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BACKGROUND: Pulmonary fibrosis (PF) is a chronic, progressive, and irreversible heterogeneous disease of lung interstitial tissue. To combat progression of PF, new drugs are required to be developed. Rhizoma coptidis (COP), one of the main alkaloids of Coptis chinensis, is a traditional herbal medicine used to treat various inflammatory diseases. OBJECTIVE: To investigate the possible effects of Coptisine (Cop) on the growth, inflammation, as well as FMT of TNF-ß1-induced HFL1 cells and uncover the mechanism. MATERIAL AND METHODS: Human fetal lung fibroblast 1 (HFL1) was induced using 6ng/mL TGF-ß1 as a model of pulmonary fibrosis. CCK-8, Brdu, and transwell assays indicated the effects on cell growth as well as motility. qPCR and the corresponding kits indicted the effects on cell inflammation. Immunoblot showed the effects on FMT and further confirmed the mechanism. RESULTS: Coptisine inhibits excessive growth as well as motility of TNF-ß1-induced HFL1 cells. It further inhibits inflammation and ROS levels in TNF-ß1-induced HFL1 cells. Coptisine inhibits the FMT process of TNF-ß1-induced HFL1 cells. Mechanically, coptisine promotes the Nrf2/HO-1 pathway. CONCLUSION: Coptisine can inhibit the excessive growth, inflammation as well as FMT of lung fibroblasts into myofibroblasts. It could serve as a promising drug of PF.
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Berberina , Proliferação de Células , Fibroblastos , Pulmão , Miofibroblastos , Humanos , Proliferação de Células/efeitos dos fármacos , Berberina/farmacologia , Berberina/análogos & derivados , Miofibroblastos/efeitos dos fármacos , Pulmão/patologia , Pulmão/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Inflamação/tratamento farmacológico , Fator 2 Relacionado a NF-E2/metabolismo , Fibrose Pulmonar/tratamento farmacológico , Fator de Crescimento Transformador beta1/metabolismo , Linhagem Celular , Coptis , Heme Oxigenase-1/metabolismo , Transdução de Sinais/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Diferenciação Celular/efeitos dos fármacos , Anti-Inflamatórios/farmacologiaRESUMO
Smart textiles capable of both energy harvesting and multifunctional sensing are highly desirable for next-generation portable electronics. However, there are still challenges that need to be conquered, such as the innovation of an energy-harvesting model and the optimization of interface bonding between fibers and active materials. Herein, inspired by the spiral structure of natural vines, a highly stretchable triboelectric helical yarn (TEHY) was manufactured by twisting the carbon nanotube/polyurethane nanofiber (CNT/PU NF) Janus membrane. The TEHY had a zebra-stripe-like design that was composed of black interval conductive CNTs and white insulative PU NFs. Due to the different electron affinity, the zebra-patterned TEHY realized a self-frictional triboelectric effect because the numerous microscopic CNT/PU triboelectric interfaces generated an alternating current in the external conductive circuit without extra external friction layers. The helical geometry combined with the elastic PU matrix endowed TEHY with superelastic stretchability and outstanding output stability after 1000 cycles of the stretch-release test. By virtue of the robust mechanical and electrical stability, the TEHY can not only be used as a high-entropy mechanical energy harvester but also serve as a self-powered sensor to monitor the stretching or deforming stimuli and human physiological activities in real time. These merits manifested the versatile applications of TEHY in smart fabrics, wearable power supplies, and human-machine interactions.
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Many biological surfaces are capable of transporting liquids in a directional manner without energy consumption. Inspired by nature, constructing asymmetric gradient surfaces to achieve desired droplet transport, such as a liquid diode, brings an incredibly valuable and promising area of research with a wide range of applications. Enabled by advances in nanotechnology and manufacturing techniques, biomimetics has emerged as a promising avenue for engineering various types of anisotropic material system. Over the past few decades, this approach has yielded significant progress in both fundamental understanding and practical applications. Theoretical studies revealed that the heterogeneous composition and topography mainly govern the wetting mechanisms and dynamics behavior of droplets, including the interdisciplinary aspects of materials, chemistry, and physics. In this review, we provide a concise overview of various biological surfaces that exhibit anisotropic droplet transport. We discussed the theoretical foundations and mechanisms of droplet motion on designed surfaces and reviewed recent research advances in droplet directional transport on designed plane surfaces and Janus membranes. Such liquid-diode materials yield diverse promising applications, involving droplet collection, liquid separation and delivery, functional textiles, and biomedical applications. We also discuss the recent challenges and ongoing approaches to enhance the functionality and application performance of anisotropic materials.
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Pseudotyped viruses have been constructed for many viruses. They can mimic the authentic virus and have many advantages compared to authentic viruses. Thus, they have been widely used as a surrogate of authentic virus for viral function analysis, detection of neutralizing antibodies, screening viral entry inhibitors, and others. This chapter reviewed the progress in the field of pseudotyped viruses in general, including the definition and the advantages of pseudotyped viruses, their potential usage, different strategies or vectors used for the construction of pseudotyped viruses, and factors that affect the construction of pseudotyped viruses.
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Proteínas do Envelope Viral , Pseudotipagem Viral , Proteínas do Envelope Viral/genética , Anticorpos Neutralizantes , Internalização do Vírus , Vetores Genéticos/genéticaRESUMO
It is highly desired but challenging to design high performance catalyst for selective hydrogenation of nitro compounds into amino compounds. Herein, a boosting chemoselective hydrogenation strategy on Pt@Fe2 O3 is proposed with gradient oxygen vacancy by synergy of hydrogen spillover and preferential adsorption. Experimental and theoretical investigations reveal that the nitro is preferentially adsorbed onto oxygen vacancy of Pt@Fe2 O3 , meanwhile, the H2 dissociated on Pt nanoparticles and then spillover to approach the nitro for selective hydrogenation (>99% conversion of 4-nitrostyrene, > 99% selectivity of 4-aminostyrene, TOF of 2351 h-1 ). Moreover, the iron oxide support endows the catalyst magnetic retrievability. This high activity, selectivity, and easy recovery strategy provide a promising avenue for selective hydrogenation catalysis of various nitroaromatic.
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BACKGROUND: Influenza A (H3N2) virus (A/H3N2) has complex antigenic evolution, resulting in frequent vaccine strain updates. We aimed to evaluate the protective effect of the vaccine strains on the circulating strains from past ten years and provide a basis for finding a broader and more efficient A/H3N2 vaccine strain. METHODS: Eighty-four representative circulating A/H3N2 strains were selected from 65,791 deposited sequences in 2011-2020 and pseudotyped viruses were constructed with the VSV vector. We immunized guinea pigs with DNA vaccine containing the A/H3N2 components of the vaccine strains from 2011 to 2021 and tested neutralizing antibody against the pseudotyped viruses. We used a hierarchical clustering method to classify the eighty-four representative strains into different antigenic clusters. We also immunized animals with monovalent vaccine stock of the vaccine strains for the 2020-2021 and 2021-2022 seasons and tested neutralizing antibody against the pseudotyped viruses. FINDINGS: The vaccine strains PE/09, VI/11 and TE/12 induced higher levels of neutralizing antibody against representative strains circulating in recommended year and the year immediately prior whereas vaccine strains HK/14, HK/19 and CA/20 induced poor neutralization against all representative strains. The representative strains were divided into five antigenic clusters (AgV), which were not identical to gene clades. The AgV5 strains were most difficult to be protected among the five clusters. Compared with single-dose immunization, three doses of monovalent vaccine stock (HK/19 or CA/20) could induce stronger and broader neutralizing antibodies against strains in each of the antigenic clusters. INTERPRETATION: The protective effect of vaccine strains indicated that the accurate selection of A/H3N2 vaccine strains must remain a top priority. By increasing the frequency of immunization, stronger and broader neutralizing antibodies against strains in all antigenic clusters were induced, which provides direction for a new immunization strategy. FUNDING: This work was supported by a grant from National Key R&D Program of China (No. 2021YFC2301700).
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Vacinas contra Influenza , Influenza Humana , Cobaias , Animais , Humanos , Vírus da Influenza A Subtipo H3N2/genética , Estações do Ano , Testes de Inibição da Hemaglutinação , Estudos Retrospectivos , Anticorpos Neutralizantes , Anticorpos AntiviraisRESUMO
A steep rise in Omicron reinfection cases suggests that this variant has increased immune evasion ability. To evaluate its antigenicity relationship with other variants, antisera from guinea pigs immunized with spike protein of SARS-CoV-2 variants of concern (VOCs) and variants of interest (VOIs) were cross-tested against pseudotyped variants. The neutralization activity against Omicron was markedly reduced when other VOCs or VOIs were used as immunogens, and Omicron (BA.1)-elicited sera did not efficiently neutralize the other variants. However, a Beta or Omicron booster, when administered as the 4th dose 3-months after the 3rd dose of any of the variants, could elicit broad neutralizing antibodies against all of the current variants including Omicron BA.1. Further analysis with 280 available antigen-antibody structures and quantification of immune escape from 715 reported neutralizing antibodies provide explanations for the observed differential immunogenicity. Three distinct clades predicted using an in silico algorithm for clustering of sarbecoviruses based on immune escape provide key information for rational design of vaccines.
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COVID-19 , SARS-CoV-2 , Animais , Anticorpos Antivirais/genética , COVID-19/genética , Análise por Conglomerados , Cobaias , Humanos , Glicoproteínas de Membrana , Testes de Neutralização , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/genética , Proteínas do Envelope ViralRESUMO
TiO2/g-C3N4 composite photocatalysts with various merits, including low-cost, non-toxic, and environment friendliness, have potential application for producing clean energy and removing organic pollutants to deal with the global energy shortage and environmental contamination. Coating a continuous g-C3N4 layer on TiO2 fibers to form a core/shell structure that could improve the separation and transit efficiency of photo-induced carriers in photocatalytic reactions is still a challenge. In this work, porous TiO2 (P-TiO2)@g-C3N4 fibers were prepared by a hard template-assisted electrospinning method together with the g-C3N4 precursor in an immersing and calcination process. The continuous g-C3N4 layer was fully packed around the P-TiO2 fibers tightly to form a TiO2@g-C3N4 core/shell composite with a strong TiO2/g-C3N4 heterojunction, which greatly enhanced the separation efficiency of photo-induced electrons and holes. Moreover, the great length-diameter ratio configuration of the fiber catalyst was favorable for the recycling of the catalyst. The P-TiO2@g-C3N4 core/shell composite exhibited a significantly enhanced photocatalytic performance both in H2 generation and dye degradation reactions under visible light irradiation, owing to the specific P-TiO2@g-C3N4 core/shell structure and the high-quality TiO2/g-C3N4 heterojunction in the photocatalyst. This work offers a promising strategy to produce photocatalysts with high efficiency in visible light through a rational structure design.
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SARS-CoV-2 has caused the COVID-19 pandemic. B.1.617 variants (including Kappa and Delta) have been transmitted rapidly in India. The transmissibility, pathogenicity, and neutralization characteristics of these variants have received considerable interest. In this study, 22 pseudotyped viruses were constructed for B.1.617 variants and their corresponding single amino acid mutations. B.1.617 variants did not exhibit significant enhanced infectivity in human cells, but mutations T478K and E484Q in the receptor binding domain led to enhanced infectivity in mouse ACE2-overexpressing cells. Furin activities were slightly increased against B.1.617 variants and cell-cell fusion after infection of B.1.617 variants were enhanced. Furthermore, B.1.617 variants escaped neutralization by several mAbs, mainly because of mutations L452R, T478K, and E484Q in the receptor binding domain. The neutralization activities of sera from convalescent patients, inactivated vaccine-immunized volunteers, adenovirus vaccine-immunized volunteers, and SARS-CoV-2 immunized animals against pseudotyped B.1.617 variants were reduced by approximately twofold, compared with the D614G variant.
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COVID-19 , SARS-CoV-2 , Animais , Anticorpos Neutralizantes , Fusão Celular , Humanos , Camundongos , Mutação , Pandemias , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus , Tropismo ViralRESUMO
Both sweat drainage and evaporation play important roles in achieving personal moisture and thermal management during sweat-producing exercises. However, it remains a great challenge to simultaneously realize thermal management through radiative cooling for human body without perspiration. Herein, we report a bilayer nanoporous polyethylene membrane with anisotropic wettability, which possesses superior radiative cooling ability (â¼2.6 °C lower than that of cotton) without perspiration. Meanwhile, it realizes efficient sweat drainage and good evaporation cooling property (â¼1.0 °C lower than that of cotton) in perspiration to avoid sticky and hot sensation. In addition, it can also block water and fine particulate matter owing to the hydrophobic nanoporous structure. By virtue of the outstanding personal thermal and moisture management performance, it is expected that this study provides inspiration for designing new clothing and medical protective suits with more comfortable microclimates and reducing energy consumption for global sustainability.
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Emerging SARS-CoV-2 variants are the most serious problem for COVID-19 prophylaxis and treatment. To determine whether the SARS-CoV-2 vaccine strain should be updated following variant emergence like seasonal flu vaccine, the changed degree on antigenicity of SARS-CoV-2 variants and H3N2 flu vaccine strains was compared. The neutralization activities of Alpha, Beta and Gamma variants' spike protein-immunized sera were analysed against the eight current epidemic variants and 20 possible variants combining the top 10 prevalent RBD mutations based on the Delta variant, which were constructed using pseudotyped viruses. Meanwhile, the neutralization activities of convalescent sera and current inactivated and recombinant protein vaccine-elicited sera were also examined against all possible Delta variants. Eight HA protein-expressing DNAs elicited-animal sera were also tested against eight pseudotyped viruses of H3N2 flu vaccine strains from 2011-2019. Our results indicate that the antigenicity changes of possible Delta variants were mostly within four folds, whereas the antigenicity changes among different H3N2 vaccine strains were approximately 10-100-fold. Structural analysis of the antigenic characterization of the SARS-CoV-2 and H3N2 mutations supports the neutralization results. This study indicates that the antigenicity changes of the current SARS-CoV-2 may not be sufficient to require replacement of the current vaccine strain.
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Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/metabolismo , Vacinas contra COVID-19/metabolismo , COVID-19/prevenção & controle , Imunogenicidade da Vacina , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Substituição de Aminoácidos , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/genética , Anticorpos Antivirais/química , Anticorpos Antivirais/genética , Sítios de Ligação , COVID-19/imunologia , COVID-19/virologia , Vacinas contra COVID-19/administração & dosagem , Vacinas contra COVID-19/química , Epitopos/química , Epitopos/genética , Epitopos/imunologia , Expressão Gênica , Humanos , Soros Imunes/química , Vírus da Influenza A Subtipo H3N2/química , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/química , Vacinas contra Influenza/metabolismo , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Modelos Moleculares , Mutação , Testes de Neutralização , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , SARS-CoV-2/química , SARS-CoV-2/patogenicidade , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Pseudotipagem ViralRESUMO
Variants of SARS-CoV-2 continue to emerge, posing great challenges in outbreak prevention and control. It is important to understand in advance the impact of possible variants of concern (VOCs) on infectivity and antigenicity. Here, we constructed one or more of the 15 high-frequency naturally occurring amino acid changes in the receptor-binding domain (RBD) of Alpha, Beta, and Gamma variants. A single mutant of A520S, V367F, and S494P in the above three VOCs enhanced infectivity in ACE2-overexpressing 293T cells of different species, LLC-MK2 and Vero cells. Aggregation of multiple RBD mutations significantly reduces the infectivity of the possible three VOCs. Regarding neutralization, it is noteworthy that E484K, N501Y, K417N, and N439K predispose to monoclonal antibodies (mAbs) protection failure in the 15 high-frequency mutations. Most importantly, almost all possible VOCs (single RBD mutation or aggregation of multiple mutations) showed no more than a fourfold decrease in neutralizing activity with convalescent sera, vaccine sera, and immune sera of guinea pigs with different immunogens, and no significant antigenic drift was formed. In conclusion, our pseudovirus results could reduce the concern that the aggregation of multiple high-frequency mutations in the RBD of the spike protein of the three VOCs would lead to severe antigenic drift, and this would provide value for vaccine development strategies.
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COVID-19 , SARS-CoV-2 , Animais , Anticorpos Neutralizantes , Deriva e Deslocamento Antigênicos , COVID-19/terapia , Chlorocebus aethiops , Cobaias , Humanos , Imunização Passiva , Mutação , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus , Células Vero , Soroterapia para COVID-19RESUMO
The ubiquitously-expressed proteolytic enzyme furin is closely related to the pathogenesis of SARS-CoV-2 and therefore represents a key target for antiviral therapy. Based on bioinformatic analysis and pseudovirus tests, we discovered a second functional furin site located in the spike protein. Furin still increased the infectivity of mutated SARS-CoV-2 pseudovirus in 293T-ACE2 cells when the canonical polybasic cleavage site (682-686) was deleted. However, K814A mutation eliminated the enhancing effect of furin on virus infection. Furin inhibitor prevented infection by 682-686-deleted SARS-CoV-2 in 293T-ACE2-furin cells, but not the K814A mutant. K814A mutation did not affect the activity of TMPRSS2 and cathepsin L but did impact the cleavage of S2 into S2' and cell-cell fusion. Additionally, we showed that this functional furin site exists in RaTG13 from bat and PCoV-GD/GX from pangolin. Therefore, we discovered a new functional furin site that is pivotal in promoting SARS-CoV-2 infection.
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Enzima de Conversão de Angiotensina 2/metabolismo , Catepsina L/metabolismo , Furina/metabolismo , SARS-CoV-2/genética , Serina Endopeptidases/metabolismo , Glicoproteína da Espícula de Coronavírus/genética , Sequência de Aminoácidos , Enzima de Conversão de Angiotensina 2/genética , Animais , Catepsina L/genética , Fusão Celular , Quirópteros , Furina/genética , Expressão Gênica , Células HEK293 , Humanos , Camundongos , Camundongos Transgênicos , Mutação , Receptores Virais/genética , Receptores Virais/metabolismo , SARS-CoV-2/crescimento & desenvolvimento , SARS-CoV-2/metabolismo , SARS-CoV-2/patogenicidade , Serina Endopeptidases/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , VermilinguaRESUMO
Owing to the low cost, high energy density, and high theoretical specific capacity, lithium-sulfur batteries have been deemed as a potential choice for future energy storage devices. However, they also have suffered from several scientific and technical issues including low conductivity, polysulfides migration, and volume changes. In this study, CoS2-TiO2@carbon core-shell fibers were fabricated through combination of coaxial electrospinning and selective vulcanization method. The core-shell fibers are able to efficiently host sulfur, confine polysulfides, and accelerate intermediates conversion. This electrode delivers an initial specific capacity of 1181.1 mAh g-1 and a high capacity of 736.5 mAh g-1 after 300 cycles with high coulombic efficiency over 99.5% (capacity decay of 0.06% per cycle). This strategy of isolating interactant and selective vulcanization provides new ideas for effectively constructing heterostructure materials for lithium-sulfur batteries.
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Emerging mutations in SARS-CoV-2 cause several waves of COVID-19 pandemic. Here we investigate the infectivity and antigenicity of ten emerging SARS-CoV-2 variants-B.1.1.298, B.1.1.7(Alpha), B.1.351(Beta), P.1(Gamma), P.2(Zeta), B.1.429(Epsilon), B.1.525(Eta), B.1.526-1(Iota), B.1.526-2(Iota), B.1.1.318-and seven corresponding single amino acid mutations in the receptor-binding domain using SARS-CoV-2 pseudovirus. The results indicate that the pseudovirus of most of the SARS-CoV-2 variants (except B.1.1.298) display slightly increased infectivity in human and monkey cell lines, especially B.1.351, B.1.525 and B.1.526 in Calu-3 cells. The K417N/T, N501Y, or E484K-carrying variants exhibit significantly increased abilities to infect mouse ACE2-overexpressing cells. The activities of furin, TMPRSS2, and cathepsin L are increased against most of the variants. RBD amino acid mutations comprising K417T/N, L452R, Y453F, S477N, E484K, and N501Y cause significant immune escape from 11 of 13 monoclonal antibodies. However, the resistance to neutralization by convalescent serum or vaccines elicited serum is mainly caused by the E484K mutation. The convalescent serum from B.1.1.7- and B.1.351-infected patients neutralized the variants themselves better than other SARS-CoV-2 variants. Our study provides insights regarding therapeutic antibodies and vaccines, and highlights the importance of E484K mutation.
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COVID-19/virologia , SARS-CoV-2/genética , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/genética , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/genética , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , COVID-19/terapia , Linhagem Celular , Células HEK293 , Humanos , Imunização Passiva/métodos , Mamíferos/imunologia , Camundongos , Mutação , Pandemias , Primatas/imunologia , Ligação Proteica , Tropismo/genética , Soroterapia para COVID-19RESUMO
With the aid of the confined conversion of layered silicate RUB-15, homogeneously dispersed Au and SnO2 nanoparticles (NPs) were generated in the confined layer space of RUB-15. The Au-SnO2/SiO2 composite was obtained with the structure that ultrafine Au and SnO2 NPs were supported on SiO2 lamellas. Benefited by the Sn(II)-assisted in situ reduction strategy, Au NPs were highly uniformed and evenly distributed in/on the RUB-15. This Au-SnO2/SiO2 composite was employed as a catalyst to the reduction of 4-nitrophenol showing excellent catalytic activity. The catalytic rate constant at room temperature was calculated to be 6.64 min-1, which was dramatically higher than that of Au/SiO2 composite produced by reduction with hydrazine hydrate on the same support of layered silicate RUB-15. The interaction between Au and SnO2 NPs increased the electron density around Au NPs, which was demonstrated to be an essential factor to the excellent catalytic activity of the Au-SnO2/SiO2 composite. The simple and universal synthesis method afforded precise control over the size/spatial arrangement of Au and SnO2 NPs on SiO2 lamellas. The high activity of the Au-SnO2/SiO2 composite demonstrated that the strategy used in this study has good potential application prospect. Furthermore, this work provided new perspective on the catalysis mechanism to the metal/semiconductor synergistic catalyst system.
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The rapid response movement caused by the Marangoni effect, a surface tension gradient-induced mass transfer behavior, has spurred considerable promise for diverse applications from microrobots and microreactors to smart drug delivery. Herein, we fabricated an aligned hollow fiber swimmer that showed self-propel movement on a water surface based on the Marangoni effect. By rational designing of an aligned hollow microstructure and an optimized geometrical shape, this swimmer can move continuously for more than 600 s and the maximum angular velocity can reach 22 rad·s-1. The movement process of the swimmer is clearly monitored by infrared imaging and the process fluid migration. Moreover, this swimmer exhibited a highly controllable motion mode induced by a magnetic field and a concentration gradient. We designed a novel continuous motion system under the heat conversion from solar energy illumination into mechanical energy. This swimmer shows potential application prospects in controlled cargo transportation and convenient energy conversion systems.
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Oil or chemical purification is significant not only for industrial safety production but also because it conforms to the principle of sustainable development. In this paper, based on the synergistic concept of superwettability and nanopores sieve effect, a superoleophilic and under-oil superhydrophobic carbon nanotube/poly(vinylidene fluoride-co-hexafluoropropylene) nanofiber composite membrane is prepared via electrospinning, pressure-driven filtration, and chemical vapor modification. The as-prepared membrane with durable mechanical and chemical stabilities achieves separation efficiency higher than 99.9% and high flux up to 632.5 L m-2 h-1 bar-1 for different water-in-oil emulsions. This membrane is highly promising for the petroleum and chemical industries for both product quality improvement and green recycling manufacturing processes.
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Fluorocarbonos/química , Nanofibras/química , Nanotubos de Carbono/química , Polivinil/química , Emulsões/química , Emulsões/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Propriedades de Superfície , MolhabilidadeRESUMO
Multi-wall Sn/SnO2 @carbon hollow nanofibers evolved from SnO2 nanofibers are designed and programable synthesized by electrospinning, polypyrrole coating, and annealing reduction. The synthesized hollow nanofibers have a special wire-in-double-wall-tube structure with larger specific surface area and abundant inner spaces, which can provide effective contacting area of electrolyte with electrode materials and more active sites for redox reaction. It shows excellent cycling stability by virtue of effectively alleviating pulverization of tin-based electrode materials caused by volume expansion. Even after 2000 cycles, the wire-in-double-wall-tube Sn/SnO2 @carbon nanofibers exhibit a high specific capacity of 986.3â mAh g-1 (1â A g-1 ) and still maintains 508.2â mAh g-1 at high current density of 5â A g-1 . This outstanding electrochemical performance suggests the multi-wall Sn/SnO2 @ carbon hollow nanofibers are great promising for high performance energy storage systems.
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One-dimensional (1D) hollow nanomaterials were widely used in the catalysis field. However, the inner surfaces of 1D hollow nanostructures could not be effectively utilized in liquid reaction because of diffusional limitation caused by the large ratio of length to diameter. In this work, a template-assisted coaxial electrospinning method was developed to prepare TiO2 hollow nanofibers with through-holes which were further employed as a carrier for Au nanoparticles. The Au/TiO2 hollow nanofibers with through-holes showed significant catalytic activity enhancement to the reduction of 4-nitrophenol in aqueous solution compared with solid and hollow nanofiber counterparts. The through-holes which provided unrestricted macropores for mass transfer in liquid solution were studied to be accounted for the catalytic activity enhancement. The through-hole structures can widen the application ranges and increase the efficiencies of zero-dimensional or 1D hollow nanomaterials.