A water-soluble selenoxide (DHS(ox)) having a five-membered ring structure enables rapid and selective conversion of cysteinyl SH groups in a polypeptide chain into SS bonds in a wide pH and temperature range. It was previously demonstrated that the second-order rate constants for the SS formation with DHS(ox) would be proportional to the number of the free SH groups present in the substrate if...

effects of temperature and percentage of organic modifier were studied on retention and selectivity in rp-hplc using solvation parameter model. the system constants were determined by multiple linear regression analysis from experimental values in the retention factor for a group of different solutes with known descriptors by computer using the program spss/pc. the experimental results showed t...

In this theoretical research, the mechanism of the C2H + C2H2 reaction is studied by high-level quantum-chemical methods and kinetics of the reaction is investigated by statistical rate theories. High-level electronic structure calculation methods including M06-2X, CCSD(T), CBS-Q and G4 methods are employed to explore the doublet potential energy surface of the reaction and compute the molecula...

The focus of this work is on quantifying the degree of the aqueous-phase formation of α-hydroxyhydroperoxides (α-HHPs) via reversible nucleophilic addition of H2O2 to aldehydes. Formation of this class of highly oxygenated organic hydroperoxides represents a poorly characterized aqueous-phase processing pathway that may lead to enhanced SOA formation and aerosol toxicity. Specifically, the equi...

The formation constants of the species formed in the systems H+ + thallium(I) + AMP and H+ + AMP have been determined in aqueous solutions of methanol at 25 degrees C and constant ionic strength 0.1 mol dm(-3) sodium perchlorate, using spectrophotometric and potentiometric techniques. Thallium(I) forms two mononuclear 1:1 complexes with AMP of the type TlHL and TlL- in the pH range of study (1-...

the charge-transfer complexation reaction between iodine and dibenzo- 18-crown- 6 (db18c6) has been studied spectrophotometrically in chloroform solution at different temperatures. the resulting donor-acceptor complex was formulated as (db 18c6…i )i . the spectrophotometric results , as well as the conductivity measurements, indicated that the gradual release of tiiodide ion from its contact io...

Bivalent copper and the Schiff's base pyridylalpydidylhydrazine form two compounds, composed respectively of one molecule and of two molecules of the organic compound to one atom of copper, and having ultra violet absorption spectra differing only in the value of the molar extinction coefficients at the absorption maxima, 15,100 and 22,450, respectively at 345 mμ. The respective formation const...

We have studied the velocity dispersion of guided waves in transversely isotropic formations. Theoretical velocity dispersion curves were calculated with elastic constants based on laboratory and field measurements and compared to dispersion curves for isotropic formations having the same vertical po and S-wave velocities. The symmetry axis for the transverse isotropy was parallel to the boreho...