Data homolog

Fig. X-9. Zisman plots of the contact angles of various homologous series on Teflon O, RX , alkylbenzenes (f), n-alkanes , dialkyl ethers , siloxanes A, miscellaneous polar liquids. (Data from Ref. 78.)...

A major contribution to the rational organization of contact angle data was made by Zisman and co-workers. They observed that cos 6 (advancing angle) is usually a monotonic function of 7l for a homologous series of liquids. The proposed function was... 

At present, the data base used for the fit was not specially selected to avoid homologous proteins. Thus, a further improvement can be expected from using data for one of the specially prepared lists of PDB files (cf. Hobohm et al. [9]). We also expect further improvements from replacing the polynomial fits in the potential estimation procedure by piecewise cubic fits though at the moment it is not clear how to select the number of nodes needed to get a good but not overfitting approximation to the density. Finally, we are considering... 

Calculation can also explain why in some thiazole dyes vinyiene shift of the first two homologs is larger than the shift between higher members of the series, and also why wavelengths of absorption of nonsymmetrical dyes as calculated by the mean value rule differ from experimental data (6671. This deviation is caused by an interannular no-bond SS-interaction in the monomethine ion. 

There are many simple two-parameter equations for Hquid mixture constituents, including the Wilson (25), Margules (2,3,18), van Laar (3,26), nonrandom two-Hquid (NRTI.v) (27), and universal quasichemical (UNIQUAC) (28) equations. In the case of the NRTL model, one of the three adjustable parameters has been found to be relatively constant within some homologous series, so NRTL is essentially a two-parameter equation. The third parameter is usually treated as a constant which is set according to the type of chemical system (27). A third parameter for Wilson s equation has also been suggested for use with partially miscible systems (29,30,31). These equations all require experimental data to fit the adjustable constants. Simple equations of this type have the additional attraction of being useful for hand calculations. 

WC Barker, MO Dayhoff. Evolution of homologous physiological mechanisms based on protein sequence data. Comp Biochem Physiol [B] 62 1-5, 1979. 

An effective method for localizing causes of redox potentials is to plot the total backbone and side chain contributions to ( ) per residue for homologous proteins as functions of the residue number using a consensus sequence, with insertions treated by summing the contribution of the entire insertion as one residue. The results for homologous proteins should be examined for differences in the contributions to ( ) per residue that correlate with observed redox potential differences. These differences can then be correlated with any other sequence-redox potential data for proteins that lack crystal or NMR structures. In addition, any sequences of homologous proteins that lack both redox potentials and structures should be examined, because residues important in defining the redox potential are likely to have semi-sequence conservation of a few key amino acid types. 

Development of the Nomograph. Tw o main sources of data were used to develop the nomograph McAuliffe and Price. The hydrocarbons were divided into 14 homologous series as listed in Table 1. Solubilities at 25°C were then regressed with the carbon numbers of the hydrocarbons in order to obtain the best fit for each homologous series. A second order polynomial equation fits the data very well ... 

In fact, this procedure can be used for any aliphatic series such as alcohols, amines, etc. Consequently, before dealing with a specific homologous series, the validity of using the methylene group as the reference group needs to be established. The source of retention data that will be used to demonstrate this procedure is that published by Martire and his group [5-10] at Georgetown University and are included in the thesis of many of his students. The stationary phases used were all n-alkanes and there was extensive data available from the stationary phase n-octadecane. The specific data included the specific retention volumes of the different solutes at 0°C (V r(To)) thus, (V r(T)) was calculated for any temperature (Ti) as follows. 

The IR spectra of isoxazole derivatives have been extensively investigated. " The most exhaustive and precise data, including both the characteristic frequencies and intensities, were reported by Katritzky and Boulton " for isoxazole and its homologs, aryl- and alkoxy-isoxazoles, acids, and some other derivatives. 

Some members of the Liliaceae accumulate free azetidine-2-carboxylic acid in a much higher concentration than that found to be lethal to mung bean seedlings, but it is not incorporated into their proteins. Fowden (43) postulated that these plants either had a proline-incorporating system which was more specific than that found in other species, or some subcellular mechanism operated to prevent the homolog from reaching the sites involved in protein synthesis. Data which supported the first suggestion were subsequently obtained (116). 

For a more detailed description or modeling of the surfactant properties of the alkanesulfonates it is necessary to use individual, well-defined compounds typical of the technical mixtures. Recently, new data were obtained from a series of individual homologous alkanesulfonates in which the positions of the functional group and the cations vary [38]. 

Because secondary alkanesulfonates are used as mixtures of homologs and sulfo group isomers, ecological and toxicological data are presented for these technical products. If not otherwise indicated, the data reported are based on information of two of the major producers [101,102]. 

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