Design of problem-based learning activities in the field of microfluidics for 12- to 13-year-old participants—Small Plumbing!: empowering the next generation of microfluidic engineers

Public engagement activities based on microfluidics are being increasingly delivered and reported on in the literature. Here, we evaluate the success of a novel approach to microfluidics outreach recently undertaken with schoolchildren aged 12–13. Unlike previous work, a problem-based learning approach was adopted whereby participants were asked to design and test a microfluidic system to solve a research challenge. Our aim was to develop understanding of microfluidics design, manufacture and operation via involvement in the full engineering cycle of a product, from ideas to design, and from fabrication to test. This article demonstrates that problem-based learning is a successful method of public engagement with microfluidics, and we share our best practice, including activity design, supporting material produced for the project and an example case study detailing the types of chips produced by the participants. Furthermore, following an evaluation of the activity by all participants recommendations for delivery of this, or similar, activities are provided.     

Supportive Housing: Justifiable Paternalism?

Scholars have long draw on neoliberalism and paternalism as theoretical frameworks to argue that states have become less generous in providing welfare and housing resources. These theories similarly demonstrate that the resources that are provided are characterized by conditional exchanges, whereby welfare recipients and social housing tenants are required to comply with behavioural conditions. Theoretical critiques of state intervention influenced by neoliberalism and paternalism are broad, but they generally agree that conditional welfare approaches, including social housing, focus on changing individuals living in poverty themselves and not sufficiently changing policy, economic, social and institutional forces that underpin poverty. In light of these theories of state intervention, this article draws on an Australian qualitative study with tenants and service providers in supportive housing. The article shows that supportive housing is positioned as a significant intervention to not only house disadvantaged groups, but rather as an optimistic mechanism to directly improve disadvantaged people’s lives. The article argues that when coupled with long-term housing, a weak form of paternalist welfare for people who have experienced chronic homelessness can be justified.     

Non-linear dissolution mechanisms of sodium calcium phosphate glasses as a function of pH in various aqueous media

Phosphate glasses for bioresorbable implants display dissolution rates that vary significantly with composition, however currently their mechanisms of dissolution are not well understood. Based on this systematic study we present new insights into these mechanisms. Two-stage dissolution was observed, with time dependence initially parabolic and later linear, and a two-stage model was developed to describe this behaviour. Dissolution was accelerated by lower Ca concentration in the glass, and lower pH in the dissolution medium. A new dissolution mechanism is proposed, involving an initial stage where diffusion-controlled formation of a conversion layer occurs. Once the conversion layer is stabilised, layer dissolution reactions become rate-limiting. Under this mechanism the transition time is sensitive to the nature of the conversion layer and solution conditions. These results reveal the dependence of P₂O₅–CaO–Na₂O glass dissolution on solution pH, and provide new insight into the dissolution mechanisms, particularly regarding the transition between the two dissolution stages.     

Chitosan amphiphiles provide new drug delivery opportunities

Chitosan, an acid soluble and renewable biopolymer, was first studied as a drug delivery agent in 1990. This review focuses on the relatively newer self‐assembling chitosan amphiphiles and their use as drug delivery agents. Chitosan amphiphiles, first introduced in the late 1990s, are prepared by conjugating hydrophobic and sometimes additional hydrophilic units to chitosan. These amphiphiles self‐assemble in aqueous media at neutral pH to form micelles, with critical micellar concentrations (CMCs) ranging from 0.09 to 700 µg mL^?1. The CMCs depend on the actual molecular architecture, molecular weight and hydrophobic character, but are typically lower than the values reported for block copolymer amphiphiles. As well as linear amphiphiles in which chitosan is derivatised with hydrophobic pendant groups, new claw amphiphiles have been prepared in which chitosan amphiphiles radiate geometrically from a dendrimer core. These chitosan amphiphiles (linear and claw) have been exploited as drug delivery agents and they increase the oral bioavailability of hydrophobic drugs up to sixfold, deliver hydrophobic drugs to tumours, genes to the liver via the intravenous route, genes to the muscle via the intramuscular routes and small interfering RNAs to tumours via the intratumoural route. Chitosan amphiphile nanoparticles also deliver peptides to the brain via the intravenous and oral routes. © 2014 Society of Chemical Industry     

Vocal production in postpartum dairy cows: Temporal organization and association with maternal and stress behaviors

Mammalian vocalizations can encode contextual information in both the spectrographic components of their individual vocal units and in their temporal organization. Here we observed 23 Holstein-Friesian dairy cows immediately after birth during interactions with their calf and when their calf was separated to the other side of a fence line. We investigated whether the vocalizations emitted in these postpartum contexts would vary temporally. We also described the maternal and stress behaviors preceding and following postpartum vocal production using kinematic diagrams and characterized call sequence structure. The kinematic diagrams highlight the disruption of maternal responses caused by calf separation and show that behavioral and vocal patterns varied according to the cows' emotional states and proximity to the calf in both contexts. During calf interactions, cows mainly produced closed-mouth calls simultaneous to licking their calf, whereas an escalation of stress responses was observed during calf separation, with the cows approaching the fence line, becoming alert to the calf, and emitting more mixed and open-mouth calls. Call sequences were similarly structured across contexts, mostly containing repetitions of a single call type, with a mean interval of 0.57 s between calls and a greater cumulative vocalization duration, attributed to an increased number of vocal units per sequence. Overall, calf separation was associated with a greater proportion of calls emitted as a sequence (inverse of single isolated calls), a shorter interval between separate call sequences, and a greater number of vocal units per sequence, compared with calf interactions. These temporal vocal features varied predictably with the high stress expression from cows during calf separation and may represent temporal modulations of emotional expression. Despite the noisy farm soundscape, empirical call type and temporal vocal features were easy to measure; thus, findings could be applied to future cattle studies wishing to analyze vocalizations for on-farm welfare assessments.     

Management Levers for Product Platforms

Platforming has become an important means of cost-sharing among industrial products. However, many firms face systemic downward pressure on commonality, with the result that many platforms realize less commonality than intended. Past research has hypothesized that divergence is the result of conflicting tensions between product customization/optimization and cost control. This article investigates the control and incentive levers available to platform managers to shape the behavior of the organization when divergence opportunities arise. Management levers are drawn from a series of 12 industrial case studies, stemming from investigations of the causes of divergences. These management levers are categorized as technical levers, financial levers, and organizational levers. This article illustrates each of the management levers with examples from the case studies.     

The response of the adult and ATD heads to impacts onto a rigid surface

Given the high incidence of TBI, head injury has been studied extensively using both cadavers and anthropomorphic test devices (ATDs). However, few studies have benchmarked the response of ATD heads against human data. Hence, the objective of this study is to investigate the response of adult and ATD heads in impact, and to compare adult Hybrid III head responses to the adult head responses.