Earthquake forecasting in Italy, before and after Umbria-Marche seismic sequence 1997. A review of the earthquake occurrence modeling at different spatio-temporal-magnitude scales.

The main goal of this work is to review the scientific researches carried out before and after the Umbria-Marche sequence related to the earthquake forecasting/prediction in Italy. In particular, I focus the attention on models that aim addressing three main practical questions: was (is) Umbria-Marche a region with high probability of occurrence of a destructive earthquake? Was a precursory activity recorded before the mainshock(s)? What was our capability to model the spatio-temporal-magnitude evolution of that seismic sequence? The models are reviewed pointing out what we have learned after the Umbria-Marche earthquakes, in terms of physical understanding of earthquake occurrence process, and of improving our capability to forecast earthquakes and to track in real-time seismic sequences

Electrochemistry of Room Temperature Protic Ionic Liquids: A Critical Assessment for Use as Electrolytes in Electrochemical Applications

Ten room temperature protic ionic liquids (RTPILs) have been prepared from low-molecular-weight Brønsted acids and amines with high purity and minimal water content, and their electrochemical characteristics determined using cyclic, microelectrode, and rotating disk electrode voltammetries. Potential windows of the 10 RTPILs were established at glassy carbon, gold, and platinum electrodes, where the largest potential window is generally observed with glassy carbon electrodes. The two IUPAC recommended internal potential reference systems, ferrocene/ferrocenium and cobaltocenium/cobaltocene, were determined for the 10 RTPILs, and their merits as well as limitations are discussed. Other electrochemical properties such as mass transport and double layer capacitances were also investigated. The potential applications of these RTPILs as electrolytes for electrochemical energy devices were discussed, and two novel applications using PILs for metal deposition and water electrolysis were demonstrated

Atomic Force Microscopy Reveals the Mechanobiology of Lytic Peptide Action on Bacteria

Increasing rates of antimicrobial-resistant medically important bacteria require the development of new, effective therapeutics, of which antimicrobial peptides (AMPs) are among the promising candidates. Many AMPs are membrane-active, but their mode of action in killing bacteria or in inhibiting their growth remains elusive. This study used atomic force microscopy (AFM) to probe the mechanobiology of a model AMP (a derivative of melittin) on living <i>Klebsiella pneumoniae</i> bacterial cells. We performed <i>in situ</i> biophysical measurements to understand how the melittin peptide modulates various biophysical behaviors of individual bacteria, including the turgor pressure, cell wall elasticity, and bacterial capsule thickness and organization. Exposure of <i>K. pneumoniae</i> to the peptide had a significant effect on the turgor pressure and Young’s modulus of the cell wall. The turgor pressure increased upon peptide addition followed by a later decrease, suggesting that cell lysis occurred and pressure was lost through destruction of the cell envelope. The Young’s modulus also increased, indicating that interaction with the peptide increased the rigidity of the cell wall. The bacterial capsule did not prevent cell lysis by the peptide, and surprisingly, the capsule appeared unaffected by exposure to the peptide, as capsule thickness and inferred organization were within the control limits, determined by mechanical measurements. These data show that AFM measurements may provide valuable insights into the physical events that precede bacterial lysis by AMPs

Selenium Nanoparticles as Potential Drug-Delivery Systems for the Treatment of Parkinson’s Disease

The development of efficient drug formulations for Parkinson’s disease (PD) treatment is challenged by achieving pharmacokinetic profiles, reduced side effects, and better permeability through the blood–brain barrier (BBB). As nanoparticles may facilitate the delivery of drugs in the brain due to their high-loading capacity and ability to cross biological barriers, we designed two different types of selenium nanoparticles (SeNPs) that may increase the transport of drugs across the BBB and may act as antioxidants at the site of action. The SeNPs were functionalized with polyvinylpyrrolidone (PVP) and polysorbate 20 (Tween) and characterized in terms of their size, size distribution, shape, surface charge, and colloidal stability in relevant biological media. Their drug-loading capacity was tested using dopamine and l-DOPA as therapeutically active agents for PD. Thermodynamic analysis revealed that binding processes occurred spontaneously through hydrogen bond/van der Waals interactions or electrostatic interactions. The strongest interaction was observed between PVP-SeNPs and l-DOPA or dopamine, which was characterized by a binding constant several orders of magnitude higher than for Tween-SeNPs. However, the addition of human transferrin as a model plasma protein significantly reduced this difference, which indicates the crucial role of protein corona formation in the design of drug nanodelivery systems. In vitro evaluation by cell-free and cellular transwell models showed efficient internalization of SeNP-loaded l-DOPA/dopamine by human endothelial brain cells, while facilitated BBB permeability for l-DOPA, and dopamine was achieved using PVP-SeNPs. Overall, the high potential of SeNPs as drug-delivery vehicles in PD treatment was demonstrated

Copolyampholytes Produced from RAFT Polymerization of Protic Ionic Liquids

Polyampholytic copolymers have been synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization of protic ionic liquid monomers. The monomers were prepared by acid–base proton exchange between acid and basic precursor conjugates, each containing one or more vinyl pendant groups. The polymerization, which was carried out without additional solvents present, led to high molecular weight glassy polymers, which were stable in the form of bulk viscous liquid ionic complexes. Various polyampholytes belonging to both linear and cross-linked families were prepared by judiciously varying the molecular structure of the acid precursor. Furthermore, by using solid-state NMR, the molecular arrangement of the polymeric backbone was identified, highlighting the presence of copolymers with both random and alternating copolymer chains which in the latter case involves a regularly alternating acid monomer, whereas the base occurs as a random sequence with the average and most probable number of monomers dictated by the stoichiometry used. The structural and mechanical properties of the resulting copolyampholytes were characterized by atomic force microscopy, peak-force quantitative nanomechanical analysis, differential scanning calorimetry, and small-angle X-ray scattering. These showed that the final polymers were essentially glassy and amorphous, with weak compositional fluctuations of the order of a few monomers and Young moduli in the range 1–3 GPa

Selenium Nanoparticles as Potential Drug-Delivery Systems for the Treatment of Parkinson’s Disease

The development of efficient drug formulations for Parkinson’s disease (PD) treatment is challenged by achieving pharmacokinetic profiles, reduced side effects, and better permeability through the blood–brain barrier (BBB). As nanoparticles may facilitate the delivery of drugs in the brain due to their high-loading capacity and ability to cross biological barriers, we designed two different types of selenium nanoparticles (SeNPs) that may increase the transport of drugs across the BBB and may act as antioxidants at the site of action. The SeNPs were functionalized with polyvinylpyrrolidone (PVP) and polysorbate 20 (Tween) and characterized in terms of their size, size distribution, shape, surface charge, and colloidal stability in relevant biological media. Their drug-loading capacity was tested using dopamine and l-DOPA as therapeutically active agents for PD. Thermodynamic analysis revealed that binding processes occurred spontaneously through hydrogen bond/van der Waals interactions or electrostatic interactions. The strongest interaction was observed between PVP-SeNPs and l-DOPA or dopamine, which was characterized by a binding constant several orders of magnitude higher than for Tween-SeNPs. However, the addition of human transferrin as a model plasma protein significantly reduced this difference, which indicates the crucial role of protein corona formation in the design of drug nanodelivery systems. In vitro evaluation by cell-free and cellular transwell models showed efficient internalization of SeNP-loaded l-DOPA/dopamine by human endothelial brain cells, while facilitated BBB permeability for l-DOPA, and dopamine was achieved using PVP-SeNPs. Overall, the high potential of SeNPs as drug-delivery vehicles in PD treatment was demonstrated

Selenium Nanoparticles as Potential Drug-Delivery Systems for the Treatment of Parkinson’s Disease

The development of efficient drug formulations for Parkinson’s disease (PD) treatment is challenged by achieving pharmacokinetic profiles, reduced side effects, and better permeability through the blood–brain barrier (BBB). As nanoparticles may facilitate the delivery of drugs in the brain due to their high-loading capacity and ability to cross biological barriers, we designed two different types of selenium nanoparticles (SeNPs) that may increase the transport of drugs across the BBB and may act as antioxidants at the site of action. The SeNPs were functionalized with polyvinylpyrrolidone (PVP) and polysorbate 20 (Tween) and characterized in terms of their size, size distribution, shape, surface charge, and colloidal stability in relevant biological media. Their drug-loading capacity was tested using dopamine and l-DOPA as therapeutically active agents for PD. Thermodynamic analysis revealed that binding processes occurred spontaneously through hydrogen bond/van der Waals interactions or electrostatic interactions. The strongest interaction was observed between PVP-SeNPs and l-DOPA or dopamine, which was characterized by a binding constant several orders of magnitude higher than for Tween-SeNPs. However, the addition of human transferrin as a model plasma protein significantly reduced this difference, which indicates the crucial role of protein corona formation in the design of drug nanodelivery systems. In vitro evaluation by cell-free and cellular transwell models showed efficient internalization of SeNP-loaded l-DOPA/dopamine by human endothelial brain cells, while facilitated BBB permeability for l-DOPA, and dopamine was achieved using PVP-SeNPs. Overall, the high potential of SeNPs as drug-delivery vehicles in PD treatment was demonstrated