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We explore the potential of DNA nanotechnology for developing novel optical voltage sensing nanodevices that convert a local change of electric potential into optical signals. As a proof-of-concept of the sensing mechanism, we assembled voltage responsive DNA origami structures labeled with a single pair of FRET dyes. The DNA structures were reversibly immobilized on a nanocapillary tip and underwent controlled structural changes upon application of an electric field. The applied field was monitored through a change in FRET efficiency. By exchanging the position of a single dye, we could tune the voltage sensitivity of our DNA origami structure, demonstrating the flexibility and versatility of our approach. The experimental studies were complemented by coarse-grained simulations that characterized voltage-dependent elastic deformation of the DNA nanostructures and the associated change in the distance between the FRET pair. Our work opens a novel pathway for determining the mechanical properties of DNA origami structures and highlights potential applications of dynamic DNA nanostructures as voltage sensors.
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ADN/química , Electricidad , Transferencia Resonante de Energía de Fluorescencia/instrumentación , Colorantes Fluorescentes/química , Nanoestructuras/química , Nanotecnología/instrumentación , Técnicas Biosensibles/instrumentación , Electrodos , Diseño de Equipo , Transporte Iónico , Nanoestructuras/ultraestructura , Conformación de Ácido NucleicoRESUMEN
The roles of bridging actors in emergency response networks can be important to disaster response outcomes. This paper is based on an evaluation of wildfire preparedness and response networks in 21 large-scale wildfire events in the wildland-urban interface near national forests in the American Northwest. The study investigated how key individuals in responder networks anticipated seeking out specific people in perceived bridging roles prior to the occurrence of wildfires, and then captured who in fact assumed these roles during actual large-scale events. It examines two plausible, but contradictory, bodies of theory-similarity and dissimilarity-that suggest who people might seek out as bridgers and who they would really go to during a disaster. Roughly one-half of all pre-fire nominations were consistent with similarity. Yet, while similarity is a reliable indicator of how people expect to organise, it does not hold up for how they organise during the real incident.
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Redes Comunitarias/organización & administración , Planificación en Desastres/organización & administración , Incendios , Humanos , Noroeste de Estados UnidosRESUMEN
Organic aerosols (OAs) play important roles in multiple atmospheric processes, including climate change, and can impact human health. The physico-chemical properties of OAs are important for all these processes and can evolve through reactions with various atmospheric components, including oxidants. The dynamic nature of these reactions makes it challenging to obtain a true representation of their composition and surface chemistry. Here we investigate the microscopic viscosity of the model OA composed of squalene, undergoing chemical aging. We employ Fluorescent Lifetime Imaging Microscopy (FLIM) in conjunction with viscosity sensitive probes termed molecular rotors, in order to image the changes in microviscosity in real time during oxidation with ozone and hydroxyl radicals, which are two key oxidising species in the troposphere. We also recorded the Raman spectra of the levitated particles to follow the reactivity during particle ozonolysis. The levitation of droplets was achieved via optical trapping that enabled simultaneous levitation and measurement via FLIM or Raman spectroscopy and allowed the true aerosol phase to be probed. Our data revealed a very significant increase in viscosity of the levitated squalene droplets upon ozonolysis, following their transformation from the liquid to solid phase that was not observable when the oxidation was carried out on coverslip mounted droplets. FLIM imaging with sub-micron spatial resolution also revealed spatial heterogeneity in the viscosity distribution of oxidised droplets. Overall, a combination of molecular rotors, FLIM and optical trapping is able to provide powerful insights into OA chemistry and the microscopic structure that enables the dynamic monitoring of microscopic viscosity in aerosol particles in their true phase.
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Background: Embedding Public and Patient Involvement (PPI) in postgraduate research has been recognized as an important component of post-graduate training, providing research scholars with an awareness and a skillset in an area which prepares them for future roles as healthcare researchers. Improving Pathways for Acute STroke And Rehabilitation (iPASTAR) is a structured PhD training program [Collaborative Doctoral Award (CDA)] which aims to design a person-centered stroke pathway throughout the trajectory of stroke care, to optimize post-stroke health and wellbeing. PPI is embedded at all stages. Purpose: The iPASTAR research programme was strongly informed by a round-table PPI consultation process with individuals who experienced stroke and who provided broad representation across ages, gender, geographical locations (urban and rural) and the PhD themed areas of acute care, early supported discharge and lifestyle-based interventions after stroke. Four PhD scholars taking part in the CDA-iPASTAR now work collaboratively with four stroke champions, supported by a wider PPI advisory panel. Methods: This study will evaluate the process and impact of embedding PPI during a PhD program. We will conduct a longitudinal mixed-methods evaluation, conducting focus groups at 24, 36, and 48 months to explore the experiences of the key stakeholders involved. The participants will include PhD scholars, PPI partners (PPI Advisory Group and PPI Champions), PhD supervisors and a PPI manager. An independent researcher will conduct the evaluation. We will include focus groups, individual interviews and participant reflections. Qualitative data will be analyzed using thematic and content analysis, quantitative data will be analyzed using descriptive statistics. Discussion: PPI and patient voice initiatives bring together researchers, family, and people with health care issues into meaningful dialogue and allow the development of a patient-voice learning network. Embedding PPI training within a PhD program can build meaningful capacity in PPI partnerships in stroke research.
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The viscosity of atmospheric aerosol particles affects a number of key physical and chemical particle properties, such as composition and reactivity. However, determination of the microscopic viscosity of aerosol particles is a non-trivial task. We report a new method of imaging viscosity in a variety of model aerosol systems, based on a fluorescence lifetime determination of viscosity-sensitive fluorophores termed molecular rotors. We report the viscosity changes associated with the relative humidity dependent hygroscopicity of NaCI and sucrose aerosols, as well as reaction dependent changes in viscosity during ozonolysis of oleic acid aerosols. The Fluorescence Lifetime Imaging Microscopy (FLIM) of molecular rotors shows great promise in understanding important fundamental aerosol properties, which can be both time-dependent and spatially variable through the aerosol particle.