Quantum chemical calculations reveal that neither steric hindrance nor less polar solvent medium is able to reduce the otherwise high hydrolysis rate of arsenate-esters. These results question the stability of As-DNA not only in aqueous but also in non-aqueous environments.

The biosorption of hexavalent chromium from aqueous solutions by Opuntia cladodes and ectodermis from cactus fruits was investigated. Both types of biomass are considered low-cost, natural, and ecofriendly biosorbents. Batch experiments were carried out to determine Cr(VI) biosorption capacity and the efficiency of the biosorption process under different pH, initial Cr(VI) concentration, and so...

Oligoglycines designed in a star-like fashion, so-called tri- and tetraantennary molecules, were found to form highly ordered supramers in aqueous medium. The formation of these supramers occurred either spontaneously or due to the assistance of a mica surface. The driving force of the supramer formation is hydrogen bonding, the polypeptide chain conformation is related to the folding of helica...

Newkome-type first, second and third generation dendrimers, having t-butyl (GB), ethyl (GE) and carboxylic (GA) end groups, were synthesized. A pyrene group, which can act as fluorescent sensor, was attached to the core of the dendrimers and their photophysical properties in aqueous solution were studied. These dendrimers were found to aggregate in aqueous solution, which manifested as an excim...

The dediazoniation of p-hydroxybenzenediazonium ion (PDQ) in a neutral aqueous medium has been studied under controlled experimental conditions to prevent photochemical and/or heterolytic side-reactions. Oxygen increased the dediazoniation rate of PDQ and caused the appearance of quinone and hydroquinone. An accumulation of quinone deriving from the reduction of PDQ by hydroquinone was also obs...

Kinetics of ruthenium (III) catalysed oxidation of essential amino acid, arginine by hexacyanoferrate (III) has been carried out in aqueous alkaline medium at 35°C.The rate of the reaction shows first order dependence on hexacyanoferrate (III). The reaction rate is first order at low concentrations of amino acid and alkali both and tends towards zero order at higher concentrations of substrate ...

The photoreactivity of chlorothalonil was studied by means of steady-state irradiation and laser-flash photolysis. Experiments were conducted in water containing acetonitrile as a co-solvent. This fungicide undergoes very slow phototransformation in the first stages of the reaction, but the consumption profile is auto-accelerated. To understand the reaction mechanism, we undertook a detailed st...

Light-absorption spectra of complexes between reduced iron-protoporphyrin IX (2 X 10-S M) and various polylysine samples (up to 2 X 1OW residue molar) were measured in the range 380-630 rnp in deaerated aqueous solutions of pH 12 and at 27”. The absorption spectra obtained were very similar to well-known ferrohemochrome spectra of proteins or of complexes of protoheme with low-molecular-weight ...

Borohydride salts have been considered as good prospects for transportable hydrogen storage materials, with molecular hydrogen released via hydrolysis. We examine details of the hydration of sodium borohydride by the combination of X-ray absorption spectroscopy and first principles' theory. Compared to solid sodium borohydride, the aqueous sample exhibits an uncharacteristically narrow absorpti...

Drug release from therapeutic biomedical films such as drug-polymer composite coatings on drug eluting stents is a highly complex and poorly understood process. The dynamics of drug release and the evolution of surface morphology during release have direct impact on the performance of the device. This information is not easily accessible, and there have been few systematic studies to investigat...