical mechanisms of diamond nucleation and substantiate the mantle-carbonatite concept of the genesis of diamonds and associated phases. Lastly, the book describes the genetic classification of diamond-hosted mineral inclusions and experimentally determined RE "mineral-parental melt" partition coefficients. The physicochemical experimental evidence presented shows the driving forces behind the fractional evolution of the mantle magmas and diamond-parental melts.Given the depth and breadth of its coverage, the book offers researchers essential new insights into the ways diamonds and associated minerals and rocks are naturally created.