"Multi-culti“ vs. ”another cell phone store“ – Changing ethnic, social, and commercial diversities in Berlin-Neukölln.

Based on an extensive ethnography of the economic and social life in Berlin-Neukölln, the paper asks how a changing demographic and social structure affects the social life but also the urban renewal on two iconic but contested streets - “the Arab street” Sonnenallee and adjacent Karl-Marx-Straße. The effects of migration - and particularly of the more recent refugee migration - to Berlin are explored through the reshaping and diversification processes of the physical and social spaces of the two streets and their businesses. In detail, the paper illuminates the changing ordinary everyday interactions and social and spatial practices in and around local shops and gastronomic facilities and argues that it is the interactions in and around certain shops and businesses that contribute to the everyday practice of urban diversity. The paper further reveals that regardless of the place-and community-making of the local store owners and staff therein, the local urban renewal and regeneration actors have a very different understanding of these spaces and their operators and also aim for a different kind of new “diversity”. The paper thus concludes by also showing how these actors frame and depict the increasingly ethnically diverse businesses on the two streets in the course of urban renewal, including a critical discussion of their perceptions and concrete practices as in contrast to the ethnically diverse business peoples’ perceptions and placemaking practices that often also represent homemaking practices

Functional inhibition of acid sphingomyelinase by Fluphenazine triggers hypoxia-specific tumor cell death

Owing to lagging or insufficient neo-angiogenesis, hypoxia is a feature of most solid tumors. Hypoxic tumor regions contribute to resistance against antiproliferative chemotherapeutics, radiotherapy and immunotherapy. Targeting cells in hypoxic tumor areas is therefore an important strategy for cancer treatment. Most approaches for targeting hypoxic cells focus on the inhibition of hypoxia adaption pathways but only a limited number of compounds with the potential to specifically target hypoxic tumor regions have been identified. By using tumor spheroids in hypoxic conditions as screening system, we identified a set of compounds, including the phenothiazine antipsychotic Fluphenazine, as hits with novel mode of action. Fluphenazine functionally inhibits acid sphingomyelinase and causes cellular sphingomyelin accumulation, which induces cancer cell death specifically in hypoxic tumor spheroids. Moreover, we found that functional inhibition of acid sphingomyelinase leads to overactivation of hypoxia stress-response pathways and that hypoxia-specific cell death is mediated by the stress-responsive transcription factor ATF4. Taken together, the here presented data suggest a novel, yet unexplored mechanism in which induction of sphingolipid stress leads to the overactivation of hypoxia stress-response pathways and thereby promotes their pro-apoptotic tumor-suppressor functions to specifically kill cells in hypoxic tumor areas

The Places Where Community Is Practiced

In this open access publication, the social cohesion of urban neighborhoods and their residents is examined, which is often viewed as vulnerable since increased mobility, individualization, wider socio-economic and demographic changes have fundamentally altered the basis for everyday social interaction in urban neighborhoods. Anna Steigemann gives scholarly attention to the concrete places where neighborly interactions still take place and to how these interactions affect local community building. She illuminates and explores the ordinary everyday interactions and social practices in and around shops and gastronomic facilities on a shopping street in Berlin-Neukölln, revealing how these businesses are important places where community is practiced, but also why they are increasingly threatened by commercial and residential gentrification

The Places Where Community Is Practiced

In this open access publication, the social cohesion of urban neighborhoods and their residents is examined, which is often viewed as vulnerable since increased mobility, individualization, wider socio-economic and demographic changes have fundamentally altered the basis for everyday social interaction in urban neighborhoods. Anna Steigemann gives scholarly attention to the concrete places where neighborly interactions still take place and to how these interactions affect local community building. She illuminates and explores the ordinary everyday interactions and social practices in and around shops and gastronomic facilities on a shopping street in Berlin-Neukölln, revealing how these businesses are important places where community is practiced, but also why they are increasingly threatened by commercial and residential gentrification

Ligand binding cavity encoded as a local hydrophobicity deficiency

The above diagram illustrates the specific deviation from the theoretical distribution of hydrophobicity which is associated with the presence of a ligand binding cavity

On the change of energy caused by crack propagation in 3-dimensional anisotropic solids

summary:Crack propagation in anisotropic materials is a persistent problem. A general concept to predict crack growth is the energy principle: A crack can only grow, if energy is released. We study the change of potential energy caused by a propagating crack in a fully three-dimensional solid consisting of an anisotropic material. Based on methods of asymptotic analysis (method of matched asymptotic expansions) we give a formula for the decrease in potential energy if a smooth inner crack grows along a small crack extension

Syndecan, a heparan sulphate proteoglycan, is involved in myotube and axonal guidance in Drosophila melanogaster

Slit ist ein extrazelluläres Signalmolekül, welches von Glia-Zellen der ventralen Mittellinie sezerniert als ein abstoßendes Signal wirkt, das Axone an einer Überquerung der Mittellinie hindert. Zusätzlich wirkt Slit als ein regulierender Faktor bei Migrationsprozessen von Muskelvorläuferzellen und ventralen Zweigen des Tracheensystems. Slit bindet an Rezeptoren der Robo-Familie. Syndecan ist ein Transmembranprotein, in dessen extrazellulärem Bereich Heparansulfat-Glykosaminoglykan-Ketten (HSGAG) kovalent gebunden sind. Heparansulfat-Proteoglykane spielen eine Rolle in der Regulation extrazellulärer Signalwege. In der vorliegenden Arbeit wurde die Funktion von Sdc während gerichteter Migrationsprozesse in den Muskeln, im Nerven- und im Tracheensystem näher charakterisiert. sdc-Mutanten zeigen ähnliche Phänotypen, wie Mutanten in Genen des Slit/Robo-Signalwegs und Sdc kolokalisiert mit dem Robo-Rezeptor auf den longitudinalen Axonen des ZNS und an den Apodemen. Genetische Interaktionsstudien konnten Sdc als Teil des Slit/Robo-Signalwegs identifizieren: sdc-Allele zeigen genetische Interaktionen mit slit- sowie mit robo- und robo2-Allelen. In gewebespezifischen Normalisierungsexperimenten konnte ferner gezeigt werden, dass Sdc ausschließlich an den Slit-Rezipientenzellen notwendig ist. Eine eigenständige Rezeptorfunktion von Sdc mit einer Signalfunktion auf cytoplasmatische Faktoren über die konservierte cytoplasmatische Region konnte ausgeschlossen werden, da eine carboxyterminal deletierte Form von Sdc volle Sdc-Aktivität im Slit/Robo-Signalweg bereitstellt. Diese Ergebnisse zeigen, daß Syndecan ein Teil des Slit/Robo-Sigalwegs ist. Die Funktion von Syndecan auf den Slit-Rezipientenzellen besteht wahrscheinlich in der Präsentation membrangebundener HSGAG-Ketten, die die Interaktion des Slit-Liganden mit dem Robo-Rezeptor erleichtern.Slit, the ligand for the Roundabout (Robo) receptors is secreted from midline cells of the Drosophila central nervous system (CNS). It acts as a short-range repellent that controls midline crossing of axons and allows growth cones to select specific pathways along each side of the midline. In addition, Slit directs the migration of muscle precursors and of ventral branches of the tracheal system, showing that it provides long-range activity beyond the limit of the developing CNS . Biochemical studies on the mammalian homologues of Slit and Robo suggested that guidance activity requires cell-surface heparan sulphate to promote Slit/Robo-binding. The invertebrate homolog of Syndecan in the fly was identified in a screen for novel factors that are involved in myotube guidance. In this work I show that this heparan sulphate proteoglycan is required for proper Slit-signalling. Syndecan colocalizes with the Robo-Receptor at the longitudinal axon tracts and at the muscle attachment sites. Mutations of the Drosophila gene syndecan affect all aspects of Slit activity and cause robo-like phenotypes. sdc genetically interacts with robo and slit, and double mutations cause a synergistic strengthening of the single mutant phenotypes. Additionally, tissue specific rescue experiments show that Syndecan is required at the Slit-receiving cells. Rescue experiments with C-terminal truncated versions of Syndecan show that the highly conserved cytoplasmic domain of Syndecan is not important but an attachment of Syndecan to the cell membrane is important for the function of Syndecan in Slit/Robo-signaling. The results suggest that Syndecan is a necessary component of Slit/Robo-signaling. Syndecan is needed at the Slit-receiving cells and most likely acts to present membrane-bound heparan sulphate glycosaminoglycan sugar-chains to facilitate Slit/Robo-signaling

The Places Where Community Is Practiced : How Store Owners and Their Businesses Build Neighborhood Social Life

In this open access publication, the social cohesion of urban neighborhoods and their residents is examined, which is often viewed as vulnerable since increased mobility, individualization, wider socio-economic and demographic changes have fundamentally altered the basis for everyday social interaction in urban neighborhoods. Anna Steigemann gives scholarly attention to the concrete places where neighborly interactions still take place and to how these interactions affect local community building. She illuminates and explores the ordinary everyday interactions and social practices in and around shops and gastronomic facilities on a shopping street in Berlin-Neukölln, revealing how these businesses are important places where community is practiced, but also why they are increasingly threatened by commercial and residential gentrification.TU Berlin, Open-Access-Mittel - 201

Recent developments in LIBXC — A comprehensive library of functionals for density functional theory

LIBXC is a library of exchange–correlation functionals for density-functional theory. We are concerned with semi-local functionals (or the semi-local part of hybrid functionals), namely local-density approximations, generalized-gradient approximations, and meta-generalized-gradient approximations. Currently we include around 400 functionals for the exchange, correlation, and the kinetic energy, spanning more than 50 years of research. Moreover, LIBXC is by now used by more than 20 codes, not only from the atomic, molecular, and solid-state physics, but also from the quantum chemistry communities. © 2017 The AuthorsPeer reviewe

Panels of chemically-modified heparin polysaccharides and natural heparan sulfate saccharides exhibit differences in binding to Slit and Robo, as well as variation between protein binding and cellular activity.

Heparin/ heparan sulfate (HS) glycosaminoglycans are required for Slit-Robo cellular responses. Evidence exists for interactions between each combination of Slit, Robo and heparin/HS and for formation of a ternary complex. Heparin/HS are complex mixtures displaying extensive structural diversity. The relevance of this diversity has been studied to a limited extent using a few select chemically-modified heparins as models of HS diversity. Here we extend these studies by parallel screening of structurally diverse panels of eight chemically-modified heparin polysaccharides and numerous natural HS oligosaccharide chromatographic fractions for binding to both Drosophila Slit and Robo N-terminal domains and for activation of a chick retina axon response to the Slit fragment. Both the polysaccharides and oligosaccharide fractions displayed variability in binding and cellular activity that could not be attributed solely to increasing sulfation, extending evidence for the importance of structural diversity to natural HS as well as model modified heparins. They also displayed differences in their interactions with Slit compared to Robo, with Robo preferring compounds with higher sulfation. Furthermore, the patterns of cellular activity across compounds were different to those for binding to each protein, suggesting that biological outcomes are selectively determined in a subtle manner that does not simply reflect the sum of the separate interactions of heparin/HS with Slit and Robo