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Background and aims: With the prevalence of e‐cigarette use among Australian youth increasing significantly in recent years, greater attention is being paid to encouraging and supporting cessation. However, research to inform such efforts is lacking. The present study sought to (i) measure desire to quit e‐cigarette use and actual quitting attempts among young Australians and (ii) explore correlates of quitting‐related cognitions and behaviours. Design, setting and participants: This was a cross‐sectional on‐line survey conducted in Australia. The participants were 14−25‐year‐old e‐cigarette users (n = 602; 53% women). Measurements: Desire to quit vaping and attempts to quit vaping were the primary dependent variables. The independent variables included several individual (e.g. harm perceptions, perceived appeal of vapes), social (descriptive norms) and environmental (e.g. ease of e‐cigarette access) factors. Findings A majority of respondents (61%) expressed a desire to quit vaping, and just over half (55%) had made a quit attempt. Finding vapes easy to access was associated with both a lack of desire [odds ratio (OR) = 0.71] and attempts to quit (OR = 0.77), while self‐reported addiction to vaping (OR = 1.42 and OR = 3.11) and perceiving vaping to be associated with mental health risks (OR = 1.30 and OR = 1.40) were positively correlated with these variables. Perceiving that vaping is common among people of one's age (OR = 0.82) and finding vapes appealing (OR = 0.55) were associated with a lack of desire to quit, while perceiving vaping to have physical health risks was positively associated with quitting desire (OR = 1.58). School‐based education on vaping was associated with reporting an attempt/s to quit (OR = 0.47). Conclusions: This survey of young Australian e‐cigarette users suggests a high level of desire to quit using e‐cigarettes and attempts to quit. Increasing knowledge regarding the physical and mental health risks associated with e‐cigarette use may assist with promoting quitting‐related intentions. Changing social norms, reducing the accessibility of e‐cigarettes and reducing the appeal of the products also constitute potential means of increasing the desire to quit. [ABSTRACT FROM AUTHOR]

Entamoeba histolytica is the causative agent of amoebiasis, a potentially fatal diarrhoeal disease in the developing world. The parasite was named "histolytica" for its ability to destroy host tissues, which is probably driven by direct killing of human cells. The mechanism of human cell killing has been unclear, although the accepted model was that the parasites use secreted toxic effectors to kill cells before ingestion. Here we report the discovery that amoebae kill by ingesting distinct pieces of living human cells, resulting in intracellular calcium elevation and eventual cell death. After cell killing, amoebae detach and cease ingestion. Ingestion of human cell fragments is required for cell killing, and also contributes to invasion of intestinal tissue. The internalization of fragments of living human cells is reminiscent of trogocytosis (from Greek trogo, nibble) observed between immune cells, but amoebic trogocytosis differs because it results in death. The ingestion of live cell material and the rejection of corpses illuminate a stark contrast to the established model of dead cell clearance in multicellular organisms. These findings change the model for tissue destruction in amoebiasis and suggest an ancient origin of trogocytosis as a form of intercellular exchange.

Mastoparans are cationic peptides with multifunctional pharmacological properties. Mastoparan-R1 and mastoparan-R4 were computationally designed based on native mastoparan-L from wasps and have improved therapeutic potential for the control of bacterial infections. Here, we evaluated whether these peptides maintain their activity against Escherichia coli strains under a range of salt concentrations. We found that mastoparan- R1 and mastoparan-R4 preserved their activity under the conditions tested, including having antibacterial activities at physiological salt concentrations. The overall structure of the peptides was investigated using circular dichroism spectroscopy in a range of solvents. No significant changes in secondary structure were observed (random coil in aqueous solutions and a-helix in hydrophobic and anionic environments). The three-dimensional structures of mastoparan-R1 and mastoparan-R4 were elucidated through nuclear magnetic resonance spectroscopy, revealing amphipathic a-helical segments for Leu3-Ile13 (mastoparan-R1) and Leu3-Ile14 (mastoparan- R4). Possible membrane-association mechanisms for mastoparan-R1 and mastoparan-R4 were investigated through surface plasmon resonance and leakage studies with synthetic POPC and POPC/POPG (4:1) lipid bilayers. Mastoparan-L had the highest affinity for both membrane systems, whereas the two analogs had weaker association, but improved selectivity for lysing anionic membranes. This finding was also supported by molecular dynamics simulations, in which mastoparan-R1 and mastoparan-R4 were found to have greater interactions with bacteria-like membranes compared with model mammalian membranes. Despite having a few differences in their functional and structural profiles, the mastoparan-R1 analog stood out with the highest activity, greater bacteriostatic potential, and selectivity for lysing anionic membranes. This study reinforces the potential of mastoparan-R1 as a drug candidate. [ABSTRACT FROM AUTHOR]

The characterization and evaluation of three novel 5-[mico]m HPLC column packings, prepared using ethyl-bridged hybrid organic/inorganic materials, is described. These highly spherical hybrid particles, which vary in specific surface area (140, 187, and 270 [m.sup.2]/g) and average pore diameter (185, 148, and 108 [Angstrom]), were characterized by elemental analysis, SEM, and nitrogen sorption analysis and were chemically modified in a two-step process using octadecyltrichlorosilane and trimethylchlorosilane. The resultant bonded materials had an octadecyl surface concentration of 3.17-3.35 [micro]mol/[m.sup.2], which is comparable to the coverage obtained for an identically bonded silica particle (3.44 [micro]mol/[m.sup.2]) that had a surface area of 344 [m.sup.2]/g. These hybrid materials were shown to have sufficient mechanical strength under conditions normally employed for traditional reversed-phase HPLC applications, using a high-pressure column flow test. The chromatographic properties of the [C.sub.18] bonded hybrid phases were compared to a [C.sub.18] bonded silica using a variety of neutral and basic analytes under the same mobile-phase conditions. The hybrid phases exhibited similar selectivity to the silica-based column, yet had improved peak tailing factors for the basic analytes. Column retentivity increased with increasing particle surface area. Elevated pH aging studies of these hybrid materials showed dramatic improvement in chemical stability for both bonded and unbonded hybrid materials compared to the [C.sub.18] bonded silica phase, as determined by monitoring the loss in column efficiency through 140-h exposure to a pH 10 triethylamine mobile phase at 50 [degrees]C.