Electrochemical evidence of catalysis of oxygen reduction at the polarized liquid–liquid interface by tetraphenylporphyrin monoacid and diacid

Cyclic voltammetry is used to study the role of 5,10,15,20-tetraphenyl-21H,23H-porphine (H2TPP) in the reduction of molecular oxygen by decamethylferrocene (DMFc) at the polarized water|1,2-dichloroethane (DCE) interface. It is shown that this rather slow reaction proceeds remarkably faster in the presence of tetraphenylporphyrin monoacid (H3TPP+) and diacid (H4TPP2+), which are formed in DCE by the successive transfer of two protons from the acidified aqueous phase. A mechanism is proposed, which includes the formation of adduct between H3TPP+ or H4TPP2+ and O2 that is followed by electron transfer from DMFc to the adduct leading to the observed production of DMFc+ and to the regeneration of H2TPP or H3TPP+, respectively

Recent advances in the use of ionic liquids for electrochemical sensing

Ionic Liquids are salts that are liquid at (or just above) room temperature. They possess several advantageous properties (e.g. high intrinsic conductivity, wide electrochemical windows, low volatility, high thermal stability and good solvating ability), which make them ideal as non-volatile electrolytes in electrochemical sensors. This mini-review article describes the recent uses of ionic liquids in electrochemical sensing applications (covering the last 3 years) in the context of voltammetric sensing at solid/liquid, liquid/liquid interfaces and carbon paste electrodes, as well as their use in gas sensing, ion-selective electrodes, and for detecting biological molecules, explosives and chemical warfare agents. A comment on the future direction and challenges in this field is also presented

Void-Assisted Ion-Paired Proton Transfer at Water-Ionic Liquid Interfaces.

At the water-trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)trifluorophosphate ([P14,6,6,6 ][FAP]) ionic liquid interface, the unusual electrochemical transfer behavior of protons (H(+) ) and deuterium ions (D(+) ) was identified. Alkali metal cations (such as Li(+) , Na(+) , K(+) ) did not undergo this transfer. H(+) /D(+) transfers were assisted by the hydrophobic counter anion of the ionic liquid, [FAP](-) , resulting in the formation of a mixed capacitive layer from the filling of the latent voids within the anisotropic ionic liquid structure. This phenomenon could impact areas such as proton-coupled electron transfers, fuel cells, and hydrogen storage where ionic liquids are used as aprotic solvents

DISTRIBUTION OF CRAYFISH IN SALZBURG, AUSTRIA

Mapping of crayfish populations in the province of Salzburg was carried out in the years 2002 and 2003. Five crayfish species were found, two of them native: Astacus astacus and Austropotamobius torrentium, and three foreign: Astacus leptodactylus, Pacifastacus leniusculus and Orconectes limosus. In former times the first two species were widely distributed especially in the northern part of the province. Today Astacus astacus is only found in (artificial) ponds and in one lake and its outlet. Austropotamobius torrentium is found in several small rivers, especially in the pre-alpine region. Astacus leptodactylus is found in three lakes connected to each other. Pacifastacus leniusculus is the most common crayfish species and widely distributed in rivers, ponds and lakes. Orconectes limosus is found in two lakes

Scheduling of Behavioral VHDL by Retiming Techniques

Abstract In this paper we present a new approach to the scheduling of behavioral VHDL descriptions for control-ow dominated applications containing a large number of nested conditionals and data dependent loops. The proposed algorithm is able to schedule and re-schedule descriptions for optimization subject to various cost functions. The timing of the I/O signals can be c ompletely xed, partially xed o r left to the scheduler. In this case the algorithm produces a schedule such that the number of clock cycles required f o r a c omplete execution of the behavioral description is minimized. Scheduling is performed a s a b ehavioral VHDL code transformation and allows taking advantage of all the power of commercial RT synthesis systems. The corresponding problem is solved b ased on an analogy to the retiming problem on RT-level networks which can be solved i n p olynomial time. The eciency of our approach is demonstrated on various examples