ABSTRACT
The search for Si-based anodes capable of undergoing low volume changes during electrochemical operation in rechargeable batteries is ample and active. Here we focus on crystalline Si24, a recently discovered open-cage allotrope of silicon, to thoroughly investigate its electrochemical performance using density functional theory calculations. In particular, we examine the phase stability of Na x Si24 along the whole composition range (0 ≤ x ≤ 4), volume and voltage changes during the (de)sodiation process, and sodium ion mobility. We show that Na x Si24 forms a solid solution with minimal volume changes. Yet sodium diffusion is predicted to be insufficiently fast for facile kinetics of Na-ion intake. Considering these advantages and limitations, we discuss the potential usefulness of Si24 as anode material for Na-ion batteries.
ABSTRACT
A synthetic antimicrobial peptide was identified as a possible candidate for the development of a new antibacterial drug. The peptide, SET-M33L, showed a MIC90 below 1.5 µM and 3 µM for Pseudomonas aeruginosa and Klebsiella pneumoniae, respectively. In in vivo models of P. aeruginosa infections, the peptide and its pegylated form (SET-M33L-PEG) enabled a survival percentage of 60-80% in sepsis and lung infections when injected twice i.v. at 5 mg/Kg, and completely healed skin infections when administered topically. Plasma clearance showed different kinetics for SET-M33L and SET-M33L-PEG, the latter having greater persistence two hours after injection. Bio-distribution in organs did not show significant differences in uptake of the two peptides. Unlike colistin, SET-M33L did not select resistant mutants in bacterial cultures and also proved non genotoxic and to have much lower in vivo toxicity than antimicrobial peptides already used in clinical practice. The characterizations reported here are part of a preclinical development plan that should bring the molecule to clinical trial in the next few years.