First-Principles Semiclassical Initial Value Representation Molecular Dynamics

A method for carrying out semiclassical initial value representation calculations using first-principles molecular dynamics (FP-SC-IVR) is presented. This method can extract the full vibrational power spectrum of carbon dioxide from a single trajectory providing numerical results that agree with experiment even for Fermi resonant states. The computational demands of the method are comparable to those of classical single-trajectory calculations, while describing uniquely quantum features such as the zero-point energy and Fermi resonances. By propagating the nuclear degrees of freedom using first-principles Born-Oppenheimer molecular dynamics, the stability of the method presented is improved considerably when compared to dynamics carried out using fitted potential energy surfaces and numerical derivatives.Comment: 5 pages, 2 figures, made stylistic and clarity change

Promising New Inhibitors of Tyrosyl-DNA Phosphodiesterase I (Tdp 1) Combining 4-Arylcoumarin and Monoterpenoid Moieties as Components of Complex Antitumor Therapy

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is an important DNA repair enzyme in humans, and a current and promising inhibition target for the development of new chemosensitizing agents due to its ability to remove DNA damage caused by topoisomerase 1 (Top1) poisons such as topotecan and irinotecan. Herein, we report our work on the synthesis and characterization of new Tdp1 inhibitors that combine the arylcoumarin (neoflavonoid) and monoterpenoid moieties. Our results showed that they are potent Tdp1 inhibitors with IC50 values in the submicromolar range. In vivo experiments with mice revealed that compound 3ba (IC50 0.62 µM) induced a significant increase in the antitumor effect of topotecan on the Krebs-2 ascites tumor model. Our results further strengthen the argument that Tdp1 is a druggable target with the potential to be developed into a clinically-potent adjunct therapy in conjunction with Top1 poisons

Sacrificial Oxidants as a Means to Study the Catalytic Activity of Water Oxidation Catalysts

An overview of the different sacrificial oxidants used in literature is reported, paying particular attention to the “sacrificial pair”, a photosystem made of a Ru-dye (Tris(bipyridine)ruthenium(II) dichloride, working as “antenna” for visible light) and a final electron acceptor (i.e. the persulfate ion). Such sacrificial oxidant is one of the most common in the literature and it was used in all the experiments described in Chap. 4. Different configurations of batch reactors can be used in the sacrificial-oxidant-driven water oxidation (WO) reaction, and three of them (i.e. the Clark-electrode Cell, the Stripping Flow Reactor and the Bubbling Reactor) are described in detail. The effects of both mass transfer limitations and side reactions on the determination of the two parameters describing the activity of water oxidation catalysts (i.e. the O2 production rate and the total evolved O2) are discussed, evidencing how such undesired phenomena occur to a different extent with the three reactor configurations