Johannes Kepler University of Linz

About: Johannes Kepler University of Linz is a education organization based out in Linz, Oberösterreich, Austria. It is known for research contribution in the topics: Computer science & Thin film. The organization has 6605 authors who have published 19243 publications receiving 385667 citations.

Intrinsic Membrane Permeability to Small Molecules

Abstract: Spontaneous solute and solvent permeation through membranes is of vital importance to human life, be it gas exchange in red blood cells, metabolite excretion, drug/toxin uptake, or water homeostasis. Knowledge of the underlying molecular mechanisms is the sine qua non of every functional assignment to membrane transporters. The basis of our current solubility diffusion model was laid by Meyer and Overton. It correlates the solubility of a substance in an organic phase with its membrane permeability. Since then, a wide range of studies challenging this rule have appeared. Commonly, the discrepancies have their origin in ill-used measurement approaches, as we demonstrate on the example of membrane CO2 transport. On the basis of the insight that scanning electrochemical microscopy offered into solute concentration distributions in immediate membrane vicinity of planar membranes, we analyzed the interplay between chemical reactions and diffusion for solvent transport, weak acid permeation, and enzymatic reactions adjacent to membranes. We conclude that buffer reactions must also be considered in spectroscopic investigations of weak acid transport in vesicular suspensions. The evaluation of energetic contributions to membrane translocation of charged species demonstrates the compatibility of the resulting membrane current with the solubility diffusion model. A local partition coefficient that depends on membrane penetration depth governs spontaneous membrane translocation of both charged and uncharged molecules. It is determined not only by the solubility in an organic phase but also by other factors like cholesterol concentration and intrinsic electric membrane potentials.

How the sperm dominates the ovum — objectification by metaphor in the social representation of conception

Abstract: This investigation is about the use of metaphors in the everyday understanding of conception. It is argued that the analysis of the relationship between source and target domain in a metaphor used as an objectification device can help explain how social representations are acquired collectively and individually. We expect that in popular knowledge of conception the central metaphors and images relate to the subjects' everyday experience as social actors and sexual beings because social and sexual experience is pervasive and well-understood. In an experimental questionnaire study involving 169 subjects, it is shown as hypothesized that subjects prefer to compare the process of fertilization, i.e. the role and behaviour of sperms and ovum, with sexual and sex-role behaviour where the role of men is projected upon sperms and the role of women upon the ovum. This implies that sperms are seen not only as more active, but also as harder, stronger, and more dominant than the ovum. These effects are stronger, the more subjects personally subscribe to a more conservative sex-role orientation. In the discussion it is suggested that it is necessary to analyse the two intricately linked levels of objectification, the cognitive process of selecting specific images and the social process of the diffusion of popular knowledge, if we want to understand how common sense works.

Family and non-family succession in the Upper-Austrian farm sector.

Abstract: Using linked census data from 1980, 1985, and 1990 actual succession decisions of Upper-Austrian farm households are examined empirically Two types of succession are distinguished by inspecting the age of the farm operator and other household members in the consecutive census observations : “family succession” (succession by the farm operator’s child) and “non-family succession” (the farm is sold outside the family) Farm exits are considered as an additional category in the model Several characteristics of the farm and of the farm operator’s household are found to influence the succession decision significantly Model choice and specification issues are discussed