260 research outputs found

    Incorporation Of Nanocrystals With Different Dimensionalities In Hybrid Tio2/p3ht Solar Cells

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    We investigate the effect of TiO2 nanoparticles-nanospheres and nanorods-inserted in the poly(3-hexylthiophene) (P3HT) matrix of TiO2?P3HT inverted hybrid solar cells. X-ray diffraction, high-resolution transmission electron microscopy, small-angle x-ray scattering, photoluminescence, and photoelectrochemical experiments were employed to investigate the structure, morphology, and photoactivity of TiO2 nanoparticles modified with 2-thiopheneacetic acid, mixed or not with P3HT. Both TiO2 nanospheres and TiO2 nanorods presented a good dispersion in the polymer matrix. The incorporation of TiO2 nanospheres and nanorods has improved the photocurrent generation, and devices with efficiency values up to 1.35% were obtained. Our results reveal that the nanoscale morphology enables an enhanced interfacial area for exciton dissociation. In particular, the nanospheres contribute with their high specific area, and the nanorods contribute with their high aspect ratio.51Lee, C.-K., Pao, C.-W., Chen, C.-W., Correlation of nanoscale organizations of polymer and nanocrystals in polymer/inorganic nanocrystal bulk heterojunction hybrid solar cells: Insights from multiscale molecular simulations (2013) Energy Environ. Sci., 6, pp. 307-315Huynh, W.U., Dittmer, J.J., Alivisatos, A.P., Hybrid nanorod: Polymer solar cells (2002) Science, 295, pp. 2425-2427Sian, S., Chen, C.-W., Polymer-metal-oxide hybrid solar cells (2013) J. Mater. Chem. A, 1, pp. 10574-10591Das, J., A facile nonaqueous route for fabricating titania nanorods and their viability in quasi-solid-state dye-sensitized solar cells (2010) J. Mater. Chem., 20, pp. 4425-4431Cozzoli, P.D., Kornowski, A., Weller, H., Low-temperature synthesis of soluble and processable organic-capped anatase TiO2 nanorods (2003) J. Am. Chem. Soc., 125, pp. 14539-14548Zeng, T.W., A large interconnecting network within hybrid MEH-PPV/TiO2 nanorod photovoltaic devices (2006) Nanotechnology, 17, p. 5387Yang, P., TiO2 nanowire electron transport pathways inside organic photovoltaics (2013) Phys. Chem. Chem. Phys., 15, pp. 4566-4572Lin, Y., Morphology control in TiO2 nanorod/polythiophene composites for bulk heterojunction solar cells using hydrogen bonding (2012) Macromolecules, 45, pp. 8665-8673Ranjitha, A., Inverted organic solar cells based on Cd-doped TiO2 as an electron extraction layer (2014) Superlattices Microstruct., 74, pp. 114-122Bolognesi, M., The effect of selective contact electrodes on the interfacial charge recombination kinetics and device efficiency of organic polymer solar cells (2011) Phys. Chem. Chem. Phys., 13, pp. 6105-6109Mor, G.K., High efficiency double heterojunction polymer photovoltaic cells using highly ordered TiO2 nanotube arrays (2007) Appl. Phys. Lett., 91, p. 152111Planells, M., Oligothiophene interlayer effect on photocurrent generation for hybrid TiO2/P3HT solar cells (2014) Appl. Mater. Interfaces, 6, pp. 17226-17235Freitas, F.S., Tailoring the interface using thiophene small molecules in TiO2/P3HT hybrid solar cells (2012) Phys. Chem. Chem. Phys., 14, pp. 11990-11993Liu, K., Efficient hybrid plasmonic polymer solar cells with Ag nanoparticle decorated TiO2 nanorods embedded in the active layer (2014) Nanoscale, 6, pp. 6180-6186Lin, Y.-Y., Interfacial nanostructuring on the performance of polymer/TiO2 nanorod bulk heterojunction solar cells (2009) J. Am. Chem. Soc., 131, pp. 3644-3649Eom, S.H., Roles of interfacial modifiers in hybrid solar cells: Inorganic/polymer bilayer versus inorganic/polymer: Fullerene bulk heterojunction (2014) Appl. Mater. 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    CURSO DE FORMAÇÃO PEDAGÓGICA PARA MONITORES DA UFAPE: CONTRIBUIÇÕES ACADÊMICAS E PROFISSIONAIS

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    Nesse artigo a partir da experiência vivenciada no projeto de ensino coordenado pela Comissão de Ensino, em parceria com a Coordenação Geral de Cursos de Graduação, da Unidade Acadêmica de Garanhuns (UFRPE), atual Universidade Federal do Agreste de Pernambuco - UFAPE, em 2019, analisam-se as contribuições do curso para formação dos monitores para a formação acadêmica e profissional dos estudantes participantes do evento. Adota como fundamentação teórica os estudos de Lee Shulman que investigam conhecimentos necessários para o ensino. Os dados foram coletados por meio de um formulário on-line composto, em sua maior parte, por perguntas que deveriam ser respondidas atribuindo pontuação de 1 a 5, utilizando a escala de Likert. O perfil dos participantes foi diversificado, incluindo discentes ligados aos programas de monitoria e tutoria bolsistas ou voluntários. As motivações, indicadas pelos discentes participantes do curso, para ingresso nos programas de monitoria ou tutoria estão alinhadas com as definidas na resolução UFRPE 262/2001. Os participantes citaram positivamente a relação dos temas tratados com as atividades práticas da monitoria destacando-se o estímulo à profissão docente, especialmente ao contribuir para o desenvolvimento de conhecimentos pedagógicos, sobre avaliação; aprendizagem; metodologias de ensino, entre outros, importantes aspectos para a profissionalização docente

    Correction of Basic Equations for Deep Bed Filtration with Dispersion

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    Copyright © 2006 Elsevier B.V. All rights reserved.Deep bed filtration of particle suspensions in porous media occurs during water injection into oil reservoirs, drilling fluid invasion into reservoir productive zones, fines migration in oil fields, bacteria, virus or contaminant transport in groundwater, industrial filtering, etc. The basic features of the process are advective and dispersive particle transport and particle capture by the porous medium. Particle transport in porous media is determined by advective flow of carrier water and by hydrodynamic dispersion in micro-heterogeneous media. Thus, the particle flux is the sum of advective and dispersive fluxes. Transport of particles in porous media is described by an advection–diffusion equation and by a kinetic equation of particle capture. Conventional models for deep bed filtration take into account hydrodynamic particle dispersion in the mass balance equation but do not consider the effect of dispersive flux on retention kinetics. In the present study, a model for deep bed filtration with particle size exclusion taking into account particle hydrodynamic dispersion in both mass balance and retention kinetics equations is proposed. Analytical solutions are obtained for flows in infinite and semi-infinite reservoirs and in finite porous columns. The physical interpretation of the steady-state flow regimes described by the proposed and the traditional models favours the former.Altoe, J. E., Bedrikovetski, P.G., Siqueira, A. G., de Souza, A. L., Shecaira, F.http://www.elsevier.com/wps/find/journaldescription.cws_home/503345/description#descriptio

    C9ORF72 patient-derived endothelial cells drive blood-brain barrier disruption and contribute to neurotoxicity

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    The blood-brain barrier (BBB) serves as a highly intricate and dynamic interface connecting the brain and the bloodstream, playing a vital role in maintaining brain homeostasis. BBB dysfunction has been associated with multiple neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS); however, the role of the BBB in neurodegeneration is understudied. We developed an ALS patient-derived model of the BBB by using cells derived from 5 patient donors carrying C9ORF72 mutations. Brain microvascular endothelial-like cells (BMEC-like cells) derived from C9ORF72-ALS patients showed altered gene expression, compromised barrier integrity, and increased P-glycoprotein transporter activity. In addition, mitochondrial metabolic tests demonstrated that C9ORF72-ALS BMECs display a significant decrease in basal glycolysis accompanied by increased basal and ATP-linked respiration. Moreover, our study reveals that C9-ALS derived astrocytes can further affect BMECs function and affect the expression of the glucose transporter Glut-1. Finally, C9ORF72 patient-derived BMECs form leaky barriers through a cell-autonomous mechanism and have neurotoxic properties towards motor neurons
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