Interface originated modification of electron-vibration coupling in resonant photoelectron spectroscopy

We present a comprehensive study of the photon energy ($h \nu$) dependent line-shape evolution of molecular orbital signals of large $\pi$-conjugated molecules by resonant photoelectron spectroscopy (RPES). A comparison to RPES data of small molecules suggests that the excitation into different vibrational levels on the intermediate state potential energy surface of the electronic excitation is responsible for the observed effect. In this simplified picture of electron-vibration couping the character of the potential energy surfaces involved in the RPES process determines the line-shape of the molecular orbital signal for a particular $h \nu$. We use the sensitivity of this effect to probe the influence of different interfaces on the electron-vibration coupling in the investigated systems. The magnitude of the variation in line-shape throughout the particular $h \nu$ region allows to reveal significant differences within the physisorptive regime

Strategies of international fiscal competition for foreign direct investment in a model with impure public inputs

This paper concentrates on international fiscal competition for internationally mobile direct investment. We differentiate between multinational enterprises whose direct investments are internationally mobile and domestic enterprises whose investment activities are limited to their country of residence. In a model with impure public inputs we analyse strategies of tax competition and examine the effects of competition by government expenditures for public inputs under the assumption that preferences for public inputs are different for each type of firms

Will Eastern European migrants happily enter the German pension system after the EU eastern enlargement?

A major concern in Western Europe and especially in Germany is that with the EU eastern enlargement inflows of workers occur, which will be net beneficiaries of the domestic social security systems. We introduce a model and present evidence by comparing pension systems in the main source and target countries (Poland, Hungary, Czech Republic; Germany) that show that immigrants most likely have to face a burden from entering the German pension system. Only if the total number of immigrants is sufficiently large the burden may change into a gain. We conclude that if migration takes place, it will do so despite not because of the existence of the pension systems

Phencyclidine derivatives — a new class of designer drugs : studies on the metabolism and toxicological analysis

In the presented studies, the phencyclidine-derived designer drugs PCEPA, PCMPA, PCEEA, PCMEA, and PCPr were investigated regarding their metabolism and their toxicological analysis in urine. Furthermore, CYP isoform dependence of the main metabolic step and characterization of their kinetic profile were elucidated. The phencyclidine derived compounds were mainly metabolized by O-dealkylation, followed by oxidation to the corresponding acid, hydroxylation of the cyclohexyl ring in different positions, hydroxylation of the phenyl ring, N-dealkylation, and combinations of these steps. Phase II reactions consisted of partial glucuronidation and/or sulfation of some phase I metabolites. In the case of PCEPA, PCMPA, PCEEA, and PCMEA, the target analytes for the toxicological analysis were the derivatized O-dealkyl metabolites and their hydroxy isomers. In case of PCPr they were the mono-hydroxy metabolites, dihydroxy isomers and N-dealkylated mono-hydroxylated isomers. The main metabolic step of PCEPA, PCMPA, PCEEA, and PCMEA was catalyzed by different CYP isoforms. In case of the O-dealkylation of PCMEA in humans simultaneous intake of potent CYP2B6 inhibitory drugs, might lead to a decreased clearance of PCMEA.In dieser Dissertation wurden der Metabolismus und die Nachweisbarkeit der neuen Designerdrogen des Phencyclidin-Typs PCEPA, PCMPA, PCEEA, PCMEA und PCPr im Urin untersucht. Ferner wurden die die Hauptmetabolismusschritte katalysierenden Cytochrom P450 (CYP) Isoenzyme und ihr kinetisches Profil aufgeklärt. Die PCPs wurden hauptsächlich durch O-Dealkylierung gefolgt von Oxidation zur Carbonsäure, Hydroxylierung des Cyclohexylringes in unterschiedlichen Positionen, Hydroxylierung des Phenylringes, N-Dealkylierung und Kombinationen aus diesen Schritten metabolisiert. Als Phase-II-Reaktionen wurden partielle Glucuronidierung oder Sulfatierung einiger Phase-I-Metaboliten gefunden. Die derivatisierten Metaboliten der Drogen aus den Hauptstoffwechselwegen (O-Dealkylierung, O-Dealkylierung und Hydroxylierung bei; PCEPA, PCMPA, PCEEA, PCMEA; Monohydroxylierung, Dihydroxylierung, N-Dealkylierung und Monohydroxylierung bei PCPr) waren die Zielsubstanzen im toxikologischen Nachweisverfahren. Die metabolischen Hauptschritte von PCEPA, PCMPA, PCEEA, und PCMEA wurde von unterschiedlichen CYPs katalysiert. Im Falle der O-Dealkylierung des PCMEA im Menschen könnte eine gleichzeitige Einnahme von Substanzen, die CYP2B6 hemmen, zu einer verminderten Clearance von PCMEA führen

From amino acid mixtures to peptides in liquid sulphur dioxide on early Earth

The formation of peptide bonds is one of the most important biochemical reaction steps. Without the development of structurally and catalytically active polymers, there would be no life on our planet. However, the formation of large, complex oligomer systems is prevented by the high thermodynamic barrier of peptide condensation in aqueous solution. Liquid sulphur dioxide proves to be a superior alternative for copper-catalyzed peptide condensations. Compared to water, amino acids are activated in sulphur dioxide, leading to the incorporation of all 20 proteinogenic amino acids into proteins. Strikingly, even extremely low initial reactant concentrations of only 50 mM are sufficient for extensive peptide formation, yielding up to 2.9% of dialanine in 7 days. The reactions carried out at room temperature and the successful use of the Hadean mineral covellite (CuS) as a catalyst, suggest a volcanic environment for the formation of the peptide world on early Earth