A new anterograde trans-synaptic tracer based on Sindbis virus

Mapping neural circuits is critical for understanding the structure and function of the nervous system.Engineered viruses are a valuable tool for tracing neural circuits.However,current tracers do not fully meet the needs for this approach because of various drawbacks,such as toxicity and characteristics that are difficult to modify.Therefore,there is an urgent need to develop a new tracer with low toxicity and that allows for long-term studies.In this study,we constructed an engineered Sindbis virus(SINV)expressing enhanced green fluorescent protein(EGFP)reporter gene(SINV-EGFP)and found that it had no significant difference in biological characterization compared with the wild-type Sindbis virus in BHK-21 cells and neurons in vitro.We injected the virus into the visual circuit of mouse brain and found that the virus infected neurons in the local injected site and anterogradely spread in the neural circuits.Although the efficiency of transmission was limited,the findings demonstrate that SINV can be used as a new anterograde tracer to map neural circuits in mouse brain and that it spreads exclusively in the anterograde direction.Further,use of SINV in mouse brain research will provide longer time windows for circuit tracing than is possible with herpes simplex virus and vesicular stomatitis virus tracers.

Oxygen-deficient tungsten oxide nanoflowers for dynamically tunable near-infrared light transmittance of smart windows

Electrochromic smart windows have attracted much attention in energy-saving buildings because of their ability to selectively modulate visible(VIS)and near-infrared(NIR)light transmittance.As is known,the NIR region accounts for about 50%of the total solar radiation.Therefore,reducing the NIR transmittance of windows will play a crucial role in reducing the energy consumption of buildings.However,for most of the reported electrochromic materials(ECMs)-based windows,it remains a longlasting challenge about how to achieve a low NIR transmittance during the past decades.In this work,we synthesize oxygendeficient tungsten oxide(WO_(3−x))nanoflowers(NFs)by a simple and efficient method that is facile for their mass production.The WO_(3−x)NFs exhibit low NIR transmittance of only 4.11%,0.60%,and 0.19%at 1200,1600,and 1800 nm,respectively,due to the localized surface plasmon resonance(LSPR)effect.Besides,the WO_(3−x)NFs exhibit an excellent dual-band modulating ability for both VIS and NIR light.They are able to operate in three distinct modes,including a bright mode,a cool mode,and a dark mode.Moreover,the WO_(3−x)NFs exhibit a fast bleaching/coloring time(1.54/6.67 s),and excellent cycling stability(97.75%of capacity retention after 4000 s).