66 research outputs found

    Optical spectroscopy of Yb3+ centers in BaMgF4 ferroelectric crystal

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    The following article appeared in Journal of Applied Physics 110.6 (2011): 063102 and may be found at http://scitation.aip.org/content/aip/journal/jap/110/6/10.1063/1.3638040We report on the optical characterization of Yb3+ doped BaMgF4+ nonlinear fluoride crystal grown by the Czochralski technique. Low temperature absorption spectroscopy reveals that Yb3+ incorporates into the matrix at four well differentiated centers. High resolution site selective experiments have been performed to determine the energy level schemes associated with the major Yb3+ centers detected in the system. The fluorescence decay times recorded at 10 K under selective excitation are analyzed for each Yb3+ center. The spectroscopic behavior of the codoped Yb3+:Na+:BaMgF4+ system has been also investigated. Codoping with Na+ eliminates two Yb3+ centers present in the singly doped Yb3+:BaMgF 4+ crystal. The charge compensation mechanisms and site location for Yb3+ in the fluoride matrix are discussedThis work has been supported by Spanish MICINN under Contract Nos. MAT2010-17443 and MAT2009-06580, Comunidad de Madrid under Grant No. PHAMA S2009/MAT-1756 and Universidad Autónoma de Madrid under Contract No. CCG10-UAM/MAT-5290

    Local environment of optically active Nd3 + ions in the ultratransparent BaMgF 4 ferroelectric crystal

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    A comprehensive study of the site location of Nd3 + ions in the BaMgF 4 ultratransparent ferroelectric crystal is presented. By combining different low-temperature optical spectroscopies and electron paramagnetic resonance, the crystal field energy levels of Nd3 + ions and the gyromagnetic factors are experimentally determined. These results are employed to perform the crystal field analysis of Nd3 + ions considering a Cs point symmetry. The crystal field calculation yields a small root-mean-square deviation of 18 cm -1 and reveals a large crystal field strength (621 cm -1), verifying the assignment of the Ba2 + cationic site as the location for Nd3 + ions in this fluoride host. The results suggest a slight displacement of Nd3 + from the barium regular site with a rearrangement of the fluorine ions around it. The work gives a deep insight into the properties of the Nd3 +-doped BaMgF 4 crystal, a ferroelectric widely ultra-transparent material with potential applications as optical device operating in the Vacuum Ultraviolet-Ultraviolet and midinfrared spectral regionsThis work has been supported by the Spanish Ministry of Science under projects MAT2010-17443, MAT2010-21270-C04-02, Consolider-Ingenio MALTA CSD 2007-0045, and Comunidad Autonoma de Madrid under Grant 2009/MAT-175

    Modeling Core Metabolism in Cancer Cells: Surveying the Topology Underlying the Warburg Effect

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    BACKGROUND: Alterations on glucose consumption and biosynthetic activity of amino acids, lipids and nucleotides are metabolic changes for sustaining cell proliferation in cancer cells. Irrevocable evidence of this fact is the Warburg effect which establishes that cancer cells prefers glycolysis over oxidative phosphorylation to generate ATP. Regulatory action over metabolic enzymes has opened a new window for designing more effective anti-cancer treatments. This enterprise is not trivial and the development of computational models that contribute to identifying potential enzymes for breaking the robustness of cancer cells is a priority. METHODOLOGY/PRINCIPAL FINDINGS: This work presents a constraint-base modeling of the most experimentally studied metabolic pathways supporting cancer cells: glycolysis, TCA cycle, pentose phosphate, glutaminolysis and oxidative phosphorylation. To evaluate its predictive capacities, a growth kinetics study for Hela cell lines was accomplished and qualitatively compared with in silico predictions. Furthermore, based on pure computational criteria, we concluded that a set of enzymes (such as lactate dehydrogenase and pyruvate dehydrogenase) perform a pivotal role in cancer cell growth, findings supported by an experimental counterpart. CONCLUSIONS/SIGNIFICANCE: Alterations on metabolic activity are crucial to initiate and sustain cancer phenotype. In this work, we analyzed the phenotype capacities emerged from a constructed metabolic network conformed by the most experimentally studied pathways sustaining cancer cell growth. Remarkably, in silico model was able to resemble the physiological conditions in cancer cells and successfully identified some enzymes currently studied by its therapeutic effect. Overall, we supplied evidence that constraint-based modeling constitutes a promising computational platform to: 1) integrate high throughput technology and establish a crosstalk between experimental validation and in silico prediction in cancer cell phenotype; 2) explore the fundamental metabolic mechanism that confers robustness in cancer; and 3) suggest new metabolic targets for anticancer treatments. All these issues being central to explore cancer cell metabolism from a systems biology perspective

    Characterisation and expression of calpain family members in relation to nutritional status, diet composition and flesh texture in gilthead sea bream (Sparus aurata).

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    Calpains are non-lysosomal calcium-activated neutral proteases involved in a wide range of cellular processes including muscle proteolysis linked to post-mortem flesh softening. The aims of this study were (a) to characterise several members of the calpain system in gilthead sea bream and (b) to examine their expression in relation to nutritional status and muscle tenderisation. We identified the complete open reading frame of gilthead sea bream calpains1-3, sacapn1, sacapn2, sacapn3, and two paralogs of the calpain small subunit1, sacapns1a and sacapns1b. Proteins showed 63-90% sequence identity compared with sequences from mammals and other teleost fishes, and the characteristic domain structure of vertebrate calpains. Transcripts of sacapn1, sacapn2, sacapns1a and sacapns1b had a wide tissue distribution, whereas sacapn3 was almost exclusively detected in skeletal muscle. Next, we assessed transcript expression in skeletal muscle following alteration of nutritional status by (a) fasting and re-feeding or (b) feeding four experimental diets with different carbohydrate-to-protein ratios. Fasting significantly reduced plasma glucose and increased free fatty acids and triglycerides, together with a significant increase in sacapns1b expression. Following 7 days of re-feeding, plasma parameters returned to fed values and sacapn1, sacapn2, sacapns1a and sacapns1b expression was significantly reduced. Furthermore, an increase in dietary carbohydrate content (11 to 39%) diminished growth but increased muscle texture, which showed a significant correlation with decreased sacapn1 and sacapns1a expression, whilst the other calpains remained unaffected. This study has demonstrated that calpain expression is modulated by nutritional status and diet composition in gilthead sea bream, and that the expression of several calpain members is correlated with muscle texture, indicating their potential use as molecular markers for flesh quality in aquaculture production

    A comprehensive molecular study on Coffin-Siris and Nicolaides-Baraitser syndromes identifies a broad molecular and clinical spectrum converging on altered chromatin remodeling

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    Chromatin remodeling complexes are known to modify chemical marks on histones or to induce conformational changes in the chromatin in order to regulate transcription. De novo dominant mutations in different members of the SWI/SNF chromatin remodeling complex have recently been described in individuals with Coffin-Siris (CSS) and Nicolaides-Baraitser (NCBRS) syndromes. Using a combination of whole-exome sequencing, NGS-based sequencing of 23 SWI/SNF complex genes, and molecular karyotyping in 46 previously undescribed individuals with CSS and NCBRS, we identified a de novo 1-bp deletion (c.677delG, p.Gly226Glufs*53) and a de novo missense mutation (c.914G>T, p.Cys305Phe) in PHF6 in two individuals diagnosed with CSS. PHF6 interacts with the nucleosome remodeling and deacetylation (NuRD) complex implicating dysfunction of a second chromatin remodeling complex in the pathogenesis of CSS-like phenotypes. Altogether, we identified mutations in 60% of the studied individuals (28/46), located in the genes ARID1A, ARID1B, SMARCB1, SMARCE1, SMARCA2, and PHF6. We show that mutations in ARID1B are the main cause of CSS, accounting for 76% of identified mutations. ARID1B and SMARCB1 mutations were also found in individuals with the initial diagnosis of NCBRS. These individuals apparently belong to a small subset who display an intermediate CSS/NCBRS phenotype. Our proposed genotype-phenotype correlations are important for molecular screening strategie

    The Authoritarian Past and South European Democracies: an introduction

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    It is the object of the contributors to this volume to compare how Southern European democracies have reacted to past authoritarian regimes. This introduction has three sections. In the first we seek to frame the concepts of authoritarian legacies, transitional justice and the politics of the past as they are applied here. In the second we analyse the forms of transitional justice that were present during the processes of democratisation in Southern Europe, while the third section presents an outline of the volume and of the contributions made by its authors

    EFECTO DE LOS FOSFOLÍPIDOS MARINOS SOBRE BIOMARCADORES NUTRICIONALES Y DE ESTRÉS FISIOLÓGICO DE LAS PARALARVAS DEL PULPO COMÚN (OCTOPUS VULGARIS) BAJO CONDICIONES DE CULTIVO ESTANDARIZADAS EN TRES CENTROS

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    El efecto del enriquecimiento de la Artemia con fosfolípidos marinos (LC60), sobre el crecimiento, la supervivencia y los biomarcadores de condición nutricional (ARN/ADN) y de estrés fisiológico (proteínas de estrés (HSP70), enzimas antioxidantes y peroxidación lipídica) en paralarvas cultivadas de pulpo común (Octopus vulgaris) se evaluó bajo un protocolo estandarizado en tres centros. Las paralarvas recién eclosionadas mostraron diferencias significativas entre centros en peso seco y en la mayor parte de los biomarcadores analizados. Por el contario, en paralarvas cultivadas de 15 días, se encontraron diferencias significativas debidas a la dieta, presentando un incremento en la tasa de crecimiento específica (TCE) en el grupo alimentado con Artemia enriquecida con LC60 y mayores niveles de actividad GPX T y GR. Sin embargo, la dieta no tuvo efecto en la supervivencia de las paralarvas. Los biomarcadores de condición nutricional y de estrés fisiológicos presentaron diferencias entre los centros. Los resultados indican que el uso de fosfolípidos marinos como enriquecimiento de Artemia mejora el crecimiento de las paralarvas, si bien no se observa un efecto positivo de dicho tratamiento sobre la supervivencia de las mismas

    State of the climate in 2017

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    In 2017, the dominant greenhouse gases released into Earth's atmosphere-carbon dioxide, methane, and nitrous oxide-reached new record highs. The annual global average carbon dioxide concentration at Earth's surface for 2017 was 405.0 ± 0.1 ppm, 2.2 ppm greater than for 2016 and the highest in the modern atmospheric measurement record and in ice core records dating back as far as 800 000 years. The global growth rate of CO2 has nearly quadrupled since the early 1960s. With ENSO-neutral conditions present in the central and eastern equatorial Pacific Ocean during most of the year and weak La Niña conditions notable at the start and end, the global temperature across land and ocean surfaces ranked as the second or third highest, depending on the dataset, since records began in the mid-to-late 1800s. Notably, it was the warmest non-El Niño year in the instrumental record. Above Earth's surface, the annual lower tropospheric temperature was also either second or third highest according to all datasets analyzed. The lower stratospheric temperature was about 0.2°C higher than the record cold temperature of 2016 according to most of the in situ and satellite datasets. Several countries, including Argentina, Uruguay, Spain, and Bulgaria, reported record high annual temperatures. Mexico broke its annual record for the fourth consecutive year. On 27 January, the temperature reached 43.4°C at Puerto Madryn, Argentina-the highest temperature recorded so far south (43°S) anywhere in the world. On 28 May in Turbat, western Pakistan, the high of 53.5°C tied Pakistan's all-time highest temperature and became the world-record highest temperature for May. In the Arctic, the 2017 land surface temperature was 1.6°C above the 1981-2010 average, the second highest since the record began in 1900, behind only 2016. The five highest annual Arctic temperatures have all occurred since 2007. Exceptionally high temperatures were observed in the permafrost across the Arctic, with record values reported in much of Alaska and northwestern Canada. In August, high sea surface temperature (SST) records were broken for the Chukchi Sea, with some regions as warm as +11°C, or 3° to 4°C warmer than the longterm mean (1982-present). According to paleoclimate studies, today's abnormally warm Arctic air and SSTs have not been observed in the last 2000 years. The increasing temperatures have led to decreasing Arctic sea ice extent and thickness. On 7 March, sea ice extent at the end of the growth season saw its lowest maximum in the 37-year satellite record, covering 8% less area than the 1981-2010 average. The Arctic sea ice minimum on 13 September was the eighth lowest on record and covered 25% less area than the long-term mean. Preliminary data indicate that glaciers across the world lost mass for the 38th consecutive year on record; the declines are remarkably consistent from region to region. Cumulatively since 1980, this loss is equivalent to slicing 22 meters off the top of the average glacier. Antarctic sea ice extent remained below average for all of 2017, with record lows during the first four months. Over the continent, the austral summer seasonal melt extent and melt index were the second highest since 2005, mostly due to strong positive anomalies of air temperature over most of the West Antarctic coast. In contrast, the East Antarctic Plateau saw record low mean temperatures in March. The year was also distinguished by the second smallest Antarctic ozone hole observed since 1988. Across the global oceans, the overall long-term SST warming trend remained strong. Although SST cooled slightly from 2016 to 2017, the last three years produced the three highest annual values observed; these high anomalies have been associated with widespread coral bleaching. The most recent global coral bleaching lasted three full years, June 2014 to May 2017, and was the longest, most widespread, and almost certainly most destructive such event on record. Global integrals of 0-700-m and 0-2000-m ocean heat content reached record highs in 2017, and global mean sea level during the year became the highest annual average in the 25-year satellite altimetry record, rising to 77 mm above the 1993 average. In the tropics, 2017 saw 85 named tropical storms, slightly above the 1981-2010 average of 82. The North Atlantic basin was the only basin that featured an above-normal season, its seventh most active in the 164-year record. Three hurricanes in the basin were especially notable. Harvey produced record rainfall totals in areas of Texas and Louisiana, including a storm total of 1538.7 mm near Beaumont, Texas, which far exceeds the previous known U.S. tropical cyclone record of 1320.8 mm. Irma was the strongest tropical cyclone globally in 2017 and the strongest Atlantic hurricane outside of the Gulf of Mexico and Caribbean on record with maximum winds of 295 km h-1. Maria caused catastrophic destruction across the Caribbean Islands, including devastating wind damage and flooding across Puerto Rico. Elsewhere, the western North Pacific, South Indian, and Australian basins were all particularly quiet. Precipitation over global land areas in 2017 was clearly above the long-term average. Among noteworthy regional precipitation records in 2017, Russia reported its second wettest year on record (after 2013) and Norway experienced its sixth wettest year since records began in 1900. Across India, heavy rain and flood-related incidents during the monsoon season claimed around 800 lives. In August and September, above-normal precipitation triggered the most devastating floods in more than a decade in the Venezuelan states of Bolívar and Delta Amacuro. In Nigeria, heavy rain during August and September caused the Niger and Benue Rivers to overflow, bringing floods that displaced more than 100 000 people. Global fire activity was the lowest since at least 2003; however, high activity occurred in parts of North America, South America, and Europe, with an unusually long season in Spain and Portugal, which had their second and third driest years on record, respectively. Devastating fires impacted British Columbia, destroying 1.2 million hectares of timber, bush, and grassland, due in part to the region's driest summer on record. In the United States, an extreme western wildfire season burned over 4 million hectares; the total costs of $18 billion tripled the previous U.S. annual wildfire cost record set in 1991

    Coping with the Double Legacy of Authoritarianism and Revolution in Portuguese Democracy

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    Comparative research on democratisation suggests the political space for the immediate punishment of previous dictatorships depends on the type of transition and the correlative power-sharing and veto capacity of the political actors and institutions. This article argues that the type and diversity of transitional justice in Portugal's democratisation must be correlated not only with the absence of the veto capacity of former authoritarian elites and institutions, due to their collapse, but mainly with the cleavages opened by democratisation and military intervention in politics. We also argue that the nature of the transition is superimposed on the nature of the authoritarian regime and the extent of its legacy in the type of transitional justice, and that the transition's powerful dynamic served to constitute another legacy for the consolidation of democracy, strongly counterbalancing those of the authoritarian regime
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