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: Thin film & Quantum dot. The organization has 6605 authors who have published 19243 publications receiving 385667 citations.

TCR–peptide–MHC interactions in situ show accelerated kinetics and increased affinity

Abstract: The use of a novel FRET-based imaging system provides an in situ view of the kinetics of T-cell receptor (TCR) binding to peptide MHC complexes in their natural environment, the immunological synapse. Previously the mater of how containment in this environment would affect the molecular interactions that drive cell–cell interactions has been a matter of speculation. Now that they have been measured, both expected effects (enhanced association rate due to optimal orientation) and unexpected (a very active cytoskeletal component destabilizing TCR binding) are revealed. This work is of relevance to T-cell immunology and to in cell–cell interactions more generally. T lymphocytes, which are an integral part of most adaptive immune responses, recognize foreign antigens through the binding of antigenic peptide–major histocompatibility complex (pMHC) molecules on other cells to specific T-cell antigen receptors (TCRs). Using single-molecule microscopy and fluorescence resonance energy transfer, the kinetics of TCR–pMHC binding are now measured in situ, revealing accelerated kinetics and increased affinity when compared with solution measurements. The recognition of foreign antigens by T lymphocytes is essential to most adaptive immune responses. It is driven by specific T-cell antigen receptors (TCRs) binding to antigenic peptide–major histocompatibility complex (pMHC) molecules on other cells1. If productive, these interactions promote the formation of an immunological synapse2,3. Here we show that synaptic TCR–pMHC binding dynamics differ significantly from TCR–pMHC binding in solution. We used single-molecule microscopy and fluorescence resonance energy transfer (FRET) between fluorescently tagged TCRs and their cognate pMHC ligands to measure the kinetics of TCR–pMHC binding in situ. When compared with solution measurements, the dissociation of this complex was increased significantly (4–12-fold). Disruption of actin polymers reversed this effect, indicating that cytoskeletal dynamics destabilize this interaction directly or indirectly. Nevertheless, TCR affinity for pMHC was significantly elevated as the result of a large (about 100-fold) increase in the association rate, a likely consequence of complementary molecular orientation and clustering. In helper T cells, the CD4 molecule has been proposed to bind cooperatively with the TCR to the same pMHC complex. However, CD4 blockade had no effect on the synaptic TCR affinity, nor did it destabilize TCR–pMHC complexes, indicating that the TCR binds pMHC independently of CD4.

Cultural variation of leadership prototypes across 22 European countries

Abstract: This study sets out to test the assumption that concepts of leadership differ as a function of cultural differences in Europe and to identify dimensions which describe differences in leadership concepts across European countries. Middle-level managers (N = 6052) from 22 European countries rated 112 questionnaire items containing descriptions of leadership traits and behaviours. For each attribute respondents rated how well it fits their concept of an outstanding business leader. The findings support the assumption that leadership concepts are culturally endorsed. Specifically, clusters of European countries which share similar cultural values according to prior cross-cultural research (Ronen & Shenkar, 1985), also share similar leadership concepts. The leadership prototypicality dimensions found are highly correlated with cultural dimensions reported in a comprehensive cross-cultural study of contemporary Europe (Smith, Dugan, & Trompenaars, 1996). The ordering of countries on the leadership dimensions is considered a useful tool with which to model differences between leadership concepts of different cultural origin in Europe. Practical implications for cross-cultural management, both in European and non-European settings, are discussed.

The Dynamic Capability View in Strategic Management: A Bibliometric Review

Abstract: The dynamic capability view (DCV) is one of the most vibrant approaches to strategic management. In this study, the extant literature published between 1994 and 2011 is analysed, using bibliometric methods in order to explore the scope of this approach and detect current research priorities. For this purpose, the method of bibliographic coupling is introduced in management research, which shifts the focus of analysis from past traditions to current trends. Several clusters of thematically related research are extracted from bibliographic networks, which represent interconnected yet distinct subfields of inquiry within the DCV. The core cluster of the current DCV, which visualizes this research field's nascent but fragile identity, focuses on learning and change capabilities and relates them to firm performance, thus merging aspects of organization theory and strategic management. In addition, several peripheral clusters of research are identified, which reflect a parallel process of differentiation in the overall field. Both trends, i.e. of integration and differentiation, attest to the emancipation of the DCV as a distinct approach to strategic management. However, the DCV still lacks consensual concepts that allow comparisons of empirical studies and advance the theoretical understanding of dynamic capabilities. In the light of the above, some implications of this analysis for further research are discussed.

Stretching Dielectric Elastomer Performance

Abstract: The idea that a solid material can deform when stimulated by electricity originated in the late-18th century with observations of ruptures in overcharged Leyden jars, the first electrical capacitors. In 1776, Italian scientist Alessandro Volta mentioned in a letter that Italian experimenter Felice Fontana had noted volume changes in the Leyden jar upon electrification ( 1 ), an observation that launched a new field of investigation—“deformable” materials affected by electricity. More than two centuries later, the concept of “electrically stretchable materials” is at the forefront of devising bioinspired robots, tactile and haptic interfaces, and adaptive optical systems ( 2 , 3 ).