288 research outputs found

    DIE LINKE, Israel und der Antisemitismus : Thema beendet?

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    Memoria presentada en la Universidad de La Rioja para optar al grado de Doctor en QuĂ­mica por AlegrĂ­a Caballero MillĂĄn en Mayo de 2012.-- Bajo Licencia Creative Commons Reconocimiento-NoComercial-SinObraDerivada 3-0 Unported.En esta Memoria se exponen diversas aplicaciones de las O-aciloximas, compuestos que al ser irradiados fotoquĂ­micamente, generan un radical iminilo que es capaz de ciclar para dar lugar a heterociclos nitrogenados. Los objetivos de este Trabajo se detallan en el CapĂ­tulo 3 despuĂ©s de una pequeña introducciĂłn y de la exposiciĂłn de los Antecedentes (CapĂ­tulo 2). En este Ășltimo, se resume la reactividad fotoquĂ­mica de las O-aciloximas y su mecanismo de fotorreactividad por medio de tĂ©cnicas experimentales y computacionales. En el CapĂ­tulo 4, las O-aciloximas son irradiadas en presencia de carbenos de Fischer, lo que constituye el primer ejemplo descrito de este tipo de reacciones. Se ha demostrado que el radical iminilo generado fotoquĂ­micamente, es capaz de adicionarse a alquinil carbenos de Fischer dando lugar a 5-aza-1-metala-1,3,5- hexatrienos mediante un mecanismo de adiciĂłn 1,4; y a azepinas, si la adiciĂłn se efectĂșa de forma 1,2. En el CapĂ­tulo 5, se han sintetizado O-aciloximas mĂĄs complejas para obtener nuevos heterociclos nitrogenados mediante la ciclaciĂłn fotoquĂ­mica del radical iminilo. Esta metodologĂ­a ha sido utilizada para sintetizar productos naturales como la trisferidina y el precursor de alcaloides como la vasconina, pratosina, assoanina y oxoassoanina. En el CapĂ­tulo 6, se sintetizan por primera vez compuestos derivados de trisferidina al incorporar sustituyentes en las posiciones 7 y 10 del anillo de fenantridina. Se han estudiado las propiedades electroquĂ­micas y fotofĂ­sicas de estos compuestos y se han completado con cĂĄlculos teĂłricos DFT y TDDFT. AdemĂĄs, hemos comprobado que este tipo de derivados son fluorescentes y que son capaces de detectar protones e iones metĂĄlicos al observarse cambios en los espectros de fluorescencia. Por lo tanto, se han sintetizado nuevos compuestos que pueden utilizarse como sensores fluorescentes.Agradezco por su financiaciĂłn: -Consejo Superior de Investigaciones CientĂ­ficas, beca JAE predoctoral. -Proyecto CTQ2007-64197. -Proyecto CTQ2011-24800. -Universidad de La Rioja, API11/20 y ayudas EGI y ATUR.Peer Reviewe

    The relationship between chlorophyllous spores and mycorrhizal associations in ferns: evidence from an evolutionary approach

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    Premise: Approximately 14% of all fern species have physiologically active chlorophyllous spores that are much more short-lived than the more common and dormant achlorophyllous spores. Most chlorophyllous-spored species (70%) are epiphytes and account for almost 37% of all epiphytic ferns. Chlorophyllous-spored ferns are also overrepresented among fern species in habitats with waterlogged soils, of which nearly 60% have chlorophyllous spores. Ferns in these disparate habitat types also have a low incidence of mycorrhizal associations. We therefore hypothesized that autotrophic chlorophyllous spores represent an adaptation of ferns to habitats with scarce mycorrhizal associations. Methods: We evaluated the coevolution of chlorophyllous spores and mycorrhizal associations in ferns and their relation to habitat type using phylogenetic comparative methods. Results: Although we did not find support for the coevolution of spore type and mycorrhizal associations, we did find that chlorophyllous spores and the absence of mycorrhizal associations have coevolved with epiphytic and waterlogged habitats. Transition rates to epiphytic and waterlogged habitats were significantly higher in species with chlorophyllous spores compared to achlorophyllous lineages. Conclusions: Spore type and mycorrhizal associations appear to play important roles in the radiation of ferns into different habitat types. Future work should focus on clarifying the functional significance of these associations. Keywords: arbuscular mycorrhizae; chlorophyllous spores; correlated evolution; dark septate endophytes; epiphytes; grammitid; green spores; pteridophyte

    Comparison between linear and nonlinear systems of feed formulation for broilers

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    Two experiments were simultaneously carried out to compare feed formulation models: a linear model for minimum cost with a nonlinear model for maximum profitability for one-to 42-d-old broilers. One-dold male or female Cobb 500 broilers (n=2368) were allocated to one of the two trials according to sex. The experiments were performed simultaneously in an experimental poultry farm. Two housing densities were used: high density (HDH), with 14 birds/m2, and low density (LDH), with 10 birds/m2. The following treatments were evaluated: linear feed formulation and LDH (LF10); nonlinear formulation and LDH (NF10); linear formulation and HDH (LF14); and nonlinear formulation and HDH (NF14). A completely randomized design with four treatments of eight replicates each was applied. Performance and cost per kg of poultry were evaluated. Both formulation systems promoted similar broiler performance. However, the high-density feed using linear formulation reduced body weight in 42-d-old males, but not when nonlinear formulation was used. The NF10 treatment yielded the worst feed conversion ratio (p<0.05) and the lowest cost/kg broiler (p<0.05) for both sexes. The results demonstrate that the nutritional program that yields the best performance is not always the most economical one

    How scent and nectar influence floral antagonists and mutualists

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    Abstract Many plants attract and reward pollinators with floral scents and nectar, respectively, but these traits can also incur fitness costs as they also attract herbivores. This dilemma, common to most flowering plants, could be solved by not producing nectar and/or scent, thereby cheating pollinators. Both nectar and scent are highly variable in native populations of coyote tobacco, Nicotiana attenuata, with some producing no nectar at all, uncorrelated with the tobacco&apos;s main floral attractant, benzylacetone. By silencing benzylacetone biosynthesis and nectar production in all combinations by RNAi, we experimentally uncouple these floral rewards/attractrants and measure their costs/benefits in the plant&apos;s native habitat and experimental tents. Both scent and nectar increase outcrossing rates for three, separately tested, pollinators and both traits increase oviposition by a hawkmoth herbivore, with nectar being more influential than scent. These results underscore that it makes little sense to study floral traits as if they only mediated pollination services

    Noninvasive Visualization of the Activated αvÎČ3 Integrin in Cancer Patients by Positron Emission Tomography and [(18)F]Galacto-RGD

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    BACKGROUND: The integrin αvÎČ3 plays an important role in angiogenesis and tumor cell metastasis, and is currently being evaluated as a target for new therapeutic approaches. Several techniques are being studied to enable noninvasive determination of αvÎČ3 expression. We developed [(18)F]Galacto-RGD, a (18)F-labeled glycosylated αvÎČ3 antagonist, allowing monitoring of αvÎČ3 expression with positron emission tomography (PET). METHODS AND FINDINGS: Here we show by quantitative analysis of images resulting from a small-animal PET scanner that uptake of [(18)F]Galacto-RGD in the tumor correlates with αvÎČ3 expression subsequently determined by Western blot analyses. Moreover, using the A431 human squamous cell carcinoma model we demonstrate that this approach is sensitive enough to visualize αvÎČ3 expression resulting exclusively from the tumor vasculature. Most important, this study shows, that [(18)F]Galacto-RGD with PET enables noninvasive quantitative assessment of the αvÎČ3 expression pattern on tumor and endothelial cells in patients with malignant tumors. CONCLUSIONS: Molecular imaging with [(18)F]Galacto-RGD and PET can provide important information for planning and monitoring anti-angiogenic therapies targeting the αvÎČ3 integrins and can reveal the involvement and role of this integrin in metastatic and angiogenic processes in various diseases

    The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode as Deflagrations?

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    We present extensive u'g'r'i'BVRIYJHKs photometry and optical spectroscopy of SN 2005hk. These data reveal that SN 2005hk was nearly identical in its observed properties to SN 2002cx, which has been called ``the most peculiar known type Ia supernova.'' Both supernovae exhibited high ionization SN 1991T-like pre-maximum spectra, yet low peak luminosities like SN 1991bg. The spectra reveal that SN 2005hk, like SN 2002cx, exhibited expansion velocities that were roughly half those of typical type Ia supernovae. The R and I light curves of both supernovae were also peculiar in not displaying the secondary maximum observed for normal type Ia supernovae. Our YJH photometry of SN 2005hk reveals the same peculiarity in the near-infrared. By combining our optical and near-infrared photometry of SN 2005hk with published ultraviolet light curves obtained with the Swift satellite, we are able to construct a bolometric light curve from ~10 days before to ~60 days after B maximum. The shape and unusually low peak luminosity of this light curve, plus the low expansion velocities and absence of a secondary maximum at red and near-infrared wavelengths, are all in reasonable agreement with model calculations of a 3D deflagration which produces ~0.25 M_sun of 56Ni.Comment: Accepted by PASP, to appear in April 2007 issue, 63 pages, 16 figures, 11 table

    The Carnegie Supernova Project: First Near-Infrared Hubble Diagram to z~0.7

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    The Carnegie Supernova Project (CSP) is designed to measure the luminosity distance for Type Ia supernovae (SNe Ia) as a function of redshift, and to set observational constraints on the dark energy contribution to the total energy content of the Universe. The CSP differs from other projects to date in its goal of providing an I-band {rest-frame} Hubble diagram. Here we present the first results from near-infrared (NIR) observations obtained using the Magellan Baade telescope for SNe Ia with 0.1 < z < 0.7. We combine these results with those from the low-redshift CSP at z <0.1 (Folatelli et al. 2009). We present light curves and an I-band Hubble diagram for this first sample of 35 SNe Ia and we compare these data to 21 new SNe Ia at low redshift. These data support the conclusion that the expansion of the Universe is accelerating. When combined with independent results from baryon acoustic oscillations (Eisenstein et al. 2005), these data yield Omega_m = 0.27 +/- 0.0 (statistical), and Omega_DE = 0.76 +/- 0.13 (statistical) +/- 0.09 (systematic), for the matter and dark energy densities, respectively. If we parameterize the data in terms of an equation of state, w, assume a flat geometry, and combine with baryon acoustic oscillations, we find that w = -1.05 +/- 0.13 (statistical) +/- 0.09 (systematic). The largest source of systematic uncertainty on w arises from uncertainties in the photometric calibration, signaling the importance of securing more accurate photometric calibrations for future supernova cosmology programs. Finally, we conclude that either the dust affecting the luminosities of SNe Ia has a different extinction law (R_V = 1.8) than that in the Milky Way (where R_V = 3.1), or that there is an additional intrinsic color term with luminosity for SNe Ia independent of the decline rate.Comment: 44 pages, 23 figures, 9 tables; Accepted for publication in the Astrophysical Journa

    Prognostic Markers of DNA Methylation and Next-Generation Sequencing in Progressive Glioblastoma from the EORTC-26101 Trial

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    PURPOSE: The EORTC-26101 study was a randomized phase II and III clinical trial of bevacizumab in combination with lomustine versus lomustine alone in progressive glioblastoma. Other than for progression-free survival (PFS), there was no benefit from addition of bevacizumab for overall survival (OS). However, molecular data allow for the rare opportunity to assess prognostic biomarkers from primary surgery for their impact in progressive glioblastoma. EXPERIMENTAL DESIGN: We analyzed DNA methylation array data and panel sequencing from 170 genes of 380 tumor samples of the EORTC-26101 study. These patients were comparable with the overall study cohort in regard to baseline characteristics, study treatment, and survival.RESULTS: Of patients' samples, 295/380 (78%) were classified into one of the main glioblastoma groups, receptor tyrosine kinase (RTK)1, RTK2 and mesenchymal. There were 10 patients (2.6%) with isocitrate dehydrogenase mutant tumors in the biomarker cohort. Patients with RTK1 and RTK2 classified tumors had lower median OS compared with mesenchymal (7.6 vs. 9.2 vs. 10.5 months). O6-methylguanine DNA-methyltransferase (MGMT) promoter methylation was prognostic for PFS and OS. Neurofibromin (NF)1 mutations were predictive of response to bevacizumab treatment.CONCLUSIONS: Thorough molecular classification is important for brain tumor clinical trial inclusion and evaluation. MGMT promoter methylation and RTK1 classifier assignment were prognostic in progressive glioblastoma. NF1 mutation may be a predictive biomarker for bevacizumab treatment.</p
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