318 research outputs found

    Anharmonic transitions in nearly dry L-cysteine I

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    Two special dynamical transitions of universal character have been recently observed in macromolecules at TD180220T_{D}\sim 180 - 220 K and T100T^{*}\sim 100 K. Despite their relevance, a complete understanding of the nature of these transitions and their consequences for the bio-activity of the macromolecule is still lacking. Our results and analysis concerning the temperature dependence of structural, vibrational and thermodynamical properties of the orthorhombic polymorph of the amino acid L-cysteine (at a hydration level of 3.5%) indicated that the two referred temperatures define the triggering of very simple and specific events that govern all the biochemical interactions of the biomolecule: activation of rigid rotors (T<TT<T^{*}), phonon-phonon interactions with phonons of water dimer (T<T<TDT^{*}<T<T_{D}), and water rotational barriers surpassing (T>TDT>T_{D}).Comment: 4 pages, 4 figures, submitted to Physical Review Letter

    Comparison Of Fusobacterium Nucleatum And Porphyromonas Gingivalis Lipopolysaccharides Clinically Isolated From Root Canal Infection In The Induction Of Pro-inflammatory Cytokines Secretion

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    The aim of this study was to compare the biological activity of lipopolysaccharides (LPS) purified from Fusobacterium nucleatum and Porphyromonas gingivalis strains, both isolated from primary endodontic infection (PEI) in the levels of IL-1&#946; and TNF-&#945; released by macrophage cells. Moreover, LPS was purified from F. nucleatum and P. gingivalis American Type Collection (ATCC) and its biological activity was compared to respectively clinical isolates strains. F. nucleatum and P. gingivalis strains clinically isolated from PEI had their identification confirmed by sequencing the 16S rRNA gene. LPS from F. nucleatum and P. gingivalis and their respective ATCC strains were extracted by using Tri-reagent method. Macrophages (Raw 264.7) were stimulated with LPS at 100 ng/mL for 4, 8 and 12 h. Secretion of IL-1 &#946; and TNF-&#945; was also determined. Paired t-test, repeated measures ANOVA and one-way ANOVA were employed. All LPS induced significant production of IL-1&#946; and TNF-&#945;, with the former being secreted at higher levels than the latter in all time-points. F. nucleatum induced a higher expression of both cytokines compared to P. gingivalis (p&lt;0.05). No differences were observed between clinical and ATCC strains, as both presented the same potential to induce pro-inflammatory response. It was concluded that F. nucleatum and P. gingivalis LPS presented different patterns of activation against macrophages as seen by the IL-1&#946; and TNF-&#945; production, which may contribute to the immunopathogenesis of apical periodontitis. Moreover, clinical and ATCC strains grown under the same in vitro environment conditions presented similar biological activity.27220220

    Micro-abrasion wear behaviour of TiAlCrSiN nanostructured coatings

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    The injection process of glass fibres reinforced plastics promotes the moulds surface degradation by erosion. In order to improve its wear resistance, several kinds of PVD thin hard coatings were used. It is well-known that nanostructures present a better compromise between hardness and toughness. Indeed, when the coating is constituted by a large number of ultra-thin different layers, cracks and interface troubles tend to decrease. However, it is not clear that these nanostructures present a better wear behaviour in erosion processes. In order to study its wear behaviour, a sputtered PVD nanostructured TiAlCrSiN coating was used. The substrate and film surfaces topography were analyzed by profilometry and atomic force microscopy techniques. Film adhesion to the substrate was evaluated by scratch tests. The surface hardness was measured with a Vickers micro-hardness tester. The wear resistance was evaluated by micro-abrasion with a rotating ball tribometer tests. Slurry of SiC particles in distilled water was used in order to provoke the surface abrasion. Different duration tests were performed in order to analyze the wear evolution. After these tests, the wear mechanisms developed were analyzed by scanning electron microscopy. Wear craters were measured and the wear rate was calculated and discussed. With the same purpose, coated inserts were mounted in an injection mould working with a 30% glass fibres reinforced polypropylene. After 45 000 cycles no relevant wear was registered

    Influence of the abrasive particles size in the micro-abrasion wear tests of TiAlSiN thin coatings

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    Ball rotating micro-abrasion tribometers are commonly used to carry out wear tests on thin hard coatings. In these tests, different kinds of abrasives were used, as alumina (Al2O3), silicon carbide (SiC) or diamond. In each kind of abrasive, several particle sizes can be used. Some studies were developed in order to evaluate the influence of the abrasive particle shape in the micro-abrasion process. Nevertheless, the particle size was not well correlated with the material removed amount and wear mechanisms. In this work, slurry of SiC abrasive in distilled water was used, with three different particles size. Initial surface topography was accessed by atomic force microscopy (AFM). Coating hardness measurements were performed with a micro-hardness tester. In order to evaluate the wear behaviour, a TiAlSiN thin hard film was used. The micro-abrasion tests were carried out with some different durations. The abrasive effect of the SiC particles was observed by scanning electron microscopy (SEM) both in the films (hard material) as in the substrate (soft material), after coating perforation. Wear grooves and removed material rate were compared and discussed

    Photonic superdiffusive motion in resonance line radiation trapping - partial frequency redistribution effects

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    The relation between the jump length probability distribution function and the spectral line profile in resonance atomic radiation trapping is considered for Partial Frequency Redistribution (PFR) between absorbed and reemitted radiation. The single line Opacity Distribution Function [M.N. Berberan-Santos et.al. J.Chem.Phys. 125, 174308 (2006)] is generalized for PFR and used to discuss several possible redistribution mechanisms (pure Doppler broadening, combined natural and Doppler broadening and combined Doppler, natural and collisional broadening). It is shown that there are two coexisting scales with a different behavior: the small scale is controlled by the intricate PFR details while the large scale is essentially given by the atom rest frame redistribution asymptotic. The pure Doppler and combined natural, Doppler and collisional broadening are characterized by both small and large scale superdiffusive Levy flight behaviors while the combined natural and Doppler case has an anomalous small scale behavior but a diffusive large scale asymptotic. The common practice of assuming complete redistribution in core radiation and frequency coherence in the wings of the spectral distribution is incompatible with the breakdown of superdiffusion in combined natural and Doppler broadening conditions

    Gathering spatial data on social vulnerability in Brazil.

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    The Brazilian Ministry of Agricultural and Social Development coordinates several public policies aimed at minimizing social vulnerabilities by means of several programs. These programs' databases are broadcasted to dedicated teams that manage their data using spreadsheets. The need for an integrated view on the territorial coverage of these data motivated a partnership with Embrapa. This paper aims to present the main results of the quantitative, qualitative and cartographic analyses on this data. The resulting geographic data are available in a web platform that may be used in the decision-making process for the expansion or reorganization of governmental social programs

    Comparison of fusobacterium nucleatum and porphyromonas gingivalis lipopolysaccharides clinically isolated from root canal infection in the induction of pro-inflammatory cytokines secretion

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    The aim of this study was to compare the biological activity of lipopolysaccharides (LPS) purified from Fusobacterium nucleatum and Porphyromonas gingivalis strains, both isolated from primary endodontic infection (PEI) in the levels of IL-1β and TNF-α released by macrophage cells. Moreover, LPS was purified from F. nucleatum and P. gingivalis American Type Collection (ATCC) and its biological activity was compared to respectively clinical isolates strains. F. nucleatum and P. gingivalis strains clinically isolated from PEI had their identification confirmed by sequencing the 16S rRNA gene. LPS from F. nucleatum and P. gingivalis and their respective ATCC strains were extracted by using Tri-reagent method. Macrophages (Raw 264.7) were stimulated with LPS at 100 ng/mL for 4, 8 and 12 h. Secretion of IL-1 β and TNF-α was also determined. Paired t-test, repeated measures ANOVA and one-way ANOVA were employed. All LPS induced significant production of IL-1β and TNF-α, with the former being secreted at higher levels than the latter in all time-points. F. nucleatum induced a higher expression of both cytokines compared to P. gingivalis (p<0.05). No differences were observed between clinical and ATCC strains, as both presented the same potential to induce pro-inflammatory response. It was concluded that F. nucleatum and P. gingivalis LPS presented different patterns of activation against macrophages as seen by the IL-1β and TNF-α production, which may contribute to the immunopathogenesis of apical periodontitis. Moreover, clinical and ATCC strains grown under the same in vitro environment conditions presented similar biological activity272202207CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP302575/2009-0; 150557/2011-6; 308162/2014-510/19136-1; 10/17877- 4; 11/50051-5; 11/50510-0; 11/09047-4O objetivo deste estudo foi comparar a atividade biológica de lipopolissacarídeos (LPS) purificados a partir de linhagens de Fusobacterium nucleatum e Porphyromonas gingivalis, ambas isoladas de infecções endodônticas primárias (IEP) nos níveis de IL-1β e TNF-α produzidos por macrófagos. Adicionalmente, LPS foi purificado de F. nucleatum e P. gingivalis "American Type Collection" (ATCC) e sua atividade comparada às respectivas linhagens clinicamente isoladas. Linhagens de F. nucleatum e P. gingivalis isoladas clinicamente de IEP tiveram sua identificação confirmada por sequenciamento do gene 16S rRNA. LPS de F. nucleatum e P. gingivalis e das respectivas linhagens foram extraídos com o uso do método "Tri-reagent". Macrófagos (Raw 264.7) foram estimulados com LPS a 100 ng/mL por 4, 8 e 12 h. A secreção de IL-1β e de TNF-α foi determinada. Foram usados os testes t-pareado, ANOVA de medidas repetidas e ANOVA de um fator. Todos os LPS induziram a produção significante de IL-1β e TNF-α, sendo o primeiro secretado em mais altas concentrações que o último em todos os tempos avaliados. F. nucleatum induziu uma maior expressão de ambas as citocinas comparativamente ao P. gingivalis (p<0,05). Não foram observadas diferenças entre as linhagens clínica e ATCC, uma vez que ambas apresentaram o mesmo potencial de indução da resposta pró-inflamatória. Conclui-se que F. nucleatum e P. gingivalis possuem diferentes padrões de ativação dos macrófagos, como visto pela produção de IL-1β e TNF-α, o que pode contribuir para a imunopatogênese da periodontite apical. Ainda, linhagens clínica e ATCC mantidas no mesmo ambiente in vitro apresentaram ativação biológica semelhant

    Practical computational toolkits for dendrimers and dendrons structure design

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    Dendrimers and dendrons offer an excellent platform for developing novel drug delivery systems and medicines. The rational design and further development of these repetitively branched systems are restricted by difficulties in scalable synthesis and structural determination, which can be overcome by judicious use of molecular modelling and molecular simulations. A major difficulty to utilise in silico studies to design dendrimers lies in the laborious generation of their structures. Current modelling tools utilise automated assembly of simpler dendrimers or the inefficient manual assembly of monomer precursors to generate more complicated dendrimer structures. Herein we describe two novel graphical user interface (GUI) toolkits written in Python that provide an improved degree of automation for rapid assembly of dendrimers and generation of their 2D and 3D structures. Our first toolkit uses the RDkit library, SMILES nomenclature of monomers and SMARTS reaction nomenclature to generate SMILES and mol files of dendrimers without 3D coordinates. These files are used for simple graphical representations and storing their structures in databases. The second toolkit assembles complex topology dendrimers from monomers to construct 3D dendrimer structures to be used as starting points for simulation using existing and widely available software and force fields. Both tools were validated for ease-of-use to prototype dendrimer structure and the second toolkit was especially relevant for dendrimers of high complexity and size.Peer reviewe

    Qualificação Territorial da Agropecuária e Socioeconomia do Pantanal Brasileiro

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    O Pantanal brasileiro luta para se reinventar na busca pelo desenvolvimento agropecuário sustentável, aliando crescimento econômico com suas condições naturais peculiares e a preservação da sua vegetação natural. Dado seu histórico isolamento territorial causado pela distância dos principais polos nacionais e das dificuldades logísticas, fazem-se necessários estudos que busquem caracterizar a região pantaneira. O objetivo deste trabalho é promover uma discussão sobre o contexto territorial da agropecuária e socioeconomia pantaneira, utilizando ferramentas de geotecnologias para análise e disponibilização dessas informações com referência geográfica O intuito é contribuir na definição de políticas públicas e ações de parcerias público-privadas que resultem em propostas, programas e/ou ações necessárias ou pertinentes para o desenvolvimento sustentável da região

    Apoio ao desenvolvimento agropecuário e social em Alagoas

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    O estado do Alagoas possui 102 municípios agrupados em 13 microrregiões geográficas e distribuídos em 2,7 milhões de hectares. Sua população total é de 3.120.494 habitantes, sendo que aproximadamente 26% residem em áreas rurais (IBGE, 2010). Os 123.332 estabelecimentos agropecuários existentes no estado ocupam quase 76% de sua área total (2.112.567 hectares). Apesar da grande presença, a contribuição da agropecuária para o PIB do estado foi de apenas 6% em 2010. A ocupação territorial da agricultura não reflete sua importância econômica para o estado, especialmente no que tange a agricultura familiar. A análise integrada de aspectos naturais, agrários, agrícolas, de infraestrutura e socioeconômicos é essencial para a compreensão de um território. Condições climáticas desfavoráveis, cenários agrários conflitivos ou deficiências em infraestrutura de armazenamento ou logística contribuem ou impactam substancialmente sobre o desenvolvimento da agricultura de uma região (MIRANDA et al., 2014). Apesar do grande volume de dados espaciais hoje disponíveis na web, a maior parte deles encontra-se dispersa nas várias agências e órgãos públicos geradores de dados. Iniciativas governamentais de agregar esses dados ainda estão em fase de implantação e demandam esforços adicionais para efetiva análise integrada (BRASIL, 2008). Além disso, grande parte 4° GeoAlagoas ? Simpósio sobre as geotecnologias e geoinformação no Estado de Alagoas dos estudos convencionais para o desenvolvimento agropecuário regional é direcionada por cadeia produtiva, o que também dificulta a visão global. O objetivo desse trabalho é prover uma visão integrada do contexto territorial do estado do Alagoas no que tange aspectos de desenvolvimento agropecuário. O intuito é promover uma discussão e elencar informações relevantes para subsidiar políticas públicas e ações público-privadas que resultem em ações pertinentes para o desenvolvimento sustentável do estado. Os produtos da caracterização territorial podem servir a diversos propósitos em função dos interesses das instituições que operam e irão trabalhar na região e até mesmo direcionar ações de transferência de tecnologia.4º GeoAlagoas
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