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Nanoengineering polar oxide films have attracted great attention in energy storage due to their high energy density. However, most of them are deposited on thick and rigid substrates, which is not conducive to the integration of capacitors and applications in flexible electronics. Here, an alternative strategy using van der Waals epitaxial oxide dielectrics on ultra-thin flexible mica substrates is developed and increased the disorder within the system through high laser flux. The introduction of defects can efficiently weaken or destroy the long-range ferroelectric ordering, ultimately leading to the emergence of a large numbers of weak-coupling regions. Such polarization configuration ensures fast polarization response and significantly improves energy storage characteristics. A flexible BiFeO3-BaTiO3 (BF-BT) capacitor exhibits a total energy density of 43.5 J cm-3 and an efficiency of 66.7% and maintains good energy storage performance over a wide temperature range (20-200 °C) and under large bending deformation (bending radii ≈ 2 mm). This study provides a feasible approach to improve the energy storage characteristics of dielectric oxide films and paves the way for their practical application in high-energy density capacitors.
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The proton-electron coupling effect induces rich spectrums of electronic states in correlated oxides, opening tempting opportunities for exploring novel devices with multifunctions. Here, via modest Pt-aided hydrogen spillover at room temperature, amounts of protons are introduced into SmNiO3-based devices. In situ structural characterizations together with first-principles calculation reveal that the local Mott transition is reversibly driven by migration and redistribution of the predoped protons. The accompanying giant resistance change results in excellent memristive behaviors under ultralow electric fields. Hierarchical tree-like memory states, an instinct displayed in bio-synapses, are further realized in the devices by spatially varying the proton concentration with electric pulses, showing great promise in artificial neural networks for solving intricate problems. Our research demonstrates the direct and effective control of proton evolution using extremely low electric field, offering an alternative pathway for modifying the functionalities of correlated oxides and constructing low-power consumption intelligent devices and neural network circuits.
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Aprendizagem , Micro-Ondas , Hipocampo , Aprendizagem em Labirinto , Memória , Micro-Ondas/efeitos adversosRESUMO
An advanced architecture design of nitrogen-doped TiO2 anchored on nitrogen-doped 3D graphene framework composites (denoted as N-TiO2 /N-3D GFs) have been fabricated by a facile template process and further NH3 treatment. The 3D graphene framework allows the electrolyte to penetrate into the inverse opal structure, and possesses high electronic conductivity. The close contact between the N-TiO2 and the graphene suppresses the growth and aggregation of TiO2 nanoparticles during heating process, leading to decreased Li+ diffusion length. The N-doping in both TiO2 and the graphene matrix could improve the electronic conductivity on the TiO2 particle surface and between adjacent particles. As expected, when used as an anode for Li-ion batteries (LIBs), the N-TiO2 /N-3D GFs composite delivers an excellent reversible capacity of 165â mA h g-1 after 200 cycles at 100â mA g-1 and an outstanding rate capability of 114â mA h g-1 after 1000 cycles at 1â Ag-1 . With rational design, this strategy could be extended to other electrode materials that may hold great promise for the development of high energy storage systems.
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Author: Bimetallic platinum-nickel (Pt-Ni) alloys as oxygen reduction reaction (ORR) electrocatalysts show genuine potential to boost widespread use of low-temperature fuel cells in vehicles by virtue of their high catalytic activity. However, their practical implementation encounters primary challenges in structural and catalytic durability caused by the low formation heat of Pt-Ni alloys. Here, we report nanoporous (NP) (Pt1-xNix)3Al intermetallic nanoparticles as oxygen electroreduction catalyst NP (Pt1-xNix)3Al, which circumvents this problem by making use of the extraordinarily negative formation heats of Pt-Al and Ni-Al bonds. The NP (Pt1-xNix)3Al nanocatalyst, which is mass-produced by alloying/dealloying and mechanical crushing technologies, exhibits specific activity of 3.6 mA cm-2Pt and mass activity of 2.4 A mg-1Pt at 0.90 V as a result of both ligand and compressive strain effects, while strong Ni-Al and Pt-Al bonds ensure their exceptional durability by alleviating evolution of Pt, Ni, and Al components and dissolutions of Ni and Al atoms.
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Hydrogen production through electrochemical process is at the heart of key renewable energy technologies including water splitting and hydrogen fuel cells. Despite tremendous efforts, exploring cheap, efficient and durable electrocatalysts for hydrogen evolution still remains as a great challenge. Here we synthesize a nickel-carbon-based catalyst, from carbonization of metal-organic frameworks, to replace currently best-known platinum-based materials for electrocatalytic hydrogen evolution. This nickel-carbon-based catalyst can be activated to obtain isolated nickel atoms on the graphitic carbon support when applying electrochemical potential, exhibiting highly efficient hydrogen evolution performance with high exchange current density of 1.2 mA cm(-2) and impressive durability. This work may enable new opportunities for designing and tuning properties of electrocatalysts at atomic scale for large-scale water electrolysis.
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OBJECTIVE: To gain a better understanding of gene expression changes in the brain following microwave exposure in mice. This study hopes to reveal mechanisms contributing to microwave-induced learning and memory dysfunction. METHODS: Mice were exposed to whole body 2100 MHz microwaves with specific absorption rates (SARs) of 0.45 W/kg, 1.8 W/kg, and 3.6 W/kg for 1 hour daily for 8 weeks. Differentially expressing genes in the brains were screened using high-density oligonucleotide arrays, with genes showing more significant differences further confirmed by RT-PCR. RESULTS: The gene chip results demonstrated that 41 genes (0.45 W/kg group), 29 genes (1.8 W/kg group), and 219 genes (3.6 W/kg group) were differentially expressed. GO analysis revealed that these differentially expressed genes were primarily involved in metabolic processes, cellular metabolic processes, regulation of biological processes, macromolecular metabolic processes, biosynthetic processes, cellular protein metabolic processes, transport, developmental processes, cellular component organization, etc. KEGG pathway analysis showed that these genes are mainly involved in pathways related to ribosome, Alzheimer's disease, Parkinson's disease, long-term potentiation, Huntington's disease, and Neurotrophin signaling. Construction of a protein interaction network identified several important regulatory genes including synbindin (sbdn), Crystallin (CryaB), PPP1CA, Ywhaq, Psap, Psmb1, Pcbp2, etc., which play important roles in the processes of learning and memorye. CONCLUSION: Long-term, low-level microwave exposure may inhibit learning and memory by affecting protein and energy metabolic processes and signaling pathways relating to neurological functions or diseases.
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Biologia Computacional , Expressão Gênica/efeitos da radiação , Aprendizagem , Memória , Micro-Ondas , Animais , Camundongos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Modifications of local structure at atomic level could precisely and effectively tune the capacity of materials, enabling enhancement in the catalytic activity. Here we modulate the local atomic structure of a classical but inert transition metal oxide, tungsten trioxide, to be an efficient electrocatalyst for hydrogen evolution in acidic water, which has shown promise as an alternative to platinum. Structural analyses and theoretical calculations together indicate that the origin of the enhanced activity could be attributed to the tailored electronic structure by means of the local atomic structure modulations. We anticipate that suitable structure modulations might be applied on other transition metal oxides to meet the optimal thermodynamic and kinetic requirements, which may pave the way to unlock the potential of other promising candidates as cost-effective electrocatalysts for hydrogen evolution in industry.
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AIM: Xiao-Ke-An (XKA) is a traditional Chinese medicine (TCM) formula for the treatment of type 2 diabetes (T2D), and the effective ingredients and their targets as well as the mechanisms of XKA remain to be elucidated. In this study we investigated the therapeutic mechanisms of XKA in the treatment of T2D in mice using a Fangjiomics approach. METHODS: KKAy mice feeding on a high-fat diet were used as models of T2D, and were orally treated with XKA (0.75 or 1.5 g · kg(-1) · d(-1)) for 32 d. Microarray mRNA expression data were obtained from the livers of the mice. Differentially expressed genes (DEGs) were identified by reverse rate analysis and ANOVA analysis. The compounds in XKA were identified by LC-MS analysis or collected from TCM databases. The relationships between the compounds and targets were established by combining the DEGs with information derived from mining literature or herb target databases. Relevant pathways were identified through a Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis using WebGestalt. RESULTS: The compound-target-pathway network based on compounds identified by LC-MS analysis (NCA) included 20 constituent compounds, 46 targets and 36 T2D-related pathways, whereas the compound-target-pathway network based on compounds collected from databases (NCD) consisted of 40 compounds, 68 targets and 21 pathways. In the treatment of T2D, XKA might act mainly by improving carbohydrate and lipid metabolism, as well as ameliorating insulin resistance, inflammation and diabetic vascular complications. CONCLUSION: The network-based approach reveals complex therapeutic mechanisms of XKA in the treatment of T2D in mice that involve numerous compounds, targets, and signaling pathways.
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Diabetes Mellitus Tipo 2/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Genômica/métodos , Hipoglicemiantes/farmacologia , Fígado/efeitos dos fármacos , Medicina Tradicional Chinesa/métodos , Biologia de Sistemas/métodos , Administração Oral , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Cromatografia Líquida , Análise por Conglomerados , Mineração de Dados , Bases de Dados Genéticas , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Dieta Hiperlipídica , Modelos Animais de Doenças , Medicamentos de Ervas Chinesas/administração & dosagem , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Hipoglicemiantes/administração & dosagem , Fígado/metabolismo , Masculino , Espectrometria de Massas , Camundongos Endogâmicos C57BL , Análise de Sequência com Séries de Oligonucleotídeos , Mapas de Interação de Proteínas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais/efeitos dos fármacos , Integração de Sistemas , Fatores de TempoRESUMO
The key factors governing the single-phase or multi-phase structural change behaviors during the intercalation/deintercalation of guest ions have not been well studied and understood yet. Through systematic studies of orthorhombic Fe2(MoO4)3 electrode, two distinct guest ion occupation paths, namely discrete one for Li and pseudo-continuous one for Na, as well as their relationship with single-phase and two-phase modes for Na(+) and Li(+), respectively during the intercalation/deintercalation process have been demonstrated. For the first time, the direct atomic-scale observation of biphasic domains (discrete occupation) in partially lithiated Fe2(MoO4)3 and the one by one Na occupation (pseudo-continuous occupation) at 8d sites in partially sodiated Fe2(MoO4)3 are obtained during the discharge processes of Li/Fe2(MoO4)3 and Na/Fe2(MoO4)3 cells respectively. Our combined experimental and theoretical studies bring the new insights for the research and development of intercalation compounds as electrode materials for secondary batteries.
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Rechargeable magnesium batteries have attracted recent research attention because of abundant raw materials and their relatively low-price and high-safety characteristics. However, the sluggish kinetics of the intercalated Mg(2+) ions in the electrode materials originates from the high polarizing ability of the Mg(2+) ion and hinders its electrochemical properties. Here we report a facile approach to improve the electrochemical energy storage capability of the Li4 Ti5 O12 electrode in a Mg battery system by the synergy between Mg(2+) and Li(+) ions. By tuning the hybrid electrolyte of Mg(2+) and Li(+) ions, both the reversible capacity and the kinetic properties of large Li4 Ti5 O12 nanoparticles attain remarkable improvement.
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Fontes de Energia Elétrica , Técnicas Eletroquímicas , Lítio/química , Magnésio/química , Óxidos/química , Titânio/química , EletrodosRESUMO
OBJECTIVE: To overcome the deficiency in the current therapies for erectile dysfunction (ED), we designed and synthesized a novel high-efficiency polymer/gene compound drug controlled release system and discussed the feasibility of pH and temperature dually sensitive injectable hydrogel in ED gene therapy. METHODS: We synthesized optimal siRNA gene nanoparticles by characterizing the zeta potential of polylysine (PLL)/siRNA gene compounds, and established a pH and temperature dually sensitive injectable gene compound drug controlled release system via Schiffs reaction between glycol chitosan (GC) and benzaldehyde capped OHC-PEO-PPO-PEO-CHO. Then we demonstrated the sustained release of the system at different temperatures. RESULTS: When the mass ratio of PLL to siRNA was 20:1, the zeta potential of the PLL/siRNA gene compound reached the peak (+23.5 mV) and the siRNA was encapsulated by PLL in the maximal degree. GC and OHC-PEO-PPO-PEO-CHO was crosslinked via benzoicimine reaction when environmental pH was changed from 5.5 to 7.4. The reslease of the siRNA encapsulated in this system kept at a low rate at 37 degrees C, significantly enhanced with the increase of the temperature to 60 degrees C, rising to (122.5 +/- 5.3) microg at 1 000 minutes as compared with (23.8 +/- 6.0) microg at 37 degrees C (P < 0.05). CONCLUSION: The polymer/gene compound drug controlled release system was successfully synthesized, which improved the stability and capacity of gene carriers and achieved siRNA release at different temperatures, promising to be a new approach to the gene therapy of ED.
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Preparações de Ação Retardada/farmacologia , Sistemas de Liberação de Medicamentos , Disfunção Erétil/tratamento farmacológico , Terapia Genética , Humanos , Masculino , Nanopartículas/química , Polilisina/química , Polímeros , RNA Interferente Pequeno/farmacologiaRESUMO
Exposure to thermal environment is one of the main concerns for manned space exploration. By focusing on the works performed on thermoregulation at microgravity or simulated microgravity, we endeavored to review the investigation on space thermal environmental physiology. First of all, the application of medical requirements for the crew module design from normal thermal comfort to accidental thermal emergencies in a space craft will be addressed. Then, alterations in the autonomic and behavioral temperature regulation caused by the effect of weightlessness both in space flight and its simulation on the ground are also discussed. Furthermore, countermeasures like exercise training, simulated natural ventilation, encouraged drink, etc., in the protection of thermoregulation during space flight is presented. Finally, the challenge of space thermal environment physiology faced in the future is figured out.
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Medicina Aeroespacial , Regulação da Temperatura Corporal , Voo Espacial , Meio Ambiente , Exercício Físico , Humanos , Ausência de Peso , Simulação de Ausência de PesoRESUMO
OBJECTIVE: To assess the efficacy and safety of percutaneous cryoablation (PCC) and (125)I seed implantation combined with chemotherapy for advanced pancreatic cancer. METHODS: Sixty-seven patients with advanced pancreatic cancer (6 in stage III, 61 in stage IV) received PCC and (125)I seed implantation combined with concomitant gemcitabine hydrochloride and DDP chemotherapy. The clinical benefit response (CBR), survival rate and therapy-related complications were assessed. RESULTS: All patients except one were followed up over 1 year. The 6-month and 1-year survival rates were 84.8% and 33.4%, respectively. The median progression free survival were 6.3 months and 5.5 months in the group stage III and group stage IV (P > 0.05), respectively, while the overall survival was 9.1 months in the group stage III and 11.0 months in the group stage IV (P > 0.05). CR,PR and SD were achieved in 5, 8, 54 patients, respectively. Fifty-four and 50 in the 67 patients experienced a ≥ 50% reduction of pain score and analgesic consumption, respectively, 18 patients experienced a ≥ 2 kg weight gaining, and KPS was increasing from 71.2 ± 0.4 to (90.0 ± 0.3, P < 0.05), the overall benefit rate was 80.6%. No serious therapy-related complications except pancreatic fistula accompanied abdominal hemorrhage, bile leakage, acute pancreatitis and needle track seeding in 1, 1, 2 and 1 case, respectively. CONCLUSION: Percutaneous cryoablation and (125)I seed implantation combined with chemotherapy are effective and safe for the treatment of advanced pancreatic cancer.