1,096 research outputs found

    Hysteretic vortex matching effects in high-TcT_c superconductors with nanoscale periodic pinning landscapes fabricated by He ion beam projection technique

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    Square arrays of sub-micrometer columnar defects in thin YBa2_{2}Cu3_{3}O7δ_{7-\delta} (YBCO) films with spacings down to 300 nm have been fabricated by a He ion beam projection technique. Pronounced peaks in the critical current and corresponding minima in the resistance demonstrate the commensurate arrangement of flux quanta with the artificial pinning landscape, despite the strong intrinsic pinning in epitaxial YBCO films. Whereas these vortex matching signatures are exactly at predicted values in field-cooled experiments, they are displaced in zero-field cooled, magnetic-field ramped experiments, conserving the equidistance of the matching peaks and minima. These observations reveal an unconventional critical state in a cuprate superconductor with an artificial, periodic pinning array. The long-term stability of such out-of-equilibrium vortex arrangements paves the way for electronic applications employing fluxons.Comment: 9 pages, 6 figures, to be published in Physical Review Applie

    Methylation Status of Imprinted Genes and Repetitive Elements in Sperm DNA from Infertile Males

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    Stochastic, environmentally and/or genetically induced disturbances in the genome-wide epigenetic reprogramming processes during male germ-cell development may contribute to male infertility. To test this hypothesis, we have studied the methylation levels of 2 paternally (H19 and GTL2) and 5 maternally methylated (LIT1, MEST, NESPAS, PEG3, and SNRPN) imprinted genes, as well as of ALU and LINE1 repetitive elements in 141 sperm samples, which were used for assisted reproductive technologies (ART), including 106 couples with strictly male-factor or combined male and female infertility and 28 couples with strictly female-factor infertility. Aberrant methylation imprints showed a significant association with abnormal semen parameters, but did not seem to influence ART outcome. Repeat methylation also differed significantly between sperm samples from infertile and presumably fertile males. However, in contrast to imprinted genes, ALU methylation had a significant impact on pregnancy and live-birth rate in couples with male-factor or combined infertility. ALU methylation was significantly high-er in sperm samples leading to pregnancy and live-birth than in those that did not. Sperm samples leading to abortions showed significantly lower ALU methylation levels than those leading to the birth of a baby. Copyright (C) 2011 S. Karger AG, Base

    High-Level Expression of Various Apolipoprotein (a) Isoforms by "Transferrinfection". The Role of Kringle IV Sequences in the Extracellular Association with Low-Density Lipoprotein

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    Characterization of the assembly of lipoprotein(a) [Lp(a)] is of fundamental importance to understanding the biosynthesis and metabolism of this atherogenic lipoprotein. Since no established cell lines exist that express Lp(a) or apolipoprotein(a) [apo(a)], a "transferrinfection" system for apo(a) was developed utilizing adenovirus receptor- and transferrin receptor-mediated DNA uptake into cells. Using this method, different apo(a) cDNA constructions of variable length, due to the presence of 3, 5, 7, 9, 15, or 18 internal kringle IV sequences, were expressed in cos-7 cells or CHO cells. All constructions contained kringle IV-36, which includes the only unpaired cysteine residue (Cys-4057) in apo(a). r-Apo(a) was synthesized as a precursor and secreted as mature apolipoprotein into the medium. When medium containing r-apo(a) with 9, 15, or 18 kringle IV repeats was mixed with normal human plasma LDL, stable complexes formed that had a bouyant density typical of Lp(a). Association was substantially decreased if Cys-4057 on r-apo(a) was replaced by Arg by site-directed mutagenesis or if Cys-4057 was chemically modified. Lack of association was also observed with r-apo(a) containing only 3, 5, or 7 kringle IV repeats without "unique kringle IV sequences", although Cys-4057 was present in all of these constructions. Synthesis and secretion of r-apo(a) was not dependent on its sialic acid content. r-Apo(a) was expressed even more efficiently in sialylation-defective CHO cells than in wild-type CHO cells. In transfected CHO cells defective in the addition of N-acetylglucosamine, apo(a) secretion was found to be decreased by 50%. Extracellular association with LDL was not affected by the carbohydrate moiety of r-apo(a), indicating a protein-protein interaction between r-apo(a) and apoB. These results show that, besides kringle IV-36, other kringle IV sequences are necessary for the extracellular association of r-apo(a) with LDL. Changes in the carbohydrate moiety of apo(a), however, do not affect complex formation

    Stability of Terrestrial Planets in the Habitable Zone of Gl 777 A, HD 72659, Gl 614, 47 Uma and HD 4208

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    We have undertaken a thorough dynamical investigation of five extrasolar planetary systems using extensive numerical experiments. The systems Gl 777 A, HD 72659, Gl 614, 47 Uma and HD 4208 were examined concerning the question of whether they could host terrestrial like planets in their habitable zones (=HZ). First we investigated the mean motion resonances between fictitious terrestrial planets and the existing gas giants in these five extrasolar systems. Then a fine grid of initial conditions for a potential terrestrial planet within the HZ was chosen for each system, from which the stability of orbits was then assessed by direct integrations over a time interval of 1 million years. The computations were carried out using a Lie-series integration method with an adaptive step size control. This integration method achieves machine precision accuracy in a highly efficient and robust way, requiring no special adjustments when the orbits have large eccentricities. The stability of orbits was examined with a determination of the Renyi entropy, estimated from recurrence plots, and with a more straight forward method based on the maximum eccentricity achieved by the planet over the 1 million year integration. Additionally, the eccentricity is an indication of the habitability of a terrestrial planet in the HZ; any value of e>0.2 produces a significant temperature difference on a planet's surface between apoapse and periapse. The results for possible stable orbits for terrestrial planets in habitable zones for the five systems are summarized as follows: for Gl 777 A nearly the entire HZ is stable, for 47 Uma, HD 72659 and HD 4208 terrestrial planets can survive for a sufficiently long time, while for Gl 614 our results exclude terrestrial planets moving in stable orbits within the HZ.Comment: 14 pages, 18 figures submitted to A&

    Negotiating care in the context of Finnish and Italian elder care policies

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    Negotiation is an integral part of all elder care, which by definition involves a relation between at least two people. In this article we analyse negotiations concerning elder care in the context of Finnish and Italian elder care policies. At the macro level negotiations on elder care are shaped by elder care policies and at the micro level by individual skills and resources. Our focus is on the negotiations on eligibility that take place when elders attempt to access care. The data consist of qualitative interviews with Finnish and Italian elders in need of care. The analysis of individual experiences of care negotiations reflects the implementation of elder care policies. The results indicate that the most negotiated eligibility criteria when seeking access to elder care are need, money and social relations. These criteria are negotiated when seeking eligibility to different sources of care: informal care, grey market, market-based, non-profit and public services. In Italy, negotiation is particularly crucial when accessing grey market care. Cash as the main Italian elder care policy tool tends to enhance the role of and need for negotiation. In Finland, a greater part of elder care is provided by the public sector and therefore the process of negotiation is more standardized than in Italy

    Timing Analysis using the MARTE Profile in the Design of Rail Automation Systems

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    International audienceFor dependable systems as in the railway domain the timing behaviour is considered part of the functional correctness. Thus timing requirements have to be traced and refined through the system and software development phases and validation and verification efforts have to address the timing as well as the pure input/output behaviour. We show how timing can be handled in a UML or SysML based approach to the development of software-intensive railway systems by using the new MARTE profile. Thereby timing becomes fully integrated in the chain of system and software models and may benefit from tool support. Moreover, automated timing analysis may be employed via model transformations which enables the exploration of timing-related issues in various design phases

    Österreichisches Projekt Grundlagen zur Züchtung, Vermehrung und Sorten-/Saatgutprüfung für den Biolandbau: Ergebnisübersicht

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    In the Austrian research project “Basic principles for breeding, multiplication and variety testing for organic agriculture” (from 2004 until 2008) novel methods for the assessment of the suitability of seed and cultivars for organic farming were developed and evaluated by an interdisciplinary co-operation of researchers, breeders and variety testers. Organic farming requires specific combinations of crop plant characters, especially seed health and resistance against seed-borne diseases. Another crucial feature is the competitive ability against weeds. Early development was found to significantly increase the competitiveness of different crop plants. Genotypic variation in characters necessary for an efficient utilisation of below-ground resources was also investigated, e.g. interrelations between root development and drought stress tolerance and between mycorrhiza formation and nutrient use efficiency. Based on the results obtained in various cultivar trials, it can be concluded that genotypes suitable for organic growing conditions may be pre-selected from early breeding material of conventional breeding programmes. The selected breeding material must subsequently be rigorously tested on organically managed fields starting from the first yield trials at the latest. The project results were communicated to farmers and advisors during field days and excursions. They will be applied in the breeding of new cultivars

    SREBP-2/PNPLA8 axis improves non-alcoholic fatty liver disease through activation of autophagy

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    Dysregulated autophagy is associated with steatosis and non-alcoholic fatty liver disease (NAFLD), however the mechanisms connecting them remain poorly understand. Here, we show that co-administration of lovastatin and ezetimibe (L/E) significantly reverses hepatic triglyceride accumulation concomitant with an increase in SREBP-2 driven autophagy in mice fed a high-fat diet (HFD). We further show that the statin mediated increase in SREBP-2 directly activates expression of patatin-like phospholipase domain-containing enzyme 8 (PNPLA8) gene, and PNPLA8 associates with autophagosomes and is associated with a decrease in cellular triglyceride. Moreover, we show that over-expression of PNPLA8 dramatically decreases hepatic steatosis through increased autophagy in hepatocytes of HFD-fed mice. Live-cell imaging analyses also reveal that PNPLA8 dynamically interacts with LC3 and we suggest that the SREBP-2/PNPLA8 axis represents a novel regulatory mechanism for lipid homeostasis. These data provide a possible mechanism for the reported beneficial effects of statins for decreasing hepatic triglyceride levels in NAFLD patients.ope

    Macrophage Glucose-6-Phosphate Dehydrogenase Stimulates Proinflammatory Responses with Oxidative Stress

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    Glucose-6-phosphate dehydrogenase (G6PD) is a key enzyme that regulates cellular redox potential. In this study, we demonstrate that macrophage G6PD plays an important role in the modulation of proinflammatory responses and oxidative stress. The G6PD levels in macrophages in the adipose tissue of obese animals were elevated, and G6PD mRNA levels positively correlated with those of proinflammatory genes. Lipopolysaccharide (LPS) and free fatty acids, which initiate proinflammatory signals, stimulated macrophage G6PD. Overexpression of macrophage G6PD potentiated the expression of proinflammatory and prooxidative genes responsible for the aggravation of insulin sensitivity in adipocytes. In contrast, when macrophage G6PD was inhibited or suppressed via chemical inhibitors or small interfering RNA (siRNA), respectively, basal and LPS-induced proinflammatory gene expression was attenuated. Furthermore, macrophage G6PD increased activation of the p38 mitogen-activated protein kinase (MAPK) and NF-??B pathways, which may lead to a vicious cycle of oxidative stress and proinflammatory cascade. Together, these data suggest that an abnormal increase of G6PD in macrophages promotes oxidative stress and inflammatory responses in the adipose tissue of obese animals.open5
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