Nanoscale Generation of Robust Solid Films from Liquid-Dispersed Nanoparticles via in Situ Atomic Force Microscopy: Growth Kinetics and Nanomechanical Properties.

Inorganic metal-oxide nanoparticles have been identified as candidate materials for replacing zinc dialkyldithiophosphate (ZDDP) antiwear additives in automotive lubricants due to their ability to form protective antiwear tribofilms. However, the nanoscale mechanisms that control the growth and properties of these tribofilms remain unknown. Here, we present the results of an in situ study of the kinetics of nanoparticle tribofilm growth using colloidal-probe atomic force microscopy (AFM). We report on the nucleation and growth of antiwear tribofilms formed with a dispersion of a novel zirconia (ZrO2) nanoparticle additive in low-viscosity oil. Tribofilms in this study are generated in situ at the lubricated nanoscale contact of the colloidal-probe AFM, which helps elucidate the effects of localized contact parameters on tribofilm nucleation and growth. The results strongly support that ZrO2 nanoparticle tribofilms grow through a process of stress-activated tribosintering, after removal of organic ligands that attached to the nanoparticles. In contrast to ZDDP-derived tribofilms, ZrO2 tribofilm growth occurs across temperatures from -25 to 100 °C. Nanomechanical properties of the resulting tribofilms are found to approach values for single-crystal and conventionally sintered macroscale structures, suggesting the potential for robust wear protection across a broader range of conditions than those where ZDDP is effective.

Examining childhood bullying and adolescent suicide: implications for school nurses.

Adolescent suicide is a preventable tragedy yet is still the third leading cause of death in young people of age 10-24. Contrary to the idea that childhood bullying is a normal part of growing up or a rite of passage, it is now correlated with adolescent suicidality. An integrative review of the contemporary, extant literature was conducted to examine the following question: Are adolescents who have been involved in childhood bullying or cyberbullying as victim, offender, or victim/offender at greater risk for suicidality than those who have not. It is important to empower school nurses with current and evidence-based information regarding childhood bullying and examine empirical science and tools to effectively address the current serious problem of adolescent suicide risk assessment and intervention.

A review and application of suicide prevention programs in high school settings.

Teen suicide is a terrible tragedy and is the third leading cause of death among high school children aged 14 to 19. School based intervention programs have been regarded as an effective and essential means of addressing this problem. A comprehensive review of the extant literature provides examination of the risk and protective factors of suicide in this age group, the development of these programs, the current state of the science and recommendations for enhanced assessment and intervention.