13,405 research outputs found
Ultra-fast self-assembly and stabilization of reactive nanoparticles in reduced graphene oxide films.
Nanoparticles hosted in conductive matrices are ubiquitous in electrochemical energy storage, catalysis and energetic devices. However, agglomeration and surface oxidation remain as two major challenges towards their ultimate utility, especially for highly reactive materials. Here we report uniformly distributed nanoparticles with diameters around 10 nm can be self-assembled within a reduced graphene oxide matrix in 10 ms. Microsized particles in reduced graphene oxide are Joule heated to high temperature (∼1,700 K) and rapidly quenched to preserve the resultant nano-architecture. A possible formation mechanism is that microsized particles melt under high temperature, are separated by defects in reduced graphene oxide and self-assemble into nanoparticles on cooling. The ultra-fast manufacturing approach can be applied to a wide range of materials, including aluminium, silicon, tin and so on. One unique application of this technique is the stabilization of aluminium nanoparticles in reduced graphene oxide film, which we demonstrate to have excellent performance as a switchable energetic material
Optical excitation and detection of neuronal activity
Optogenetics has emerged as an exciting tool for manipulating neural
activity, which in turn, can modulate behavior in live organisms. However,
detecting the response to the optical stimulation requires electrophysiology
with physical contact or fluorescent imaging at target locations, which is
often limited by photobleaching and phototoxicity. In this paper, we show that
phase imaging can report the intracellular transport induced by optogenetic
stimulation. We developed a multimodal instrument that can both stimulate cells
with high spatial resolution and detect optical pathlength changes with
nanometer scale sensitivity. We found that optical pathlength fluctuations
following stimulation are consistent with active organelle transport.
Furthermore, the results indicate a broadening in the transport velocity
distribution, which is significantly higher in stimulated cells compared to
optogenetically inactive cells. It is likely that this label-free, contactless
measurement of optogenetic response will provide an enabling approach to
neuroscience.Comment: 20 pages, 5 figure
Development of advanced digital techniques for data acquisition processing and communication Interim scientific report
Image correlation and computerized simulation applied to data acquisition and imaging technique
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