1,243 research outputs found

    Emphysematous Pyelonephritis

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    Os autores apresentam um caso de pielonefrite enfisematosa a E. coli, numa doente diabética de 63 anos. Os exames imagiológicos(Rx simples do abdómen, ultrassonografia e tomografia computorizada) permitiram estabelecer o diagnóstico. A nefrostomia percutânea, combinada com o tratamento médico, contribuiu para a favorável evolução clínica

    Endovascular Therapy of Pseudoaneurysm and Arteriovenous Fistula in a Renal Graft

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    A 31 year old male Caucasian received a renal cadaveric allograft. Reconstruction of an inferior polar artery was corrected pre-implantation. Delayed graft function occurred leading to dialysis support for one month. Graft biopsies(days 7, 15) showed acute tubular necrosis(ATN) and no rejection. Serial ultrasound (US), performed on average weekly, were compatible with ATN. On day 31, Doppler US and a CAT scan suggested for the first time a pseudoaneurysm adjacent to the implantation of the graft artery on the external iliac artery. For clinical and technical reasons, arteriography was only performed on day 67, when serum creatinine was 3.3 mg/dl. It showed a large pseudoaneurysm with an arteriovenous fistula to the right common iliac vein. Compression of the right external iliac artery was clear. In an attempt to close the arteriovenous fistula, the communication with the pseudoaneurysm was embolised with gelfoam and metallic coils with partial success. One week later, by right femoral approach a covered wallstent was placed immediately below the origin of the graft artery.Subsequent Doppler US and arteriography con-firmed closure of the communication with thepseudoaneurysm and of the arteriovenous fistula. The calibre of the right external iliac artery was then normal. By month 18, serum creatinine is stable at 2.1 mg/dl. We can only speculate on the origin of thepseudoaneurysm and of the AV fistula, whichwere not evident until one month post-transplantation. Backtable surgery was performed on thepolar not the main graft artery. Invasive angiography was irreplaceable in this unusual clinical situation

    Pedagogy subjects in the formation and in the construction of representations about teachers' work: views of preservice Chemistry and Physics teachers

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    Este estudo tem como objetivo analisar as concepções de licenciandos em Química e em Física sobre a prática profissional e as marcas deixadas pelas disciplinas pedagógicas na sua formação, assim como identificar sinais de mudanças em suas concepções durante a realização do curso de Licenciatura. Para tanto, textos foram produzidos por 54 alunos matriculados em cursos de Licenciatura de duas universidades públicas do estado de São Paulo, nos quais os licenciandos expressaram suas experiências de formação e apontaram elementos que consideram que terão alguma influência em sua atuação profissional. Os textos revelaram que as ideias que os licenciandos carregam são consistentes com muitas das visões e objetivos apresentados em cursos de formação de professores. Nas produções dos estudantes faz-se presente o desejo de compartilhar e promover em seus futuros alunos o interesse pela Química e a Física. Os seus comentários refletiram visões de professores que tiveram no passado, os quais gostariam de imitar, e de outros que não gostariam de ser. Os comentários também tornaram evidente a vontade dos licenciandos em se estabelecerem como professores que se preocupam com seus alunos. Os textos foram analisados segundo a Análise do Discurso de linha francesa, como tem sido divulgada por Eni Orlandi, especialmente a noção de formação discursiva.The objective of this study is to analyze the views of preservice chemistry and physics teachers about the professional practice and the influence of pedagogic disciplines on their formation. Furthermore, it aims at identifying changes in preservice teachers' opinions and beliefs throughout their education. Hence, texts were produced by 54 undergraduate students who were undertaking preservice courses in two public universities in the state of São Paulo, in which they expressed their experiences throughout the course and mentioned relevant aspects about their professional development. The texts revealed that their ideas were consistent concerning many of the views and goals of teacher preparation courses. Their statements reflected desires to share and stimulate interest for chemistry and physics in their future students. Their comments evidenced past experiences they would like to emulate and others they would rather not. They also expressed their worries about becoming teachers who do care for their students. The texts were analyzed by Discourse Analysis, in its French approach, according to Eni Orlandi, especially the concept of discursive formation

    Electronic transport in polycrystalline graphene

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    Most materials in available macroscopic quantities are polycrystalline. Graphene, a recently discovered two-dimensional form of carbon with strong potential for replacing silicon in future electronics, is no exception. There is growing evidence of the polycrystalline nature of graphene samples obtained using various techniques. Grain boundaries, intrinsic topological defects of polycrystalline materials, are expected to dramatically alter the electronic transport in graphene. Here, we develop a theory of charge carrier transmission through grain boundaries composed of a periodic array of dislocations in graphene based on the momentum conservation principle. Depending on the grain boundary structure we find two distinct transport behaviours - either high transparency, or perfect reflection of charge carriers over remarkably large energy ranges. First-principles quantum transport calculations are used to verify and further investigate this striking behaviour. Our study sheds light on the transport properties of large-area graphene samples. Furthermore, purposeful engineering of periodic grain boundaries with tunable transport gaps would allow for controlling charge currents without the need of introducing bulk band gaps in otherwise semimetallic graphene. The proposed approach can be regarded as a means towards building practical graphene electronics.Comment: accepted in Nature Material

    In vitro culture with gemcitabine augments death receptor and NKG2D ligand expression on tumour cells

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    Much effort has been made to try to understand the relationship between chemotherapeutic treatment of cancer and the immune system. Whereas much of that focus has been on the direct effect of chemotherapy drugs on immune cells and the release of antigens and danger signals by malignant cells killed by chemotherapy, the effect of chemotherapy on cells surviving treatment has often been overlooked. In the present study, tumour cell lines: A549 (lung), HCT116 (colon) and MCF-7 (breast), were treated with various concentrations of the chemotherapeutic drugs cyclophosphamide, gemcitabine (GEM) and oxaliplatin (OXP) for 24 hours in vitro. In line with other reports, GEM and OXP upregulated expression of the death receptor CD95 (fas) on live cells even at sub-cytotoxic concentrations. Further investigation revealed that the increase in CD95 in response to GEM sensitised the cells to fas ligand treatment, was associated with increased phosphorylation of stress activated protein kinase/c-Jun N-terminal kinase and that other death receptors and activatory immune receptors were co-ordinately upregulated with CD95 in certain cell lines. The upregulation of death receptors and NKG2D ligands together on cells after chemotherapy suggest that although the cells have survived preliminary treatment with chemotherapy they may now be more susceptible to immune cell-mediated challenge. This re-enforces the idea that chemotherapy-immunotherapy combinations may be useful clinically and has implications for the make-up and scheduling of such treatments

    Criticality in correlated quantum matter

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    At quantum critical points (QCP) \cite{Pfeuty:1971,Young:1975,Hertz:1976,Chakravarty:1989,Millis:1993,Chubukov:1 994,Coleman:2005} there are quantum fluctuations on all length scales, from microscopic to macroscopic lengths, which, remarkably, can be observed at finite temperatures, the regime to which all experiments are necessarily confined. A fundamental question is how high in temperature can the effects of quantum criticality persist? That is, can physical observables be described in terms of universal scaling functions originating from the QCPs? Here we answer these questions by examining exact solutions of models of correlated systems and find that the temperature can be surprisingly high. As a powerful illustration of quantum criticality, we predict that the zero temperature superfluid density, ρs(0)\rho_{s}(0), and the transition temperature, TcT_{c}, of the cuprates are related by Tcρs(0)yT_{c}\propto\rho_{s}(0)^y, where the exponent yy is different at the two edges of the superconducting dome, signifying the respective QCPs. This relationship can be tested in high quality crystals.Comment: Final accepted version not including minor stylistic correction

    The Effects of Dasatinib in Experimental Acute Respiratory Distress Syndrome Depend on Dose and Etiology

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    Background/Aims: Evidence suggests that tyrosine-kinase inhibitors may attenuate lung inflammation and fibrosis in experimental acute respiratory distress syndrome (ARDS). We hypothesized that dasatinib, a tyrosine-kinase inhibitor, might act differently depending on the ARDS etiology and the dose. Methods: C57/BL6 mice were divided to be pre-treated with dasatinib (1mg/kg or 10mg/kg) or vehicle (1% dimethyl-sulfoxide) by oral gavage. Thirty-minutes after pre-treatment, mice were subdivided into control (C) or ARDS groups. ARDS animals received Escherichia coli lipopolysaccharide intratracheally (ARDSp) or intraperitoneally (ARDSexp). A new dose of dasatinib or vehicle was administered at 6 and 24h. Results: Forty-eight hours after ARDS induction, dasatinib 1mg/kg yielded: improved lung morphofunction and reduced cells expressing toll-like receptor (TLR)-4 in lung, independent of ARDS etiology; reduced neutrophil and levels of interleukin (IL)-6, IL-10 and transforming growth factor (TGF)-β in ARDSp. The higher dose of dasatinib caused no changes in lung mechanics, diffuse alveolar damage, neutrophil, or cells expressing TLR4, but increased IL-6, vascular endothelial growth factor (VEGF), and cells expressing Fas receptor in lung in ARDSp. In ARDSexp, it improved lung morphofunction, increased VEGF, and reduced cells expressing TLR4. Conclusion: Dasatinib may have therapeutic potential in ARDS independent of etiology, but careful dose monitoring is required. © 2015 S. Karger AG, Basel

    Slipping through the net: Can data science approaches help target clean cooking policy interventions?

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    Reliance on solid biomass cooking fuels in India has negative health and socio-economic consequences for households, yet policies aimed at promoting uptake of LPG for cooking have not always been effective at promoting sustained transition to cleaner cooking amongst intended beneficiaries. This paper uses a two-step approach combining predictive and descriptive analyses of the IHDS panel dataset to identify different groups of households that switched stove between 2004/5 and 2011/12. A tree-based ensemble machine learning predictive analysis identifies key determinants of a switch from biomass to non-biomass stoves. A descriptive clustering analysis is used to identify groups of stove-switching households that follow different transition pathways. There are three key findings of this study: firstly non-income determinants of stove switching do not have a linear effect on stove switching, in particular variables on time of use and appliance ownership which offer a proxy for household energy practices; secondly location specific factors including region, infrastructure availability, and dwelling quality are found to be key determinants and as a result policies must be tailored to take into account local variations; thirdly some groups of households that adopt non-biomass stoves continue using biomass and interventions should be targeted to reduce their biomass use

    The Dynamics of Nestedness Predicts the Evolution of Industrial Ecosystems

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    In economic systems, the mix of products that countries make or export has been shown to be a strong leading indicator of economic growth. Hence, methods to characterize and predict the structure of the network connecting countries to the products that they export are relevant for understanding the dynamics of economic development. Here we study the presence and absence of industries at the global and national levels and show that these networks are significantly nested. This means that the less filled rows and columns of these networks' adjacency matrices tend to be subsets of the fuller rows and columns. Moreover, we show that nestedness remains relatively stable as the matrices become more filled over time and that this occurs because of a bias for industries that deviate from the networks' nestedness to disappear, and a bias for the missing industries that reduce nestedness to appear. This makes the appearance and disappearance of individual industries in each location predictable. We interpret the high level of nestedness observed in these networks in the context of the neutral model of development introduced by Hidalgo and Hausmann (2009). We show that, for the observed fills, the model can reproduce the high level of nestedness observed in these networks only when we assume a high level of heterogeneity in the distribution of capabilities available in countries and required by products. In the context of the neutral model, this implies that the high level of nestedness observed in these economic networks emerges as a combination of both, the complementarity of inputs and heterogeneity in the number of capabilities available in countries and required by products. The stability of nestedness in industrial ecosystems, and the predictability implied by it, demonstrates the importance of the study of network properties in the evolution of economic networks.Comment: 26 page
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