132 research outputs found

    Compact Ag@fe3o4 Core-shell Nanoparticles By Means Of Single-step Thermal Decomposition Reaction.

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    A temperature pause introduced in a simple single-step thermal decomposition of iron, with the presence of silver seeds formed in the same reaction mixture, gives rise to novel compact heterostructures: brick-like Ag@Fe3O4 core-shell nanoparticles. This novel method is relatively easy to implement, and could contribute to overcome the challenge of obtaining a multifunctional heteroparticle in which a noble metal is surrounded by magnetite. Structural analyses of the samples show 4 nm silver nanoparticles wrapped within compact cubic external structures of Fe oxide, with curious rectangular shape. The magnetic properties indicate a near superparamagnetic like behavior with a weak hysteresis at room temperature. The value of the anisotropy involved makes these particles candidates to potential applications in nanomedicine.4683

    Formation Mechanism of Maghemite Nanoflowers Synthesized by a Polyol-Mediated Process

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    Magnetic nanoparticles are being developed as structural and functional materials for use in diverse areas, including biomedical applications. Here, we report the synthesis of maghemite (γ-Fe<sub>2</sub>O<sub>3</sub>) nanoparticles with distinct morphologies: single-core and multicore, including hollow spheres and nanoflowers, prepared by the polyol process. We have used sodium acetate to control the nucleation and assembly process to obtain the different particle morphologies. Moreover, from samples obtained at different time steps during the synthesis, we have elucidated the formation mechanism of the nanoflowers: the initial phases of the reaction present a lepidocrocite (γ-FeOOH) structure, which suffers a fast dehydroxylation, transforming to an intermediate “undescribed” phase, possibly a partly dehydroxylated lepidocrocite, which after some incubation time evolves to maghemite nanoflowers. Once the nanoflowers have been formed, a crystallization process takes place, where the γ-Fe<sub>2</sub>O<sub>3</sub> crystallites within the nanoflowers grow in size (from ∼11 to 23 nm), but the particle size of the flower remains essentially unchanged (∼60 nm). Samples with different morphologies were coated with citric acid and their heating capacity in an alternating magnetic field was evaluated. We observe that nanoflowers with large cores (23 nm, controlled by annealing) densely packed (tuned by low NaAc concentration) offer 5 times enhanced heating capacity compared to that of the nanoflowers with smaller core sizes (15 nm), 4 times enhanced heating effect compared to that of the hollow spheres, and 1.5 times enhanced heating effect compared to that of single-core nanoparticles (36 nm) used in this work

    Compartimentação fisiográfica do município de Peruíbe, litoral de São Paulo - uma abordagem metodológica como subsídio à avaliação geotécnica de terrenos

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    This paper presents a method applied to the seacoast town of Peruibe, São Paulo State, Brazil. The method encompasses the application of remote sensing interpretation techniques and field survey to obtain geotechnical data and thus generate cartographic products composed of easily grouped units that work as database objects and can de used to assist geotechnical zoning. The so-called Compartmentalization Basic Units (CBUs) show the smallest land surface analyzed from its physiographic elements and have in their cores the same geotechnical properties, making it easier to analyze the potentialities and the fragilities of the physical environment and its susceptibility to the action of natural and anthropic processes. In the study area, sixty-eight units were individualized in which geotechnical properties were inferred by photo interpretation criteria, using textural properties of the image adjusted with field observations. The method proved to be easily reproducible, and is especially useful in regions where the absence of basic maps makes it impossible to establish homogeneous zones through traditional overlay of different topic informations.Este artigo apresenta o método empregado no município litorâneo de Peruíbe, composto pela aplicação de técnicas de interpretação de produtos de sensoriamento e levantamentos de campo para a individualização de unidades básicas de análise do terreno, denominadas de Unidades Básicas de Compartimentação (UBCs). Estas unidades expressam a menor superfície do terreno interpretada a partir dos seus elementos fisiográficos, e que possuem no seu interior as mesmas propriedades geotécnicas. São unidades facilmente agrupáveis e funcionam como objetos de armazenamento de informações, que podem subsidiar os zoneamentos geotécnicos, facilitando a análise das potencialidades e fragilidades do meio físico e de sua suscetibilidade a processos naturais e antrópicos. Foram individualizadas sessenta e oito unidades dentro das quais foram inferidas propriedades de interesse geotécnico a partir de critérios fotointerpretativos, levando em consideração as propriedades texturais da imagem, calibradas por observações de campo. O método mostrou-se facilmente reprodutível, sendo especialmente interessante para regiões com carência de mapas básicos, o que impossibilita o estabelecimento de zonas homogêneas através do tradicional cruzamento de informações de diferentes temas

    PHYSIOGRAPHIC COMPARTMENTALIZATION OF PERUIBE MUNICIPALITY, SÃO PAULO STATE COAST - A METHODOLOGICAL APPROACH TO ASSIST GEOTECHNICAL TERRAIN EVALUATION

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    Este artigo apresenta o método empregado no município litorâneo de Peruíbe, composto pela aplicação de técnicas de interpretação de produtos de sensoriamento e levantamentos de campo para a individualização de unidades básicas de análise do terreno, denominadas de Unidades Básicas de Compartimentação (UBCs). Estas unidades expressam a menor superfície do terreno interpretada a partir dos seus elementos fisiográficos, e que possuem no seu interior as mesmas propriedades geotécnicas. São unidades facilmente agrupáveis e funcionam como objetos de armazenamento de informações, que podem subsidiar os zoneamentos geotécnicos, facilitando a análise das potencialidades e fragilidades do meio físico e de sua suscetibilidade a processos naturais e antrópicos. Foram individualizadas sessenta e oito unidades dentro das quais foram inferidas propriedades de interesse geotécnico a partir de critérios fotointerpretativos, levando em consideração as propriedades texturais da imagem, calibradas por observações de campo. O método mostrou-se facilmente reprodutível, sendo especialmente interessante para regiões com carência de mapas básicos, o que impossibilita o estabelecimento de zonas homogêneas através do tradicional cruzamento de informações de diferentes temas.This paper presents a method applied to the seacoast town of Peruibe, São Paulo State, Brazil. The method encompasses the application of remote sensing interpretation techniques and field survey to obtain geotechnical data and thus generate cartographic products composed of easily grouped units that work as database objects and can de used to assist geotechnical zoning. The so-called Compartmentalization Basic Units (CBUs) show the smallest land surface analyzed from its physiographic elements and have in their cores the same geotechnical properties, making it easier to analyze the potentialities and the fragilities of the physical environment and its susceptibility to the action of natural and anthropic processes. In the study area, sixty-eight units were individualized in which geotechnical properties were inferred by photo interpretation criteria, using textural properties of the image adjusted with field observations. The method proved to be easily reproducible, and is especially useful in regions where the absence of basic maps makes it impossible to establish homogeneous zones through traditional overlay of different topic informations

    The Basilicata Wealth Fund: Resource Policy and Long-Run Economic Development in Southern Italy

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    This paper contributes to the growing political economy literature of within-country natural resources management, by proposing a new resource policy for the oil-rich southern Italian region of Basilicata. The policy proposal is to establish a (regional) wealth fund in which all the royalty revenues from non-renewable natural resource exploitation in Basilicata would be stored and fully converted into low-risk financial assets. The scope is to give priority to long-run investments as to better exploit revenues from large-scale extraction of natural capital. Establishing a wealth fund at the regional sub-national level is a novel approach that can be applied to other resource-rich regions in the world. I label the fund as the Basilicata Wealth Fund (BWF). The BWF would be a regionally owned investment fund, however independently administered from national authorities (for instance, as an independent legal entity under the jurisdiction of the Bank of Italy). In addition, the paper posits a transparent and clear-cut spending fiscal rule in order to let regional authorities use the resource revenues to finance economic policy. The clear advantage from the BWF would be the stronger focus on long-run economic development and the higher accountability, hence avoiding misuse of resource revenues for myopic fiscal spending

    Cytotoxic drugs for patients with breast cancer in the era of targeted treatment: Back to the future?

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    Background: Despite current trend of targeted therapy development, cytotoxic agents are a mainstay of treatment of patients with breast cancer. We reviewed recent advances in cytotoxic therapy for patients with metastatic breast cancer (MBC). Materials and methods: Medline searches were conducted for English language studies using the term =MBC= and 'cytotoxic drugs'. The data search was restricted to the period 2000-2011. Results: Several novel cytotoxic compounds, all microtubule inhibitors, have been approved for clinical use in MBC: (i) nab-paclitaxel, reported to improve tumour response and decrease hypersensitivity reactions in comparison with other taxanes; (ii) ixabepilone, shown to have clinical benefit in taxane- and anthracycline-resistant disease and (iii) eribulin, shown to improve overall survival in heavily pre-treated patients, when compared with best available standard treatment. Agents, such as larotaxel, vinflunine, trabectidin and formulations, including cationic liposomal paclitaxel or paclitaxel poliglumex, are currently under evaluation in phase II/III trials. Conclusion: Toxicity and chemotherapy resistance are still major limitations in the treatment of patients with MBC. Further research into new cytotoxic compounds is needed in order to maximise benefit, whilst minimising toxicity

    Desempenho de Cultivares de Soja Transgênica (Intacta e Rr1) na Macrorregião Sojícola 1, Avaliadas na Safra 2013/14 ela Rede Soja Sul de Pesquisa.

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    A Rede Soja Sul de Pesquisa, composta por empresas de melhoramento e de pesquisa (CCGL Tecnologia, Coodetec, GDM Genética do Brasil, Embrapa Clima Temperado, Embrapa Trigo, Fepagro, Geneze Sementes, Nidera Sementes, Syngenta Seeds, TMG, Instituto Federal de Sertão e Fundação Pró-Sementes), conduz ensaios que avaliam, no mesmo ambiente e manejo, o desempenho agronômico de cultivares registradas por diferentes obtentores. Assim, o objetivo deste trabalho foi avaliar o rendimento de grãos de cultivares de soja das tecnologias Intacta e RR1, em ambientes da Macrorregião sojícola 1
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