Azobenzene-Based Organic Salts with Ionic Liquid and Liquid Crystalline Properties

Two sets of new azobenzene-based bromide salts are synthesized, and their thermal photochromic properties are studied. Both sets are based on the imidazolium cation. The first set (1) features a symmetric biscation where two imidazolium head groups (Im) with different alkyl chains (Cn) are connected to a central azobenzene unit (Azo): [Azo(C1-Im-Cn)2]; n = 6, 8, 10, 12, 14. The other one contains an n-alkyl-imidazolium cation (Cn-Im) bearing a terminal azobenzene unit (C1-Azo) substituted with an alkoxy chain (O-Cm) of either two (2) or six (3) carbon atoms: [C1-Azo-O-Cm-Im-Cn]; m = 2, n = 8, 10, 12 and m = 6, n = 8, 10, 12, 14, 16. For both cation classes, the influence of alkyl chains of varying length on the thermal phase behavior was investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). For five compounds (Azo(-C1-Im-C12)2 (1d), Azo(-C1-Im-C12)2 (1e), C1-Azo-O-C2-Im-C10 (2b), C1-Azo-O-C2-Im-C12 (2c), and C1-Azo-O-C6-Im-C16 (3e)), the formation of a liquid crystalline phase was observed. The biscationic salts (1) are all comparatively high melting organic salts (180–240 °C), and only the two representatives with long alkylchains (C12 and C14) exhibit liquid crystallinity. The monocationic salts with an O–C2 bridge (2) melt between 140 and 170 °C depending on the alkyl chain length, but from an alkyl chain of 10 and more carbon atoms on they form a smectic A liquid crystalline phase. The representatives of the third set with a O–C6 bridge qualify as ionic liquids with melting points less than 100 °C. However, only the representative with a hexadecyl chain forms a liquid crystalline phase. Representative single crystals for all sets of cations could be grown that allowed for single crystal structure analysis. Together with small-angle X-ray scattering experiments they allow for a more detailed understanding of the thermal properties. Through irradiation with UV-light (320–366 nm) all compounds undergo trans–cis isomerization, which reverses under visible light (440 nm).Reprinted (adapted) with permission from Cryst. Growth Des., 2015, 15 (9), pp 4701–4712. Copyright 2015 American Chemical Society.</p

CD44 Upregulation in E-Cadherin-Negative Esophageal Cancers Results in Cell Invasion

E-cadherin is frequently lost during epithelial-mesenchymal transition and the progression of epithelial tumorigenesis. We found a marker of epithelial-mesenchymal transition, CD44, upregulated in response to functional loss of E-cadherin in esophageal cell lines and cancer. Loss of E-cadherin expression correlates with increased expression of CD44 standard isoform. Using an organotypic reconstruct model, we show increased CD44 expression in areas of cell invasion is associated with MMP-9 at the leading edge. Moreover, Activin A increases cell invasion through CD44 upregulation after E-cadherin loss. Taken together, our results provide functional evidence of CD44 upregulation in esophageal cancer invasion

Whose legitimacy beliefs count? Targeted audiences in global governance legitimation processes

Which groups do global governance institutions address in their efforts to legitimate themselves? Global governance institutions are increasingly attempting to present themselves as legitimate vis-à-vis both internal and external audiences. Yet, empirical research on these legitimation audiences is still nascent. This article proposes a conceptual framework that highlights the selection of audiences by global governance institutions as a key element of their self-legitimation. Specifically, we argue that our approach addresses three continuing challenges in empirical research on self-legitimation. First, it emphasises how different actors within the institution may pursue multiple, and potentially conflicting, strategies with regard to the legitimation audiences they address. Second, our framework calls attention to what we call intermediary legitimation audiences, that is, audiences targeted with the expectation that they will in turn convince other audiences of the institution’s legitimacy. Finally, instead of taking for granted that external critique steers who is targeted by self-legitimation, our approach highlights that an institution’s internal assessment of such critique is decisive. We demonstrate the wide applicability of our framework through exploratory studies of three global governance institutions that differ with regard to their membership compositions: the World Health Organization, the International Criminal Court and the Forest Stewardship Council

Traitement aux déversoirs d'orage : rendements sur les paramètres responsables de la déperdition d'oxygène via la rétention et l’infiltration dans le sol

Colloque avec actes et comité de lecture. Internationale.International audienc