238 research outputs found

    Reformulation in mathematical programming: An application to quantum chemistry

    Get PDF
    AbstractThis paper concerns the application of reformulation techniques in mathematical programming to a specific problem arising in quantum chemistry, namely the solution of Hartree–Fock systems of equations, which describe atomic and molecular electronic wave functions based on the minimization of a functional of the energy. Their traditional solution method does not provide a guarantee of global optimality and its output depends on a provided initial starting point. We formulate this problem as a multi-extremal nonconvex polynomial programming problem, and solve it with a spatial Branch-and-Bound algorithm for global optimization. The lower bounds at each node are provided by reformulating the problem in such a way that its convex relaxation is tight. The validity of the proposed approach was established by successfully computing the ground-state of the helium and beryllium atoms

    In Vivo Biodistribution of Respirable Solid Lipid Nanoparticles Surface-Decorated with a Mannose-Based Surfactant: A Promising Tool for Pulmonary Tuberculosis Treatment?

    Get PDF
    The active targeting to alveolar macrophages (AM) is an attractive strategy to improve the therapeutic efficacy of ‘old’ drugs currently used in clinical practice for the treatment of pulmonary tuberculosis. Previous studies highlighted the ability of respirable solid lipid nanoparticle assemblies (SLNas), loaded with rifampicin (RIF) and functionalized with a novel synthesized mannose-based surfactant (MS), both alone and in a blend with sodium taurocholate, to efficiently target the AM via mannose receptor-mediated mechanism. Here, we present the in vivo biodistribution of these mannosylated SLNas, in comparison with the behavior of both non-functionalized SLNas and bare RIF. SLNas biodistribution was assessed, after intratracheal instillation in mice, by whole-body real-time fluorescence imaging in living animals and RIF quantification in excised organs and plasma. Additionally, SLNas cell uptake was determined by using fluorescence microscopy on AM from bronchoalveolar lavage fluid and alveolar epithelium from lung dissections. Finally, histopathological evaluation was performed on lungs 24 h after administration. SLNas functionalized with MS alone generated the highest retention in lungs associated with a poor spreading in extra-pulmonary regions. This effect could be probably due to a greater AM phagocytosis with respect to SLNas devoid of mannose on their surface. The results obtained pointed out the unique ability of the nanoparticle surface decoration to provide a potential more efficient treatment restricted to the lungs where the primary tuberculosis infection is located

    Co-distribution of cysteine cathepsins and matrix metalloproteases in human dentin

    Get PDF
    It has been hypothesized that cysteine cathepsin's (CTs) along with matrix metalloproteases (MMPs) may work in conjunction in the proteolysis of mature dentin matrix. The aim of this study was to verify simultaneously the distribution and presence of cathepsins B (CT-B) and K (CT-K) in partially demineralized dentin; and further to evaluate the activity of CTs and MMPs in the same tissue. The distribution of CT-B and CT-K in sound human dentin was assessed by immunohistochemistry. A double-immunolabeling technique was used to identify, at once, the occurrence of those enzymes in dentin. Activities of CTs and MMPs in dentin extracts were evaluated spectrofluorometrically. In addition, in situ gelatinolytic activity of dentin was assayed by zymography. The results revealed the distribution of CT-B and CT-K along the dentin organic matrix and also indicated co-occurrence of MMPs and CTs in that tissue. The enzyme kinetics studies showed proteolytic activity in dentin extracts for both classes of proteases. Furthermore, it was observed that, at least for sound human dentin matrices, the activity of MMPs seems to be predominant over the CTs one. (C) 2016 Elsevier Ltd. All rights reserved.Peer reviewe

    Efeitos da cadeia produtiva mineral sobre os territórios: Uma análise dos casos do Banco de Dados Recursos Minerais e Territórios do CETEM / Effects of the mineral production chain on territories: An analysis of the cases of CETEM's Database of Mineral Resources and Territories

    Get PDF
    A ampliação global dos investimentos no setor de infraestrutura nas últimas décadas, impulsionado especialmente pela expansão econômica da China, gerou também o aumento da demanda internacional por recursos naturais. Com a expansão desse mercado, o Brasil se tornou um dos principais exportadores de minérios, chegando a ocupar o segundo lugar no ranking mundial em 2013. Neste cenário, o presente artigo mostra alguns aspectos dos impactos que essa expansão da cadeia produtiva mineral brasileira gerou sobre os territórios. A partir das informações disponibilizados pelo Banco de Dados Recursos Minerais e Territórios do Centro de Tecnologia Mineral (CETEM/MCTI), serão apresentadas a distribuição geográfica dos casos, a incidência das substâncias minerais nesses casos e em quais categorias e tipologias de impactos eles estão classificados

    BRS 277: Wheat cultivar

    Get PDF
    The wheat cultivar ‘BRS 277’ was developed by Embrapa (Empresa Brasileira de Pesquisa Agropecuária),resulting from a cross between OR1 and Coker 97-33. The plant height of ‘BRS 277’ is short, frost resistance in the vegetativestage is good and resistance to leaf rust moderate

    Equine ovarian tissue xenografting: impacts of cooling, vitrification, and VEGF.

    Get PDF
    Ovarian tissue transplantation methods using cooled and cryopreserved samples have been attractive options for fertility preservation in animal models and humans. The aim of this study was to evaluate the impact of previous exposure to cooling, cryopreservation, and VEGF on the overall efficiency of equine ovarian tissue after heterotopic xenotransplantation in mice. The end points evaluated were follicular morphology and development, follicular and stromal cell densities, angiogenesis (i.e. the density of new and mature blood vessels), collagen types I and III fiber densities, and total fibrosis. Ovaries of adult mares were harvested after ovariectomy, and ovarian fragments were xenografted in the i.p. wall of BALB nude mice. Ten types of treatments involving different combinations of cooling, cryopreservation, xenografting procedures, and VEGF exposure were compared. The novel aspect of this study was the use of equine ovarian tissue xenotransplantation in mice, challenging the fragments with different combinations of treatments. The main findings were (i) cooling but not cryopreservation was effective in preserving the follicular morphology, (ii) a greater percentage of developing follicles but lower follicular and stromal cell densities were observed after ovarian tissue engraftment, (iii) exposure to VEGF increased new and mature vessels in cryopreserved-transplanted tissue, and (iv) an appropriate balance in the collagen types I and III fiber ratio in cooling-transplanted tissue was observed after exposure to VEGF. This study contributes to advancing knowledge in the preservation of ovarian tissue after cooling-cryopreservation and transplantation aiming to be applied to genetically superior/valuable horses, livestock, endangered animals, and, possibly, humans. LAY SUMMARY: Due to ethical limitations involving humans, the female horse (mare) has recently emerged as an alternative model for reproductive comparisons with women to optimize fertility restoration using ovarian tissue transplantation techniques. This study determined if ovarian tissue from donor mares (n = 3), exposed or not to vascular endothelial growth factor (VEGF) before transplantation, better survives for 7 days after transplantation into mouse hosts (n = 12). Tissues submitted to different combinations of cooling, freezing, and transplanting treatments, along with control groups, were evaluated using the parameters morphology, development, the density of immature eggs (follicles), the density of supportive (stromal) cells, collagen protein proportions, and density of blood vessels. Frozen-thawed treatments had lower percentages of normal follicles. Exposure to VEGF increased blood vessel densities in frozen tissue and favored adequate collagen levels in cooled-transplanted treatments. In conclusion, VEGF exposure seems to be beneficial for mare ovarian tissue transplantation and warrants further investigation

    BRS Guamirim: bread wheat cultivar, early cycle and short stature

    Get PDF
    A cultivar de trigo BRS Guamirim foi desenvolvida pela Embrapa e resultou de um cruzamento entre os genitores Embrapa 27/Buck Nandu e PF 93159. Possui ciclo precoce, baixa estatura de planta e intenso afilhamento. Apresenta equilibrada reação às principais moléstias do trigo, pertence à classe pão e demonstra adaptabilidade às diferentes regiões tritícolas do país, com estabilidade de produção. Seu potencial de rendimento é superior a 5 t ha-1.Wheat cultivar BRS Guamirim was developed by Embrapa and resulted from a cross among Embrapa 27/Buck Nandu and PF 93159. BRS Guamirim has early cycle, short plant stature and high tillering. It shows equilibrate behaviour to mainly wheat deseases, belongs to bread class and is adapted to different wheat regions, showing production stability. Its grain yield potential is higher than 5 t ha-1

    Proto-Adamastor ocean crust (920 Ma) described in Brasiliano Orogen from coetaneous zircon and tourmaline.

    Get PDF
    Proto-Adamastor ocean bathed Rodinia and successor continental fragments from 1.0e0.9 Ga up to 0.75 Ga, and evolved into world Adamastor Ocean at 0.75e0.60 Ga. Mesoproterozoic oceanic crust is poorly preserved on continents, only indirect evidence registered in Brasiliano Orogen. We report first evidence of ophiolite originated in proto-Adamastor. We use multi-technique U-Pb-Hf zircon and d11B tourmaline isotopic and elemental compositions. The host tourmalinite is enclosed in metaserpentinite, both belonging to the Bossoroca ophiolite. Zircon is 920 Ma-old, 3 Hf(920 Ma)??12, HfTDM ? 1.0 Ga and has ?oceanic? composition (e.g., U/Yb < 0.1). Tourmaline is dravite with d11B ? ?1.8& (Tur 1), 0& (Tur 2), 8.5& (Tur 3). These characteristics are a novel contribution to Rodinia and associated world ocean, because a fragment of proto-Adamastor oceanic crust and mantle evolved at the beginning of the Brasiliano Orogen
    corecore