Emergence of Selectivity in Inherently Nonselective Gold Nanoparticles Through Preferential Breaking of Interparticle Interactions

We demonstrate a fundamentally unique identification strategy to impart selectivity to a traditionally and inherently nonselective carboxylate-functionalized gold-nanoparticles ([-] AuNPs), without the aid of any analyte specific ligands. The common practice is to use the ability of divalent ions to trigger the aggregation process in a kinetically trapped dispersed solution of [-] AuNPs. Aggregation of NPs being a thermodynamically favourable process will result in a uniform and nonselective turn-off response from most of the strongly binding divalent ions. Our approach is to use the abilities of various divalent ions to break a thermodynamically stable inter-nanoparticle precipitates containing [+] and [-] AuNPs (nanoionic precipitates), as the means of identification. Importantly both [+] and [-] AuNPs, independently, were ‘blind’ in terms of selectivity towards divalent ions. Remarkably, a hybrid-system composed of such nonselective nanoparticles was able to discriminate between the hard-to-distinguish pair of Pb2+ and Cd2+ ions. The rationale is that only the strongest of strongly binding ions will be able to break the interactions between the NP precipitates (thermodynamically stable state) and re-disperse them back in solution (kinetically trapped state). This is in stark contrast with the conventional idea of forming an interaction between NPs and divalent ions, with the help of analyte-specific ligands.</p

Optimising refugee children's health/wellbeing in preparation for primary and secondary school : a qualitative inquiry

Background: Children from refugee backgrounds are less likely to access appropriate health and social care than non-refugee children. Our aim was to identify refugee children’s health/wellbeing strengths and needs, and the barriers and enablers to accessing services while preparing for primary and secondary school, in a low socioeconomic multicultural community in Australia. Method: Ten focus groups were facilitated with Arabic-speaking refugee parents of children aged 2–5 years (n = 11) or in first year secondary school (n = 22); refugee adolescents starting high school (n = 16); and key service providers to refugee families (n = 27). Vignettes about a healthy child and a child with difficulties guided the discussions. Data was thematically analysed and feedback sought from the community via the World Café method. Results: Personal resilience and strong family systems were identified as strengths. Mental health was identified as a complex primary need; and whilst refugees were aware of available services, there were issues in knowing how to access them. Opportunities for play/socialisation were recognised as unmet adolescent needs. Adults spoke of a need to support integration of “old” and “new” cultural values. Parents identified community as facilitating health knowledge transfer for new arrivals; whilst stakeholders saw this as a barrier when systems change. Most parents had not heard of early childhood services, and reported difficulty accessing child healthcare. Preschooler parents identified the family “GP” as the main source of health support; whilst parents of adolescents valued their child’s school. Health communication in written (not spoken) English was a significant roadblock. Differences in refugee family and service provider perceptions were also evident. Conclusions: Refugee families face challenges to accessing services, but also have strengths that enable them to optimise their children’s wellbeing. Culturally-tailored models of care embedded within GP services and school systems may assist improved healthcare for refugee families

Status of the ITER Ion Cyclotron H&CD system

The ongoing design of the ITER Ion Cyclotron Heating and Current Drive system (20 MW, 40-55 MHz) is rendered challenging by the wide spectrum of requirements and interface constraints to which it is subject, several of which are conflicting and/or still in a high state of flux. These requirements include operation over a broad range of plasma scenarios and magnetic fields (which prompts usage of wide-band phased antenna arrays), high radio-frequency (RF) power density at the first wall (and associated operation close to voltage and current limits), resilience to ELM-induced load variations, intense thermal and mechanical loads, long pulse operation, high system availability, efficient nuclear shielding, high density of antenna services, remote-handling ability, tight installation tolerances, and nuclear safety function as tritium confinement barrier. R&D activities are ongoing or in preparation to validate critical antenna components (plasma-facing Faraday screen, RF sliding contacts, RF vacuum windows), as well as to qualify the RF power sources and the transmission and matching components. Intensive numerical modeling and experimental studies on antenna mock-ups have been conducted to validate and optimize the RF design. The paper highlights progress and outstanding issues for the various system component