Cell-autonomous and environmental contributions to the interstitial migration of T cells

A key to understanding the functioning of the immune system is to define the mechanisms that facilitate directed lymphocyte migration to and within tissues. The recent development of improved imaging technologies, most prominently multi-photon microscopy, has enabled the dynamic visualization of immune cells in real-time directly within intact tissues. Intravital imaging approaches have revealed high spontaneous migratory activity of T cells in secondary lymphoid organs and inflamed tissues. Experimental evidence points towards both environmental and cell-intrinsic cues involved in the regulation of lymphocyte motility in the interstitial space. Based on these data, several conceptually distinct models have been proposed in order to explain the coordination of lymphocyte migration both at the single cell and population level. These range from “stochastic” models, where chance is the major driving force, to “deterministic” models, where the architecture of the microenvironment dictates the migratory trajectory of cells. In this review, we focus on recent advances in understanding naïve and effector T cell migration in vivo. In addition, we discuss some of the contradictory experimental findings in the context of theoretical models of migrating leukocytes

Inventarisierung und Potentialanalyse von Dachbegrünung

In Kooperation mit dem Deutschen Dachgärtner Verband hat das DLR eine Methode entwickelt, um mit Hilfe von Luftbildaufnahmen und Gebäudebasisdaten bereits existierende Gründächer automatisiert zu erfassen und deren Zustand zu bewerten. Ein zweiter Aspekt betrifft die Identifizierung potentiell begrünbarer Dachflächen

Green Roof Inventory and Potential Analysis

The new remote sensing technology for the identification of already existing Green Roofs and potential Green Roof sites provides municipalities with the opportunity to use this data for sustainable urban planning decisions in the field of urban climate modelling, drainage system calculation and biodiversity networks. Furthermore, this technology is carried out automatically - which is a great asset with respect to current approaches based on photointerpretation or even in situ surveys by experts – once provided with new suitable imagery, it allows easy and straightforward updates

Kommunale Gründach-Strategien Inventarisierung, Potentialanalyse, Praxisbeispiele

Vor dem Hintergrund der aktuellen Klimaentwicklung stehen begrünte Dächer weiter im Fokus der Aufmerksamkeit. Egal, ob es sich dabei um Regenwasserrückhalt, sommerliche Hitzeabwehr oder den Schutz der Dachabdichtung vor Temperaturextremen und Hagelschäden handelt – mit ihren vielfältigen Vorteilen liefert die Umwelttechnik Dachbegrünung ein perfektes Werkzeug, um diese Herausforderungen zu meistern. Viele Städte räumen begrünten Dächern deshalb im Rahmen ihrer Anpassungspläne an den Klimawandel eine besonders hohe Priorität ein. Auf nationaler Ebene findet dieser Ansatz Unterstützung durch das Grünbuch „Stadtgrün“ des Bundesministeriums für Umwelt, Naturschutz, Bau und Reaktorsicherheit (BMUB) und die branchenübergreifende Charta „Zukunft Stadt und Grün“, die vom Bundesverband Garten-, Landschafts- und Sportplatzbau e. V. (BGL) und der Stiftung DIE GRÜNE STADT ins Leben gerufen wurde. Mit der vorliegenden Broschüre „Kommunale Gründach-Strategien – Inventarisierung, Potenzialanalyse, Praxisbeispiele“ möchten wir Ihnen zeigen, wie vielfältig die Einsatz- und Fördermöglichkeiten begrünter Dächer auf kommunaler Ebene sein können. Neben aktuellen Gründach-Initiativen aus Berlin, Hamburg, Hannover, Ludwigsburg und Stuttgart stellen wir Ihnen dabei auch das spannende Forschungsprojekt „Inventarisierung und Potenzialanalyse von Dachbegrünung“ vor. Unter der Projektleitung des Deutschen Dachgärtner Verbandes hat das Deutsche Zentrum für Luft- und Raumfahrt (DLR) ein fernerkundliches Verfahren entwickelt, das auf Grundlage von Luftbildaufnahmen und Gebäudebasisdaten bereits vorhandene Dachbegrünungen identifizieren kann und mögliche Potenzialflächen in der Dachlandschaft ausweist. Jedes Jahr werden in Deutschland mehrere Millionen Quadratmeter Dachbegrünung neu installiert. Gleichzeitig wird aber nach wie vor der größte Teil der Dachflächen ohne Begrünung ausgeführt und leistet dadurch keinen Beitrag zur Verbesserung der Umweltund Lebensqualität in den Städten. Eine Flächenverschwendung, die wir uns in Zeiten des Klimawandels und der zunehmenden Urbanisierung nicht leisten können

Ozone pollution and ozone biomonitoring in European cities. Part I: Ozone concentrations and cumulative exposure indices at urban and suburban sites

International audienceIn the frame of a European research project on air quality in urban agglomerations, data on ozone concentrations from 23 automated urban and suburban monitoring stations in 11 cities from seven countries were analysed and evaluated. Daily and summer mean and maximum concentrations were computed based on hourly mean values, and cumulative ozone exposure indices (Accumulated exposure Over a Threshold of 40 ppb (AOT40), AOT20) were calculated. The diurnal profiles showed a characteristic pattern in most city centres, with minimum values in the early morning hours, a strong rise during the morning, peak concentrations in the afternoon, and a decline during the night. The widest amplitudes between minimum and maximum values were found in central and southern European cities such as Du¨ sseldorf, Verona, Klagenfurt, Lyon or Barcelona. In the northern European cities of Edinburgh and Copenhagen, by contrast, maximum values were lower and diurnal variation was much smaller. Based on ozone concentrations as well as on cumulative exposure indices, a clear north–south gradient in ozone pollution, with increasing levels from northern and northwestern sites to central and southern European sites, was observed. Only the Spanish cities did not fit this pattern; there, ozone levels were again lower than in central European cities, probably due to the direct influence of strong car traffic emissions. In general, ozone concentrations and cumulative exposure were significantly higher at suburban sites than at urban and traffic-exposed sites. When applying the newly established European Union (EU) Directive on ozone pollution in ambient air, it was demonstrated that the target value for the protection of human health was regularly surpassed at urban as well as suburban sites, particularly in cities in Austria, France, northern Italy and southern Germany. European target values and long-term objectives for the protection of vegetation expressed as AOT40 were also exceeded at many monitoring sites

Airborne trace element pollution in 11 European cities assessed by exposure of standardised ryegrass cultures

11 páginas, 2 tablas, 3 figuras.Within a European biomonitoring programme, Italian ryegrass (Lolium multiflorum Lam.) was employed as accumulative bioindicator of airbornetraceelements (As, Cd, Cr, Cu, Fe, Ni, Pb, Sb, V, Zn) in urban agglomerations. Applying a highly standardised method, grass cultures were exposed for consecutive periods of four weeks each to ambient air at up to 100 sites in 11cities during 2000–2002. Results of the 2001 exposure experiments revealed a clear differentiation of traceelementpollution within and among local monitoring networks. Pollution was influenced particularly by traffic emissions. Especially Sb, Pb, Cr, Fe, and Cu exhibited a very uneven distribution within the municipal areas with strong accumulation in plants from traffic-exposed sites in the city centres and close to major roads, and moderate to low levels in plants exposed at suburban or rural sites. Accumulation of Ni and V was influenced by other emission sources. The biomonitoring sites located in Spanish city centres featured a much higher pollution load by traceelements than those in other cities of the network, confirming previously reported findings obtained by chemical analyses of dust deposition and aerosols. At some heavily-trafficked sites, legal thresholds for Cu, Pb, and V contents in foodstuff and animal feed were reached or even surpassed. The study confirmed that the standardised grass exposure is a useful and reliable tool to monitor and to assess environmental levels of potentially toxic compounds of particulate matter.This study was supported by the LIFE Environment Programme of the European Commission under the grant LIFE/99/ENV/D/000453.CEAM is partly supported by Generalitat Valenciana, Bancaja, and CONSOLIDER-INGENIO 2010 (GRACCIE).Peer reviewe