Suchergebnisse

This manuscript is being submitted to an open source publication. In this repository you will find the minauscript, supplementary information as well as data use to prepare this manuscript. ; We employed Environmental Scanning Electron Microscopy (ESEM) in water vapor to study the complete scenario of ice growth, coalescence of crystallites, polycrystalline film morphology and sublimation, in the temperature range of 10ºC to 20ºC. First, individual ice crystals grow in the shape of micron-sized hexagonal columns with stable basal faces. Their coalescence during further growth forms thick polycrystalline films, consisting of large grains separated by grain boundaries. The latter are composed of 1 3 µm wide pores, which are attributed to the coalescence of defective crystallite surfaces. Sublimation of isolated crystals and of films is defect-driven, and grain boundaries play a decisive role. A scallop-like concave structure forms, limited by sharp ridges, which are terminated with nanoscale tips. ; We are indebted to C. Tollan, CIC nanogune, for technical help with the ESEM. We are grateful to Prof. H. Mader, Bristol University for discussions on ice veins. We thank Prof. A. Chuvilin, CIC nanoGUNE, for discussing beam damage and contrast mechanisms. We acknowledge funding from FEI (Eindhoven, NL), Elkartek 2015 and 2019 (Basque Government), the Spanish MINECO grants PID2019 104650GB and MAT2013 46006 R, Basque Government Grant Proyecto de Investigación PI2013 57, and from the Maria de Maeztu "Units of Excellence" Programme MDM 2016 0618 (MINECO). S.M. acknowledges York University and CIC nanoGUNE for their support during her sabbatical and subsequent visits.

Wie gelingt eine tragfähige Umweltbildung in Zeiten sich wandelnder Sozialstrukturen und angesichts eines geänderten Mediennutzungsverhaltens von Jugendlichen? Diese Frage diskutierten Fachleute aus dem Schulwesen, aus Umweltbildungszentren, Universitäten, Museen, Großschutzgebieten sowie Experten neuer Medien im Rahmen eines Fachsymposiums. Betont wurde dabei die Bedeutung eines kontinuierlichen Dialogs der Umweltbildungsakteure, ebenso wie die stete Qualitätssicherung und Qualitätsentwicklung für alle Bereiche der Umweltbildung. Dieser Band fasst die Vorträge der 14. Sommerakademie der Deutschen Bundesstiftung Umwelt (DBU) zusammen. Er wendet sich gleichermaßen an Pädagogen in schulischen, außerschulischen und berufsbildenden Einrichtungen, an Umweltbildungsakteure, Vertreter aus Wissenschaft, Politik und Gesellschaft sowie an interessierte Laien, die sich Rat von fachlicher Seite erhoffen.Wie gelingt eine tragfähige Umweltbildung in Zeiten sich wandelnder Sozialstrukturen und angesichts eines geänderten Mediennutzungsverhaltens der Jugendlichen?

The epidemic spread of many viral infections is mediated by the environmental conditions and influenced by the ambient humidity. Single virus particles have been mainly visualized by atomic force microscopy (AFM) in liquid conditions, where the effect of the relative humidity on virus topography and surface cannot be systematically assessed. In this work, we employed multi-frequency AFM, simultaneously with standard topography imaging, to study the nanoscale wetting of individual Tobacco Mosaic virions (TMV) from ambient relative humidity to water condensation (RH > 100%). We recorded amplitude and phase vs. distance curves (APD curves) on top of single virions at various RH and converted them into force vs. distance curves. The high sensitivity of multifrequency AFM to visualize condensed water and sub-micrometer droplets, filling gaps between individual TMV particles at RH > 100%, is demonstrated. Dynamic force spectroscopy allows detecting a thin water layer of thickness ⁓1 nm, adsorbed on the outer surface of single TMV particles at RH < 60%. ; We acknowledge the support of the Diputación Foral de Guipuzcoa under the project Nanoscopía Mojada (PCTi 2015), of the Basque government (PI2013-57, Elkartek ng20), and from grants MAT2013-4006-R, PID2019-104650GB-C22 and Maria de Maeztu "Units of Excellence" program MDM-2016-0618 (all MCIU-MINECO, Spain). TMV solutions were provided by the group of Prof. Christina Wege (Institute for Biomaterials and Biomolecular Systems, University of Stuttgart). A.C. acknowledges Javier Zaldivar (CIC nanoGUNE, Tolosa Hiribidea 76, E-20018 Donostia-San Sebastian) for useful discussions.

Biological material has gained increasing attention recently as a source of ice-nucleating particles that may account for cloud glaciation at moderate supercooling. While the ice-nucleation (IN) ability of some bacteria can be related to membrane-bound proteins with epitaxial fit to ice, little is known about the IN-active entities present in biological material in general. To elucidate the potential of proteins and viruses to contribute to the IN activity of biological material, we performed bulk freezing experiments with the newly developed drop freezing assay DRoplet Ice Nuclei Counter Zurich (DRINCZ), which allows the simultaneous cooling of 96 sample aliquots in a chilled ethanol bath. We performed a screening of common proteins, namely the iron storage protein ferritin and its iron-free counterpart apoferritin, the milk protein casein, the egg protein ovalbumin, two hydrophobins, and a yeast ice-binding protein, all of which revealed IN activity with active site densities > 0.1 mg−1 at −10 ∘C. The tobacco mosaic virus, a plant virus based on helically assembled proteins, also proved to be IN active with active site densities increasing from 100 mg−1 at −14 ∘C to 10 000 mg−1 at −20 ∘C. Among the screened proteins, the IN activity of horse spleen ferritin and apoferritin, which form cages of 24 co-assembled protein subunits, proved to be outstanding with active site densities > 10 mg−1 at −5 ∘C. Investigation of the pH dependence and heat resistance of the apoferritin sample confirmed the proteinaceous nature of its IN-active entities but excluded the correctly folded cage monomer as the IN-active species. A dilution series of apoferritin in water revealed two distinct freezing ranges, an upper one from −4 to −11 ∘C and a lower one from −11 to −21 ∘C. Dynamic light scattering measurements related the upper freezing range to ice-nucleating sites residing on aggregates and the lower freezing range to sites located on misfolded cage monomers or oligomers. The sites proved to persist during several freeze–thaw cycles performed with the same sample aliquots. Based on these results, IN activity seems to be a common feature of diverse proteins, irrespective of their function, but arising only rarely, most probably through defective folding or aggregation to structures that are IN active. ; This research has been supported by the Swiss National Foundation (grant nos. IZSEZ0_179149/1 and 200021_156581), the Basque government (Elkartek programmes ng 15 and ng 17), and the Spanish MINECO (grant no. MAT2013- 46006-R, programme MDM-2016-0618).

Die AutorInnen untersuchen, inwiefern Bildung für nachhaltige Entwicklung (BNE) bei außerschulischen Bildungsanbietern Fuß gefasst hat. Die Befunde zeigen, das BNE in Veranstaltungen und Leitbildern außerschulischer Anbieter angekommen ist. Doch die Potenziale können noch besser genutzt werden, wenn BNE-Kompetenzen gestärkt, Kooperationspartner besser vernetzt und Entscheidungsträger aus Wirtschaft und Politik vermehrt eingebunden werden.

Der Sammelband behandelt das Thema in bemerkenswerter Breite: Einführend gibt Konrad Ott (vgl. "Handbuch Umweltethik", ID-G 7/17, und "Umweltethik zur Einführung", ID-G 33/10) eine Einordnung der Umweltethik als "Teildisziplin der praktischen Philosophie" und umreisst problemorientiert ihr Aufgabenspektrum. Auch die folgenden Beiträge begründen und vertiefen Ziele, kommunikative Aspekte, gesellschaftliche Interessenlagen und entwerfen schliesslich bildungspolitische Ziele. Der 2. Teil des Buchs beschäftigt sich mit der Vermittlung umweltethischer Fragestellungen an Kinder (Vor- und Grundschulalter), wobei der ganzheitliche Ansatz, naturwissenschaftliche und "philosophische" Fragestellungen miteinander zu verbinden, von methodischer Relevanz ist. Dazu gibt es im praktischen Teil des Bandes viele Vorschläge und Anregungen zur praktischen Arbeit. - Zielgruppe sind Umweltbildner/-innen, Erzieher/-innen, Grundschullehrer/-innen. (2)