Quasiparticle dynamics in ferromagnetic compounds of the Co-Fe and Ni-Fe systems

We report a theoretical study of the quasiparticle lifetime and the quasiparticle mean free path caused by inelastic electron-electron scattering in ferromagnetic compounds of the Co-Fe and Ni-Fe systems. The study is based on spin-polarized calculations, which are performed within the $GW$ approximation for equiatomic and Co- and Ni-rich compounds, as well as for their constituents. We mainly focus on the spin asymmetry of the quasiparticle properties, which leads to the spin-filtering effect experimentally observed in spin-dependent transport of hot electrons and holes in the systems under study. By comparing with available experimental data on the attenuation length, we estimate the contribution of the inelastic mean free path to the latter.Comment: 10 pages, 10 figure

Computational drug repositioning for chagas disease using protein-ligand interaction profiling.

Chagas disease, caused byTrypanosoma cruzi(T. cruzi), affects nearly eight million people worldwide. There are currently only limited treatment options, which cause several side effects and have drug resistance. Thus, there is a great need for a novel, improved Chagas treatment. Bifunctional enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS) has emerged as a promising pharmacological target. Moreover, some human dihydrofolate reductase (HsDHFR) inhibitors such as trimetrexate also inhibitT. cruziDHFR-TS (TcDHFR-TS). These compounds serve as a starting point and a reference in a screening campaign to search for newTcDHFR-TS inhibitors. In this paper, a novel virtual screening approach was developed that combines classical docking with protein-ligand interaction profiling to identify drug repositioning opportunities againstT. cruziinfection. In this approach, some food and drug administration (FDA)-approved drugs that were predicted to bind with high affinity toTcDHFR-TS and whose predicted molecular interactions are conserved among known inhibitors were selected. Overall, ten putativeTcDHFR-TS inhibitors were identified. These exhibited a similar interaction profile and a higher computed binding affinity, compared to trimetrexate. Nilotinib, glipizide, glyburide and gliquidone were tested onT. cruziepimastigotes and showed growth inhibitory activity in the micromolar range. Therefore, these compounds could lead to the development of new treatment options for Chagas disease

Discovery of novel Schistosoma mansoni PDE4A inhibitors as potential agents against schistosomiasis

Aim: Due to the urgent need for effective drugs to treat schistosomiasis that act through a known molecular mechanism of action, we focused on a target-based approach with the aim to discover inhibitors of a cyclic nucleotide phosphodiesterase from Schistosoma mansoni (SmPDE4A). Materials & methods: To discover new inhibitors of SmPDE4A homology models of the enzyme structure were constructed based on known human and protozoan homologs. The best two models were selected for subsequent virtual screening of our in-house chemical library. Results & conclusion: A total of 25 library compounds were selected for experimental confirmation as SmPDE4A inhibitors and after dose-response experiments, three top hits were identified. The results presented validate the virtual screening approach to identify new inhibitors for clinically relevant phosphodiesterases