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

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

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

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.

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

MOM19, an import receptor for mitochondrial precursor proteins

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

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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Exact symmetries in the velocity fluctuations of a hot Brownian swimmer

Symmetries constrain dynamics. We test this fundamental physical principle, experimentally and by molecular dynamics simulations, for a hot Janus swimmer operating far from thermal equilibrium. Our results establish scalar and vectorial steady-state fluctuation theorems and a thermodynamic uncertainty relation that link the fluctuating particle current to its entropy production at an effective temperature. A Markovian minimal model elucidates the underlying non-equilbrium physics.Comment: 5 pages, 3 figure

Import pathways of precursor proteins into mitochondria

The precursor of porin, a mitochondrial outer membrane protein, competes for the import of precursors destined for the three other mitochondrial compartments, including the Fe/S protein of the bc1- complex (intermembrane space), the ADP/ATP carrier (inner membrane), subunit 9 of the F0-ATPase (inner membrane), and subunit beta of the F1- ATPase (matrix). Competition occurs at the level of a common site at which precursors are inserted into the outer membrane. Protease- sensitive binding sites, which act before the common insertion site, appear to be responsible for the specificity and selectivity of mitochondrial protein uptake. We suggest that distinct receptor proteins on the mitochondrial surface specifically recognize precursor proteins and transfer them to a general insertion protein component (GIP) in the outer membrane. Beyond GIP, the import pathways diverge, either to the outer membrane or to translocation contact-sites, and then subsequently to the other mitochondrial compartments

Digital Marketing as a tool for tourism promotion: Destination Branding in Spain

Digital Marketing is the new reality when it comes to the promotion of tourist destinations. Nowadays, tourists are more demanding than ever as they expect personalized treatment throughout their entire experience. To face this challenge, Spain’s National Tourist Office (Tourspain) opts for a destination branding strategy. It is supported by the Spain brand and partially carried out through digital marketing channels. This paper provides a theoretical base of the main concepts of Digital Marketing and Destination Branding, followed by an evaluation of Tourspain’s effective marketing actions such as Social Media Marketing, international advertisement campaigns, and the official tourism portalUniversidad de Sevilla. Grado en Turism