Measuring Nanoparticle Attachment Efficiency in Complex Systems.

As process-based environmental fate and transport models for engineered nanoparticles are developed, there is a need for relevant and reliable measures of nanoparticle behavior. The affinity of nanoparticles for various surfaces (α) is one such measure. Measurements of the affinity of nanoparticles obtained by flowing particles through a porous medium are constrained by the types of materials or exposure scenarios that can be configured into such column studies. Utilizing glass beads and kaolinite as model collector surfaces, we evaluate a previously developed mixing method for measuring nanoparticle attachment to environmental surfaces, and validate this method with an equivalent static column system over a range of organic matter concentrations and ionic strengths. We found that, while both impacted heteroaggregation rates in a predictable manner when varied individually, neither dominated when both parameters were varied. The theory behind observed nanoparticle heteroaggregation rates (αßB) to background particles in mixed systems is also experimentally validated, demonstrating both collision frequency (ß) and background particle concentration (B) to be independent for use in fate modeling. We further examined the effects of collector particle composition (kaolinite vs glass beads) and nanoparticle surface chemistry (PVP, citrate, or humic acid) on α, and found a strong dependence on both.

Developing a shared understanding of translational science within CTSA hubs through facilitated retreats: A case study.

Translation of critical and broadly impactful health advancements is stymied by insufficient scientific scrutiny of barriers and roadblocks in the process. The Clinical & Translational Science Award (CTSA) funding opportunity announcement released in July 2021 makes clear the distinction between translational research and translational science (TS) and urges a shift from the former to the latter. This represents a significant shift in the overall scientific direction of the CTSA program and necessitates corresponding shifts in CTSA hub operations. To better support TS, the Team Science Core of the Duke CTSA hub designed and facilitated a virtual retreat for hub personnel that (1) enabled organizational learning about TS and (2) identified anticipated challenges and opportunities. A post-retreat survey was utilized to assess the degree to which the retreat met its stated goals. Our survey received a 62% response rate; 100% of respondents would recommend the session to others. Respondents also reported gains in all areas assessed, with evidence for greater understanding of TS and increased perspective of the value and relevance of TS. In this paper, we provide a roadmap for designing and implementing facilitated TS retreats, which we argue is a key step in TS capacity building through workforce development.