Mechanochemical control of epidermal stem cell divisions by B-plexins

The precise spatiotemporal control of cell proliferation is key to the morphogenesis of epithelial tissues. Epithelial cell divisions lead to tissue crowding and local changes in force distribution, which in turn suppress the rate of cell divisions. However, the molecular mechanisms underlying this mechanical feedback are largely unclear. Here, we identify a critical requirement of B-plexin transmembrane receptors in the response to crowding-induced mechanical forces during embryonic skin development. Epidermal stem cells lacking B-plexins fail to sense mechanical compression, resulting in disinhibition of the transcriptional coactivator YAP, hyperproliferation, and tissue overgrowth. Mechanistically, we show that B-plexins mediate mechanoresponses to crowding through stabilization of adhesive cell junctions and lowering of cortical stiffness. Finally, we provide evidence that the B-plexin-dependent mechanochemical feedback is also pathophysiologically relevant to limit tumor growth in basal cell carcinoma, the most common type of skin cancer. Our data define a central role of B-plexins in mechanosensation to couple cell density and cell division in development and disease.Peer reviewe

Instructions for motor learning: Differential effects of internal vs external focus of attention

3

Production of highly ordered nanoporous alumina and its application in cell cultivation

Nanoporous alumina membranes were utilized as cell culture substrates. Two different anodization processes were applied in order to obtain highly ordered, self-supporting nanoporous alumina membranes. The resulting membranes exhibit uniform nanopores with constant diameters having aspect ratios (pore depth:pore diameter) larger than 1000. Tentative experiments evaluating the cellular interaction of a hepatoma cell line (HepG2) with the nanoporous alumina membranes will be described. Furthermore, cell proliferation as well as the adhesion behavior of the cells on the porous substrates was investigated. Scanning electron microscopy (SEM) and focused ion beam (FIB) technology were applied to examine the cell morphology. The experiments revealed that the nanoporous membranes can be used as cel l culture substrates and that they have no adverse effects on cell proliferation and cell viability. Besides, cells on membranes with pore diameters larger than 200 nm developed small cell extensions (filopodia) which penetrated into the nanopores

On a relation between particle size distribution and mixing layer height.

Ceilometers are applied to detect layering of the lower atmosphere continuously. This is necessary because not only wind speeds and directions but also atmospheric layering and especially the mixing layer height (MLH) influence exchange processes of ground level emissions. It will be discussed how the ceilometer monitoring information can be used to determine the MLH influence upon the particle size distribution (PSD) which is detected near the ground. The information about atmospheric layering is continuously monitored by uninterrupted remote sensing measurements with the Vaisala ceilometers LD40 and CL31 which are eye-safe commercial lidar systems. Special software for these ceilometers provides routine retrievals of lower atmosphere layering from vertical profiles of laser backscatter data. The meteorological data are collected by the air pollution monitoring station of the Bavarian State Agency of Environment (LfU) at the southern edge of Augsburg and at the airport at the northern edge of Augsburg by the German National Meteorological Service (DWD). PSD are measured at the aerosol measurement station in the centre of Augsburg by the Cooperative Health Research in the Region of Augsburg (KORA). The two intensive measurement periods during the winter 2006/2007 and 2007/2008 are studied. The weather situations are characterized, the meteorological influences upon air pollutant concentrations like wind speed and wind direction are studied and the correlations of ceilometer backscatter densities and MLH with PSD are determined

Adaptive READ. Lesen und Lernen - Vom Dokument zum Wissen. Band 3: Inhaltliche Strukturierung von Dokumenten

Die Strukturierung von nur in einer layoutierten Form vorliegenden Dokumente stellt für die zukünftige Informationsverarbeitung in Unternehmen eine zunehmend wichtige Aktivität und Herausforderung dar. Denn erst nach der, heute noch oft manuell zu geschehenden, Festlegung der logischen Struktur eines Dokuments können diese Zusatzinformationen beispielsweise zur Verbesserung der Recherche genutzt werden. In dem vorliegenden Band werden die Ergebnisse, die das Institut für Arbeitswissenschaft und Technologiemanagement (IAT) der Universität Stuttgart im Rahmen des Verbundprojekts »Adaptive READ« auf dem Gebiet der Informationsstrukturierung erzielt hat, dargestellt. Diese Darstellung umfasst sowohl eine ausführliche Darstellung der grundlegenden Thematik als auch die Diskussion der im Rahmen des Projekts erfolgten prototypischen Umsetzung. Daneben werden die betrieblichen Nutzenaspekte, die durch die Anwendung der beschriebenen Verfahren resultieren können, beschrieben. Nähere Informationen zu den in diesem Band dargestellten Themenstellungen sind unter www.kodok.de und www.adaptive-read.de zu finden