2,653 research outputs found

    Almost Contact Lagrangian Submanifolds of Nearly Kaehler 6-Sphere

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    For a Lagrangian submanifold M of S 6 with nearly Kaehler structure, we provide conditions for a canonically induced almost contact metric structure on M by a unit vector field, to be Sasakian. Assuming M contact metric, we show that it is Sasakian if and only if the second fundamental form annihilates the Reeb vector field ξ, furthermore, if the Sasakian submanifold M is parallel along ξ, then it is the totally geodesic 3-sphere. We conclude with a condition that reduces the normal canonical almost contact metric structure on M to Sasakian or cosymplectic structure

    Fotografía y memoria: huellas del pasado, lecturas desde el presente

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    "Fotografía y memoria, dos significantes que parecen enlazarse ya en el momento mismo del encuadre que la cámara registra y que la imagen nos trae al presente como una confirmación del pasado: esto sucedió. Una temporalidad en suspenso, que espera su despertar en la mirada que la traerá al mundo nuevamente, inquisidora, curiosa, amorosa o compasiva. Pero esa realidad capturada que puede estar allí, a la vista de todos, tiene el poder de hablarle a cada uno en singular. Y ese es quizá su don, el de poner en diálogo, en el destello de una imagen, lo íntimo y lo común. Un diálogo que es también entre quien apresó ese instante en el correr inclemente de los días y en ese lugar del mundo ‒la fotografía es tanto temporal como espacial y, por ende, un lugar de memoria‒ y quien se asoma a ella, por azar o por necesidad, en una búsqueda o un encuentro. Y aquí confluyen la distancia que la imagen atempera y su fondo, inasible, como nos lo advirtiera Jean-Luc Nancy, una profundidad que escapa a la percepción y hace a su misterio. Presencia y ausencia, podríamos decir, esa tensión inevitable entre lo que revela y lo que oculta. Y es quizá en la fotografía, cuyo efecto de verdad no logró borrar el avance de la técnica, donde la imagen que se ofrece a la mirada se torna con mayor intensidad hacia el interior, hacia la intimidad, un “fondo” en el cual queda fijado el contorno impreciso de lo visto en su doble inadecuación: respecto de lo real dejado a distancia por la imagen y respecto de la imagen misma, despegada ya de su materialidad para quedar en la memoria como “una huella en la cera” ‒una afección en el alma‒ con esa potencialidad que señala la aporía aristotélica, de “hacer presente lo que está ausente”. De esa interioridad ‒y de esas afecciones‒ habla este libro, a partir de fotografías que de diversas maneras interpelan lo común. Y es allí donde se despliega el lazo indiscernible entre lo individual y lo colectivo, aquello compartido que con toda temperancia podemos llamar “memoria” para inmediatamente abrirlo a su plural, memorias. Una apertura, un diálogo, una “conversación grupal”, como diría Michael Holroyd, el reconocido biógrafo inglés, a la que también convocan las voces de este libro." (Leonor Arfuch, Prólogo).Fil: Schafer, David . Universidad de Nacional de Córdoba. Facultad de Ciencias Sociales. Centro de Estudios Avanzados; Argentina

    Q methodology and a Delphi poll: a useful approach to researching a narrative approach to therapy

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    Q methodology and a Delphi poll combined qualitative and quantitative methods to explore definitions of White and Epston's (1990) narrative approach to therapy among a group of UK practitioners. A Delphi poll was used to generate statements about narrative therapy. The piloting of statements by the Delphi panel identified agreement about theoretical ideas underpinning narrative therapy and certain key practices. A wider group of practitioners ranked the statements in a Q sort and made qualitative comments about their sorting. Quantitative methods (principal components analysis) were used to extract eight accounts of narrative therapy, five of which are qualitatively analysed in this paper. Agreement and differences were identified across a range of issues, including the social construction of narratives, privileging a political stance or narrative techniques and the relationship with other therapies, specifically systemic psychotherapy. Q methodology, combined with the Delphi poll, was a unique and innovative feature of this study

    A repurposing strategy for Hsp90 inhibitors demonstrates their potency against filarial nematodes

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    Novel drugs are required for the elimination of infections caused by filarial worms, as most commonly used drugs largely target the microfilariae or first stage larvae of these infections. Previous studies, conducted in vitro, have shown that inhibition of Hsp90 kills adult Brugia pahangi. As numerous small molecule inhibitors of Hsp90 have been developed for use in cancer chemotherapy, we tested the activity of several novel Hsp90 inhibitors in a fluorescence polarization assay and against microfilariae and adult worms of Brugia in vitro. The results from all three assays correlated reasonably well and one particular compound, NVP-AUY922, was shown to be particularly active, inhibiting Mf output from female worms at concentrations as low as 5.0 nanomolar after 6 days exposure to drug. NVP-AUY922 was also active on adult worms after a short 24 h exposure to drug. Based on these in vitro data, NVP-AUY922 was tested in vivo in a mouse model and was shown to significantly reduce the recovery of both adult worms and microfilariae. These studies provide proof of principle that the repurposing of currently available Hsp90 inhibitors may have potential for the development of novel agents with macrofilaricidal properties

    Soil Moisture and Fungi Affect Seed Survival in California Grassland Annual Plants

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    Survival of seeds in the seed bank is important for the population dynamics of many plant species, yet the environmental factors that control seed survival at a landscape level remain poorly understood. These factors may include soil moisture, vegetation cover, soil type, and soil pathogens. Because many soil fungi respond to moisture and host species, fungi may mediate environmental drivers of seed survival. Here, I measure patterns of seed survival in California annual grassland plants across 15 species in three experiments. First, I surveyed seed survival for eight species at 18 grasslands and coastal sage scrub sites ranging across coastal and inland Santa Barbara County, California. Species differed in seed survival, and soil moisture and geographic location had the strongest influence on survival. Grasslands had higher survival than coastal sage scrub sites for some species. Second, I used a fungicide addition and exotic grass thatch removal experiment in the field to tease apart the relative impact of fungi, thatch, and their interaction in an invaded grassland. Seed survival was lower in the winter (wet season) than in the summer (dry season), but fungicide improved winter survival. Seed survival varied between species but did not depend on thatch. Third, I manipulated water and fungicide in the laboratory to directly examine the relationship between water, fungi, and survival. Seed survival declined from dry to single watered to continuously watered treatments. Fungicide slightly improved seed survival when seeds were watered once but not continually. Together, these experiments demonstrate an important role of soil moisture, potentially mediated by fungal pathogens, in driving seed survival

    The effect of ozone on progression or regression of artificial caries-like enamel lesions in vitro

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    Objective: This study investigated the effect of ozone on the progression or regression of artificial caries-like lesions on enamel following pH cycling conditions in vitro. Methods: A randomized, single blind, four legs design was used. 20 full thickness enamel slabs were allocated to each of the four groups which were: Fluoride free toothpaste (control); ozone alone; Reductant/Patient Kit alone and a combination of both ozone/Reductant/Patient Kit. Artificial lesions were created and subjected to the pH cycling regime for a 14 days period. Assessments were carried out before and after the pH cycling on the slabs using the microhardness testing and Quantitative Light-induced Fluorescence (QLF). Results: Statistical significant difference were found in the percentage change of enamel microhardness before and after pH cycling between ozone/Reductant/Patient Kit group and all the other three groups of the study, as well as between Reductant/Patient Kit group and control. There was a statistical significant difference in the change of size and severity of the lesion (ΔQ) between all the three regimes tested and the control with a trend favouring ozone/Reductant/Patient Kit group. Conclusions: In our model, it appeared that ozone treatment alone is not effective in protecting the enamel against demineralisation or promoting remineralisation, unless combined with the Reductant/Patient Kit, which contain high levels of fluoride

    Nuclear receptors in vascular biology

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    Nuclear receptors sense a wide range of steroids and hormones (estrogens, progesterone, androgens, glucocorticoid, and mineralocorticoid), vitamins (A and D), lipid metabolites, carbohydrates, and xenobiotics. In response to these diverse but critically important mediators, nuclear receptors regulate the homeostatic control of lipids, carbohydrate, cholesterol, and xenobiotic drug metabolism, inflammation, cell differentiation and development, including vascular development. The nuclear receptor family is one of the most important groups of signaling molecules in the body and as such represent some of the most important established and emerging clinical and therapeutic targets. This review will highlight some of the recent trends in nuclear receptor biology related to vascular biology

    Structural studies of T4S systems by electron microscopy

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    Abstract: Type IV secretion (T4S) systems are large dynamic nanomachines that transport DNA and/or proteins through the membranes of bacteria. Analysis of T4S system architecture is an extremely challenging task taking into account their multi protein organisation and lack of overall global symmetry. Nonetheless the last decade demonstrated an amazing progress achieved by X-ray crystallography and cryo-electron microscopy. In this review we present a structural analysis of this dynamic complex based on recent advances in biochemical, biophysical and structural studies

    Underexpression of Deleted in liver cancer 2 (DLC2) is associated with overexpression of RhoA and poor prognosis in hepatocellular carcinoma

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    <p>Abstract</p> <p>Background</p> <p>DLC2, a unique RhoGAP, has been recently identified as a tumor suppressor gene in hepatocellular carcinoma (HCC). However, the expression of DLC2 protein, and its relationship with RhoA in clinical hepatocellular carcinoma have not been studied. The aim of this study was to investigate the DLC2 protein expression and its correlation with expression of RhoA, as well as to evaluate the prognostic value of DLC2 for HCC patients.</p> <p>Methods</p> <p>Western blot and immunohistochemical staining were employed to detect DLC2 protein expression in 128 HCC specimens. The correlation between DLC2 protein expression and clinicopathologic outcome, and prognostic value of DLC2 for HCC patients were analyzed.</p> <p>Results</p> <p>HCC tissues revealed significantly lower level of DLC2 protein than pericarcinomatous liver tissues (PCLT). There was significant correlation between underexpression of DLC2 protein and cell differentiation. Meanwhile, underexpression of DLC2 protein was correlated with overexression of RhoA. Furthermore, HCC Patients with DLC2-negative expression showed a significantly poorer prognosis than those with DLC2-positve expression.</p> <p>Conclusion</p> <p>Our data strongly suggested that decreased DLC2 expression in HCC correlates with cell differentiation of HCC and overexpression of RhoA, underexpression of DLC2 is associated with poor prognosis in HCC patients.</p
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