RESUMO
We theoretically propose and experimentally realize a new configuration of a photonic Chern topological insulator (PCTI) composed of a two-dimensional square-hexagon lattice gyromagnetic photonic crystal immersed in an external magnetic field. This PCTI possesses five distinct types of edges and all of them allowed the propagation of truly one-way edge states. We proceeded to utilize this special PCTI to design topological transmission lines of various configurations with sharp turns. Although the wave impedances of the edge states on both sides of the intersections in these transmission lines were very different, definitely no back reflection occurred and no mode-mixing problems and impedance-mismatching issues at the intersections were present, leading to topological resistance-free one-way transport in the whole transmission line network. Our results enrich the geometric and physical means and infrastructure to construct one-way transport and bring about novel platforms for developing topology-driven resistance-free photonic devices.
RESUMO
A carrier-free CRISPR/Cas9 ribonucleoprotein delivery strategy for genome editing mediated by a cold atmospheric plasma (CAP) is described. The CAP is promising in many biomedical applications due to efficient production of bioactive ionized species. The MCF-7 cancer cells after CAP exposure exhibit increased extracellular reactive oxygen and nitrogen species (RONS) and altered membrane potential and permeability. Hence, transmembrane transport of Ca2+ into the cells increases and accelerates ATP hydrolysis, resulting in enhanced ATP-dependent endocytosis. Afterwards, the increased Ca2+ and ATP contents promote the release of cargo into cytoplasm due to the enhanced endosomal escape. The increased membrane permeability also facilitates passive diffusion of foreign species across the membrane into the cytosol. After CAP exposure, the MCF-7 cells incubated with Cas9 ribonucleoprotein (Cas9-sgRNA complex, Cas9sg) with a size of about 15 nm show 88.9% uptake efficiency and 65.9% nuclear import efficiency via passive diffusion and ATP-dependent endocytosis pathways. The efficient transportation of active Cas9sg after the CAP treatment leads to 21.7% and 30.2% indel efficiencies in HEK293T and MCF-7 cells, respectively. This CAP-mediated transportation process provides a simple and robust alternative for the delivery of active CRISPR/Cas9 ribonucleoprotein. Additionally, the technique can be extended to other macro-biomolecules and nanomaterials to cater to different biomedical applications.
RESUMO
The maneuver of small bubbles in a programmed way will advance numerous processes, including gas evolution reaction and aeration. Unlike in-air droplets, rapidly rising bubbles in liquid medium can hardly be steered through interaction with solid substrates, causing difficulties in maneuvering bubbles. We pattern and lubricate nanoporous substrates with regions of contrasting wettability that is similar to the back of Namib desert beetles and subsequently immerse the lubricated surface underwater to spontaneously form spatially patterned Nepenthes-inspired slippery surfaces after the dewetting of lubricants. As a result, bubbles are confined on lubricant-infused surfaces, with their high mobility well preserved. The interfacial states of attached bubbles are analyzed, and their dynamic sliding velocities are quantified. Using the lubricated patterned surfaces, we further demonstrate the predefined motion of bubbles driven by buoyancy at a small tiling angle, as well as a self-propulsion of bubbles driven by surface tension force at a tilting angle of 0°, respectively. The spatially lubricated surfaces simplify gas handling in liquid medium and have potential applications in fields where bubble handling is crucial.
RESUMO
No Brasil, estudantes, crianças de até quatro anos de idade e idosos com 65 anos ou mais têm direito a descontos parciais ou totais em viagens urbanas nos sistemas de transporte público. Esses descontos não são cobertos por fundos públicos, mas sim por subsídio cruzado cobrado dos demais usuários que pagam a tarifa cheia. Neste estudo, são estimados os efeitos do envelhecimento populacional sobre o preço das passagens do transporte público nas próximas quatro décadas na Região Metropolitana de São de Paulo (RMSP), a maior região metropolitana do país. As análises são baseadas nos dados da Pesquisa Origem-Destino, realizada em 2007 na RMSP, e nas projeções demográficas elaboradas pelo IBGE e pela Fundação Seade para 2020, 2030 e 2050. Considerando os diferentes períodos de projeção populacional, adaptou-se a técnica de padronização direta para simular as mudanças esperadas na composição das viagens do sistema de transporte, em termos de passageiros pagantes e não pagantes. Os resultados indicam que, no curto prazo (2020), o envelhecimento populacional estimado para ocorrer na RMSP teria efeito modesto sobre o número total e a composição etária das viagens realizadas no transporte público da região. No médio e longo prazos, contudo, o crescimento previsto na proporção de passageiros com gratuidades poderia ocasionar aumento no sobrepreço da tarifa, com elevação de seu valor em cerca de 10% e de 20%, caso seja mantido o mecanismo de subsídios cruzados...
In Brazil, students, children under four years of age and people aged 65 and over are entitled to partial or full concessions on urban travel in public transport systems. These discounts are not covered by public funding, but rather via cross-subsidization charged to the other service users who pay the full fare. In this study, the effects of population aging on public transport fares for the next four decades in the metropolitan region of São Paulo (MRSP), the largest metropolitan area in Brazil, are estimated. The analyses in this paper are based on data from the Pesquisa Origem-Destino (Origin-Destination Survey), carried out in 2007 in the MRSP, and on official population projections developed by IBGE (the Brazilian Institute of Geography and Statistics) and Fundação Seade (the Seade Foundation) for the years 2020, 2030 and 2050. Considering the different periods of population projection, the technique of direct standardization to simulate expected changes in the composition of public transport trips was utilized, in terms of paying and non-paying passengers. The results indicate that, in the short term (2020), population aging expected to occur in the MRSP should have a modest effect on the total number and age composition of public transport trips in the region. However, if the current cross-subsidization mechanism is maintained, the expected growth in the percentage of non-paying passengers could result in an increase in fares by about 10% and 20% in the medium and long terms...
En Brasil, los estudiantes, los niños menores de 4 años y las personas de 65 años o más tienen derecho a descuentos parciales o totales en los viajes urbanos en los sistemas de transporte público. Estos descuentos no son cubiertos por fondos públicos, sino por un subsidio cruzado cobrado a los demás usuarios de los servicios que pagan la tarifa completa. En este estudio, se estiman los efectos del envejecimiento de la población sobre el precio de los pasajes del transporte público en las próximas cuatro décadas en la Región Metropolitana de São Paulo (RMSP), la mayor región metropolitana del país. Los análisis se basan en los datos de la Encuesta de Origen-Destino realizada en 2007 en la RMSP y en las proyecciones demográficas elaboradas por el IBGE y por la Fundación SEADE para 2020, 2030 y 2050. Teniendo en cuenta los diferentes escenarios de proyección de la población, se utiliza la técnica de estandarización directa para simular los cambios esperados en la composición de los viajes del sistema de transporte en términos de pasajeros que pagan y que no lo hacen. Los resultados indican que, en el corto plazo (2020), el envejecimiento de la población estimado en la RMSP tendría un efecto modesto sobre el número total y la composición por edades de los viajes realizados en el transporte público de la región. En el mediano y el largo plazo, sin embargo, el aumento previsto de la proporción de pasajeros con el beneficio de la gratuidad podría causar un incremento del sobreprecio de la tarifa, con una elevación de su valor de entre el 10% y el 20%, en caso de mantenerse el mecanismo de subsidio cruzado...
