Efficient utilization of Al2O3 as structural promoter of Fe into 2 and 3 steps chemical looping hydrogen process. Pure H2 production from ethanol

Chemical Looping Hydrogen (CLH) allows the direct production of pure hydrogen exploiting the redox properties of Fe, with high flexibility on the type of reductant used. In this work, a highly pure hydrogen stream suitable for the direct use into Proton Exchange membrane Fuel Cells was produced, using bioethanol as renewable fuel. The influence of both redox temperature (675°C–750 °C) and chemical composition of the Fe-based particles (2 wt% and 40 wt% of alumina added) on the carbon formation rate during reduction step was also deeply analyzed. Al2O3 changed both FexOy redox kinetics and equilibrium phases, leading to a complete iron deactivation at high Al2O3 concentration. The addition of an air oxidation step (3 steps CLH) is fundamental to restore the redox activity, with a constant efficiency of about 30% at 750 °C for 10 cycles. Furthermore, Al2O3 promotes the ethanol conversion into carbon, undermining the hydrogen purity

Penetratin, a Potentially Powerful Absorption Enhancer for Noninvasive Intraocular Drug Delivery

Intraocular drug delivery is extraordinarily hampered by the impermeability of defensive barriers of the eye. In this study, the ocular permeability of fluorophore-labeled cell-penetrating peptides (CPPs), including penetratin, TAT, low molecular weight protamine, and poly­(arginine)₈, was investigated based on multilevel evaluations. The human conjunctival epithelial cell (NHC) was exposed to various CPPs to determine the cytotoxicity and cellular uptake. <i>Ex vivo</i> studies with rabbit cornea were performed using side-by-side diffusion chambers to evaluate the apparent permeability coefficients and acute tissue tolerance of the CPP candidates. Among all examined CPPs, penetratin shows an outstanding cellular uptake, by increasing more than 16 and 25 times at low and high concentrations, compared to the control peptide poly­(serine)₈ respectively. Additionally, the permeability of penetratin across excised cornea is 87.5 times higher in comparison with poly­(serine)₈. More importantly, after instilled in the conjunctival sac of rat eyes, fluorophore-labeled penetratin displayed a rapid and wide distribution in both anterior and posterior segment of the eye, and could be observed in the corneal epithelium and retina lasting for at least 6 h. Interestingly, penetratin showed the lowest ocular cell and tissue toxicities among all examined CPPs. The high ocular permeability of penetratin could be attributed to its amphipathicity and spatial conformation determined by circular dichroism. Taken together, these data demonstrate that penetratin is potentially useful as an absorption enhancer for intraocular drug delivery