Two Major Medicinal Honeys Have Different Mechanisms of Bactericidal Activity

Honey is increasingly valued for its antibacterial activity, but knowledge regarding the mechanism of action is still incomplete. We assessed the bactericidal activity and mechanism of action of Revamil® source (RS) honey and manuka honey, the sources of two major medical-grade honeys. RS honey killed Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa within 2 hours, whereas manuka honey had such rapid activity only against B. subtilis. After 24 hours of incubation, both honeys killed all tested bacteria, including methicillin-resistant Staphylococcus aureus, but manuka honey retained activity up to higher dilutions than RS honey. Bee defensin-1 and H2O2 were the major factors involved in rapid bactericidal activity of RS honey. These factors were absent in manuka honey, but this honey contained 44-fold higher concentrations of methylglyoxal than RS honey. Methylglyoxal was a major bactericidal factor in manuka honey, but after neutralization of this compound manuka honey retained bactericidal activity due to several unknown factors. RS and manuka honey have highly distinct compositions of bactericidal factors, resulting in large differences in bactericidal activity

Writing in Britain and Ireland, c. 400 to c. 800

No abstract available

Reduced density matrices and entanglement entropy in free lattice models

We review the properties of reduced density matrices for free fermionic or bosonic many-particle systems in their ground state. Their basic feature is that they have a thermal form and thus lead to a quasi-thermodynamic problem with a certain free-particle Hamiltonian. We discuss the derivation of this result, the character of the Hamiltonian and its eigenstates, the single-particle spectra and the full spectra, the resulting entanglement and in particular the entanglement entropy. This is done for various one- and two-dimensional situations, including also the evolution after global or local quenches.Comment: 33 pages, 18 figures, minor changes, references added. Review article for the special issue "Entanglement entropy in extended systems" in J. Phys.

Highly Active and Selective Cu-ZnO based Catalyst for Methanol and Dimethyl Ether Synthesis via CO₂ Hydrogenation

Highly active and selective Cu-ZnO based catalysts with high BET surface areas and Cu surface areas were prepared using the co-precipitation method. The Cu-ZnO based catalysts were systematically characterized and studied for methanol synthesis. Bifunctional catalysts, composed of Cu-ZnO based catalysts and HZSM-5 were studied for one-step dimethyl ether (DME) synthesis via CO2 hydrogenation. The effects of catalyst preparation conditions, reaction temperature, and pressure on methanol and DME synthesis were investigated and the optimum reaction conditions were determined. The optimized catalyst showed a BET surface area of 128 m2/g and a Cu surface area of over 59.3 m2/g, and demonstrated a high catalytic activity for CO2 hydrogenation. A bifunctional catalyst, prepared by a synthesized Cu-ZnO catalyst and HZSM-5, showed a high DME selectivity in one-step CO2 hydrogenation and methanol dehydration. The high activity and selectivity of the catalysts were attributed to the microstructure of the catalysts, which can be greatly affected by the catalyst preparation process. A long-term stability test showed a considerable decrease in activity within the first 20 h; however, the CO2 conversion (21.4%) and DME selectivity (55.5%) were still very high after 100 h