5,879 research outputs found

    Hemmschwellen und Ermöglichungsschwellen. Zur Operation der Verschiebung in Zwangsneurose und Perversion

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    Die Schwelle dient der Literatur wie der Philosophie nicht selten als Me­tapher. Allerdings ist dabei eine bestimmte Vorstellung von der Schwelle vorherrschend . nämlich die einer Zäsur in Raum und Zeit. In diesem Sinn kann von .Schwellenzauber. und .Schwellenerfahrungen. gespro­chen werden, lassen bestimmte Situationen sich als .Passagen., als Über­gänge von einem Zustand in einen anderen deuten oder erfahren (siehe dazu VanGennep 1909, Menninghaus 1986). \ud Dabei geht der Gebrauch der Metapher oft noch über den bildlichen Sinn hinaus . etwa, wenn im Zusammenhang der Kunst- und Kultur­vermittlung davon die Rede ist, daß ein an ein Museum angegliedertes Café die ganze Institution zu einer niedrigschwelligen mache. Hier schwillt die Schwelle gleichsam zu etwas an, was sie gar nicht ist, näm­lich zu etwas, das durch seine Höhe dem Überqueren Widerstand entge­gensetzt sie wird also zur Barriere, geradezu zu einer Hürde. Immerhin hat dieses Anwachsen der Schwelle zu einem nicht mehr bloß symboli­schen, Schwellenangst erzeugenden, sondern auch physischen, Anstren­gung und Sprungkraft erfordernden Hindernis auch wieder Grenzen. Eine Barrikade ist die Schwelle in diesem Sinn nie, es erschiene also lächer­lich, etwa von der Freiheit auf den Schwellen zu sprechen

    High-affinity binding sites involved in the import of porin into mitochondria

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    The specific recognition by mitochondria of the precursor of porin and the insertion into the outer membrane were studied with a radiolabeled water-soluble form of porin derived from the mature protein. High-affinity binding sites had a number of 5-10 pmol/mg mitochondrial protein and a ka of 1-5 X 10(8) M-1. Binding was abolished after trypsin pretreatment of mitochondria indicating that binding sites were of protein-aceous nature. Specifically bound porin could be extracted at alkaline pH but not by high salt and was protected against low concentrations of proteinase K. It could be chased to a highly protease resistant form corresponding to mature porin. High-affinity binding sites could be extracted from mitochondria with detergent and reconstituted in asolectin-ergosterol liposomes. Water-soluble porin competed for the specific binding and import of the precursor of the ADP/ATP carrier, an inner membrane protein. We suggest that (i) binding of precursors to proteinaceous receptors serves as an initial step for recognition, (ii) the receptor for porin may also be involved in the import of precursors of inner membrane proteins, and (iii) interaction with the receptor triggers partial insertion of the precursor into the outer membrane

    Mitochondrial protein import

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    Proteolytic degradation of receptor sites on the mitochondrial surface strongly reduces the efficiency of mitochondrial protein import. The remaining residual import still involves basic mechanisms of protein import, including: insertion of precursors into the outer membrane, requirement for ATP and a membrane potential, and translocation through contact sites between both membranes. The import of a chloroplast protein into isolated mitochondria which occurs with a low rate is not inhibited by a protease-pretreatment of mitochondria, indicating that this precursor only follows the bypass pathway. The low efficiency of bypass import suggests that this unspecific import does not disturb the uniqueness of mitochondrial protein composition. We conclude that mitochondrial protein import involves a series of steps in which receptor sites appear to be responsible for the specificity of protein uptake

    On the Role of Mechanics in Chronic Lung Disease.

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    Progressive airflow obstruction is a classical hallmark of chronic lung disease, affecting more than one fourth of the adult population. As the disease progresses, the inner layer of the airway wall grows, folds inwards, and narrows the lumen. The critical failure conditions for airway folding have been studied intensely for idealized circular cross-sections. However, the role of airway branching during this process is unknown. Here, we show that the geometry of the bronchial tree plays a crucial role in chronic airway obstruction and that critical failure conditions vary significantly along a branching airway segment. We perform systematic parametric studies for varying airway cross-sections using a computational model for mucosal thickening based on the theory of finite growth. Our simulations indicate that smaller airways are at a higher risk of narrowing than larger airways and that regions away from a branch narrow more drastically than regions close to a branch. These results agree with clinical observations and could help explain the underlying mechanisms of progressive airway obstruction. Understanding growth-induced instabilities in constrained geometries has immediate biomedical applications beyond asthma and chronic bronchitis in the diagnostics and treatment of chronic gastritis, obstructive sleep apnea and breast cancer

    The new protectionism and the limits of structural adjustment

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    However sharp the clash between the industrial countries' notions of a world economic order and those of the developing countries, one point is gaining increasing importance for both camps: the fight against spreading protectionism. Rising import barriers in the North restrict the developing countries opportunities to increase their foreign currency earnings, to come to grips with their debt problems and to push ahead with industrial development. Those concerned with economic policy in the North fear an escalation of trade discrimination that would gradually neutralise the allocative function of the market, hamper recovery from the present recession, encourage inflation and lead to the inefficient organisation of production throughout the world. Why is protectionism so difficult to halt in spite of the unanimous condemnation of it

    Marija Stambolieva, Stefan Dehnert (eds), Welfare States in Transition: 20 Years After the Yugoslav Welfare Model, Friedrich-Ebert-Stiftung, Sofia 2011

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    Are the western welfare states still competitive?

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    Is there a contradiction between international competitiveness and the central principles of the welfare state? The following article examines both the negative and the positive ways in which welfare statism can affect a country’s ability to compete on international markets

    Economic Policy within a European Monetary Union

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    A European Monetary Union (EMU) and the complete transfer of the responsibility for monetary policy to a European central bank are no longer utopian ideas, but a politically highly relevant possibility. The question how economic policy goals can be achieved within such a monetary union is therefore gaining in importance

    MOM19, an import receptor for mitochondrial precursor proteins

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    We have identified a 19 kd protein of the mitochondrial outer membrane (MOM19). Monospecific IgG and Fab fragments directed against MOM19 inhibit import of precursor proteins destined for the various mitochondrial subcompartments, including porin, cytochrome c1, Fe/S protein, F0 ATPase subunit 9, and F1 ATPase subunit β. Inhibition occurs at the level of high affinity binding of precursors to mitochondria. Consistent with previous functional studies that suggested the existence of distinct import sites for ADP/ATP carrier and cytochrome c, we find that import of those precursors is not inhibited. We conclude that MOM19 is identical to, or closely associated with, a specific mitochondrial import receptor
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