Although in a recent study (1) the susceptibility of diphtheria antitoxin to the denaturing action of urea was apparently established, the question of the fundamental nature of the reaction remains essentially unsolved. Since the action of urea probably involves a partial unfolding of the polypeptide chains of proteins, the lability of antibody in urea suggests that the antibody structure resid...

Electrophilic aromatic sulfonation of benzene with sulfur trioxide is studied with ab initio molecular dynamics simulations in gas phase, and in explicit noncomplexing (CCl3F) and complexing (CH3NO2) solvent models. We investigate different possible reaction pathways, the number of SO3 molecules participating in the reaction, and the influence of the solvent. Our simulations confirm the existen...

Two C₂-symmetrical dipyrrole-polyamide dimers 2 and 3 that were tethered with triethylenetetramine and spermine, respectively, and their corresponding Cu(II) complexes 2@Cu(2+) and 3@Cu(2+), were synthesized and fully characterized. Agarose gel electrophoresis studies on pBR322 DNA cleavage indicated that both Cu(II) complexes exhibited potent DNA-cleaving activities under physiological conditi...

In this paper in situ visible electroreflectance measurements have been carried out in order to extract new electrochemical information from the dependence of R/R on the frequency of potential modulation. The behaviour of some typical components of a Au electrodeposition bath has been investigated: a metal salt (KAu(CN)2), a supporting electrolyte (NaClO4), a metal cation complexing agent (KCN)...

Trace amounts of bismuth(III) and uranium(VI) can be simultaneously determined in a single scan by adsorptive cathodic stripping voltammetry in the presence of cupferron as a complexing agent. Optimal conditions were found to be: 0.1 mol L(-1) acetate buffer (pH 5.3), 5 × 10(-5) mol L(-1) cupferron, accumulation potential of -0.25 V, and accumulation time of 30 s. The linear range of Bi(III) an...

Iodometric Back Titration (IBT) and Spectrophotometric (SPM) determination are two commonly used methods for the determination of hydrogen sulfide (H2S) concentration in sea water. These two methods were applied in parallel for analysis of Black Sea anoxic waters and artificial solutions containing different H2S concentrations. The results of the SPM and IBT methods are in agreement when the H2...