1,308 research outputs found

    Evolution of Chagas’ disease in Brazil. Epidemiological perspective and challenges for the future: a critical review

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    Aims: This paper aimed to provide a critical review of the evolution of Chagas’ disease in Brazil, its magnitude, historical development and management, and challenges for the future. Methods: A literature search was performed using PubMed, SciELO and Google Scholar and throughout collected articles’ references. Narrative analysis was structured around five main themes identified: vector transmission, control program, and transfusion, oral and congenital transmission. Results: In Brazil, the Chagas’ disease Control Program was fully implemented in the 1980s, when it reached practically all the endemic areas, and in 1991, the Southern Cone Initiative was created, aiming to eliminate the disease transmission through eliminating the Triatoma infestans and controlling blood banks. As a result, the prevalence of chagasic donors in blood banks reduced from 4.4% in the 80s to 0.2% in 2005. In 2006, PAHO certified the interruption of transmission of Chagas’ disease through this vector in Brazil. However, there are still challenges, such as the domiciliation of new vector species, the need for medical care of the infected individuals, the prevention of alternative mechanisms of transmission, the loss of political concern regarding the disease and, the weakening of the control program. Conclusion: Despite the progress towards control, there are still many challenges ahead to maintain and expand such control and minimise the risk of re-emergence

    Pull-out and push-in tests of bonded steel strands

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    Martí Vargas, JR. (2013). Pull-out and push-in tests of bonded steel strands. Magazine of Concrete Research. 65(18):1128-1131. doi:10.1680/macr.13.00061S112811316518Balázs LG .Bond Model with Non-Linear Bond-Slip Law, 1987, Politecnico di Milano, Italy, 395–430, Studi e Ricerche, Post-Graduate Course for Reinforced Concrete Structures, V.8/86.Balazs, G. L. (1992). Transfer Control of Prestressing Strands. PCI Journal, 37(6), 60-71. doi:10.15554/pcij.11011992.60.71Balazs, G. L. (1993). Transfer Length of Prestressing Strand as a Function of Draw-In and Initial Prestress. PCI Journal, 38(2), 86-93. doi:10.15554/pcij.03011993.86.93Balázs, G. L. (2007). Connecting Reinforcement to Concrete by Bond. Beton- und Stahlbetonbau, 102(S1), 46-50. doi:10.1002/best.200710109Carmo RNF .Ancoragem de Armaduras Pré-Esforçadas por Pré-Tensão. MSc thesis, 1999, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, Portugal, (in Portuguese).Faria, D. M. V., Lúcio, V. J. G., & Pinho Ramos, A. (2011). Pull-out and push-in tests of bonded steel strands. Magazine of Concrete Research, 63(9), 689-705. doi:10.1680/macr.2011.63.9.689Faria, D. M. V., Lúcio, V. J. G., & Ramos, A. P. (2011). Strengthening of flat slabs with post-tensioning using anchorages by bonding. Engineering Structures, 33(6), 2025-2043. doi:10.1016/j.engstruct.2011.02.039Faria, D. M. V., Lúcio, V. J. G., & Pinho Ramos, A. (2012). Post-punching behaviour of flat slabs strengthened with a new technique using post-tensioning. Engineering Structures, 40, 383-397. doi:10.1016/j.engstruct.2012.03.014Laldji S .Bond Characteristics of Prestressing Strand in Grout. MPhil thesis, 1987, University of Leicester, UK.Laldji, S., & Young, A. G. (1988). Bond between steel strand and cement grout in ground anchorages. Magazine of Concrete Research, 40(143), 90-98. doi:10.1680/macr.1988.40.143.90Lopes, S. M. R., & do Carmo, R. N. F. (2002). Bond of prestressed strands to concrete: transfer rate and relationship between transmission length and tendon draw-in. Structural Concrete, 3(3), 117-126. doi:10.1680/stco.2002.3.3.117Martí-Vargas, J. R., Serna-Ros, P., Fernández-Prada, M. A., Miguel-Sosa, P. F., & Arbeláez, C. A. (2006). Test method for determination of the transmission and anchorage lengths in prestressed reinforcement. Magazine of Concrete Research, 58(1), 21-29. doi:10.1680/macr.2006.58.1.21Marti-Vargas, J. R., Arbelaez, C. A., Serna-Ros, P., Navarro-Gregori, J., & Pallares-Rubio, L. (2007). Analytical model for transfer length prediction of 13 mm prestressing strand. Structural Engineering and Mechanics, 26(2), 211-229. doi:10.12989/sem.2007.26.2.211Palmer, K. D., & Schultz, A. E. (2011). Experimental investigation of the web-shear strength of deep hollow-core units. PCI Journal, 56(4), 83-104. doi:10.15554/pcij.09012011.83.10

    Theoretical study of the insulating oxides and nitrides: SiO2, GeO2, Al2O3, Si3N4, and Ge3N4

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    An extensive theoretical study is performed for wide bandgap crystalline oxides and nitrides, namely, SiO_{2}, GeO_{2}, Al_{2}O_{3}, Si_{3}N_{4}, and Ge_{3}N_{4}. Their important polymorphs are considered which are for SiO_{2}: α\alpha-quartz, α\alpha- and β\beta-cristobalite and stishovite, for GeO_{2}: α\alpha-quartz, and rutile, for Al_{2}O_{3}: α\alpha-phase, for Si_{3}N_{4} and Ge_{3}N_{4}: α\alpha- and β\beta-phases. This work constitutes a comprehensive account of both electronic structure and the elastic properties of these important insulating oxides and nitrides obtained with high accuracy based on density functional theory within the local density approximation. Two different norm-conserving \textit{ab initio} pseudopotentials have been tested which agree in all respects with the only exception arising for the elastic properties of rutile GeO_{2}. The agreement with experimental values, when available, are seen to be highly satisfactory. The uniformity and the well convergence of this approach enables an unbiased assessment of important physical parameters within each material and among different insulating oxide and nitrides. The computed static electric susceptibilities are observed to display a strong correlation with their mass densities. There is a marked discrepancy between the considered oxides and nitrides with the latter having sudden increase of density of states away from the respective band edges. This is expected to give rise to excessive carrier scattering which can practically preclude bulk impact ionization process in Si_{3}N_{4} and Ge_{3}N_{4}.Comment: Published version, 10 pages, 8 figure

    Pogostick: A New Versatile piggyBac Vector for Inducible Gene Over-Expression and Down-Regulation in Emerging Model Systems

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    Non-traditional model systems need new tools that will enable them to enter the field of functional genetics. These tools should enable the exploration of gene function, via knock-downs of endogenous genes, as well as over-expression and ectopic expression of transgenes.We constructed a new vector called Pogostick that can be used to over-express or down-regulate genes in organisms amenable to germ line transformation by the piggyBac transposable element. Pogostick can be found at www.addgene.org, a non-profit plasmid repository. The vector currently uses the heat-shock promoter Hsp70 from Drosophila to drive transgene expression and, as such, will have immediate applicability to organisms that can correctly interpret this promotor sequence. We detail how to clone candidate genes into this vector and test its functionality in Drosophila by targeting a gene coding for the fluorescent protein DsRed. By cloning a single DsRed copy into the vector, and generating transgenic lines, we show that DsRed mRNA and protein levels are elevated following heat-shock. When cloning a second copy of DsRed in reverse orientation into a flanking site, and transforming flies constitutively expressing DsRed in the eyes, we show that endogenous mRNA and protein levels drop following heat-shock. We then test the over-expression vector, containing the complete cDNA of Ultrabithorax (Ubx) gene, in an emerging model system, Bicyclus anynana. We produce a transgenic line and show that levels of Ubx mRNA expression rise significantly following a heat-shock. Finally, we show how to obtain genomic sequence adjacent to the Pogostick insertion site and to estimate transgene copy number in genomes of transformed individuals.This new vector will allow emerging model systems to enter the field of functional genetics with few hurdles

    Intrinsic genetic characteristics determine tumor-modifying capacity of fibroblasts: matrix metalloproteinase-3 5A/5A genotype enhances breast cancer cell invasion

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    Background Stromal fibroblasts can contribute to tumor invasion through the release of matrix metalloproteinases (MMPs). Population studies have suggested that single nucleotide polymorphisms (SNPs) in MMP genes influence levels of expression and may be associated with breast cancer risk and with disease progression. This study directly examined the impact of MMP SNP genotype on the ability of host fibroblasts to promote tumor cell invasion. Methods Primary breast fibroblasts were isolated from patients with (n = 13) or without (n = 19) breast cancer, and their ability to promote breast cancer cell invasion was measured in in vitro invasion assays. Fibroblast invasion-promoting capacity (IPC) was analyzed in relation to donor type (tumor or non-tumor patient), MMP-1, MMP-3, and MMP-9 SNP genotype and MMP activity using independent samples t test and analysis of variance. All statistical tests were two-sided. Results Tumor-derived fibroblasts promoted higher levels of invasion than normal fibroblasts (p = 0.041). When IPC was related to genotype, higher levels of IPC were generated by tumor fibroblasts with the high-expressing MMP-3 5A/5A genotype compared with the 5A/6A and 6A/6A genotypes (p = 0.05 and 0.07, respectively), and this was associated with enhanced MMP-3 release. The functional importance of MMP-3 was demonstrated by enhanced invasion in the presence of recombinant MMP-3, whereas reduction occurred in the presence of a specific MMP-3 inhibitor. An inverse relationship was demonstrated between fibroblast IPC and the high-expressing MMP-1 genotype (p = 0.031), but no relationship was seen with MMP-9 SNP status. In contrast, normal fibroblasts showed no variation in IPC in relation to MMP genotype, with MMP-3 5A/5A fibroblasts exhibiting significantly lower levels of IPC than their tumor-derived counterparts (p = 0.04). Conclusion This study has shown that tumor-derived fibroblasts exhibit higher levels of IPC than normal fibroblasts and that the MMP-3 5A/5A genotype contributes to this through enhanced MMP-3 release. Despite a high-expressing genotype, normal fibroblasts do not exhibit higher IPC or enhanced MMP release. This suggests that more complex changes occur in tumor-derived fibroblasts, enabling full expression of the MMP SNP genotype and these possibly are epigenetic in nature. The results do suggest that, in women with breast cancer, a high-expressing MMP-3 genotype may promote tumor progression more effectively

    Sequence-Based Genotyping for Marker Discovery and Co-Dominant Scoring in Germplasm and Populations

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    Conventional marker-based genotyping platforms are widely available, but not without their limitations. In this context, we developed Sequence-Based Genotyping (SBG), a technology for simultaneous marker discovery and co-dominant scoring, using next-generation sequencing. SBG offers users several advantages including a generic sample preparation method, a highly robust genome complexity reduction strategy to facilitate de novo marker discovery across entire genomes, and a uniform bioinformatics workflow strategy to achieve genotyping goals tailored to individual species, regardless of the availability of a reference sequence. The most distinguishing features of this technology are the ability to genotype any population structure, regardless whether parental data is included, and the ability to co-dominantly score SNP markers segregating in populations. To demonstrate the capabilities of SBG, we performed marker discovery and genotyping in Arabidopsis thaliana and lettuce, two plant species of diverse genetic complexity and backgrounds. Initially we obtained 1,409 SNPs for arabidopsis, and 5,583 SNPs for lettuce. Further filtering of the SNP dataset produced over 1,000 high quality SNP markers for each species. We obtained a genotyping rate of 201.2 genotypes/SNP and 58.3 genotypes/SNP for arabidopsis (n = 222 samples) and lettuce (n = 87 samples), respectively. Linkage mapping using these SNPs resulted in stable map configurations. We have therefore shown that the SBG approach presented provides users with the utmost flexibility in garnering high quality markers that can be directly used for genotyping and downstream applications. Until advances and costs will allow for routine whole-genome sequencing of populations, we expect that sequence-based genotyping technologies such as SBG will be essential for genotyping of model and non-model genomes alike

    Phosphorylation of Nrf2 at Multiple Sites by MAP Kinases Has a Limited Contribution in Modulating the Nrf2-Dependent Antioxidant Response

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    The bZIP transcription factor Nrf2 has emerged as a pivotal regulator of intracellular redox homeostasis by controlling the expression of many endogenous antioxidants and phase II detoxification enzymes. Upon oxidative stress, Nrf2 is induced at protein levels through redox-sensitive modifications on cysteine residues of Keap1, a component of the E3 ubiquitin ligase that targets Nrf2 for ubiquitin-dependent degradation. The mitogen activated protein kinases (MAPKs) have previously been proposed to regulate Nrf2 in response to oxidative stress. However, the exact role of MAPKs and the underlying molecular mechanism remain poorly defined. Here we report the first evidence that Nrf2 is phosphorylated in vivo by MAPKs. We have identified multiple serine/threonine residues as major targets of MAPK-mediated phosphorylation. Combined alanine substitution on those residues leads to a moderate decrease in the transcriptional activity of Nrf2, most likely due to a slight reduction in its nuclear accumulation. More importantly, Nrf2 protein stability, primarily controlled by Keap1, is not altered by Nrf2 phosphorylation in vivo. These data indicate that direct phosphorylation of Nrf2 by MAPKs has limited contribution in modulating Nrf2 activity. We suggest that MAPKs regulate the Nrf2 signaling pathway mainly through indirect mechanisms

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

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    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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