327 research outputs found

    Progress and perspective on polymer templating of multifunctional oxide nanostructures

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    Metal oxides are of much interest in a large number of applications, ranging from microelectronics to catalysis, for which reducing the dimensions to the nanoscale is demanded. For many of these applications, the nano-materials need to be arranged in an orderly fashion on a substrate. A typical approach is patterning thin films using lithography, but in the case of functional oxides, this is restricted to sizes down to about 100 nm due to the structural damage caused at the boundaries of the material during processing having a strong impact on the properties. In addition, for applications in which multifunctional or hybrid materials are requested, as in the case of multiferroic composites, standard top-down methods are inadequate. Here, we evaluate different approaches suitable to obtain large areas of ordered nano-sized structures and nanocomposites, with a particular focus on the literature of multiferroic nanocomposites, and we highlight the polymer-templating method as a promising low-cost alternative. (C) 2020 Author(s)

    A rapid and robust method for the cryopreservation of human granulosa cells

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    Human primary granulosa cells (GCs) derived from women undergoing oocyte retrieval can be cultured and used as a cellular model for the study of human ovarian function. In vitro, they change rapidly, initially resembling cells of the preovulatory follicle and then cells of the corpus luteum. They are derived from individual patients, whose different medical history, lifestyle and age lead to heterogeneity. Thus, cells can rarely be ideally matched for cellular experiments or, if available, only in small quantities. We reasoned that cryopreservation of human GCs may be helpful to improve this situation. Previous studies indicated the feasibility of such an approach, but low survival of human GCs was reported, and effects on human GC functionality were only partially evaluated. We tested a slow freezing protocol (employing FCS and DMSO) for human GCs upon isolation from follicular fluid. We compared cryopreserved and subsequently thawed cells with fresh, non-cryopreserved cells from the same patients. About 80% of human GCs survived freezing/thawing. No differences were found in cell morphology, survival rate in culture, or transcript~levels of mitochondrial (COX4, OPA1, TOMM20), steroidogenic (CYP11A1, CYP19A1) or cell-cell contact genes (GJA1) between the two groups in cells cultured for 1-5~days. A proteomic analysis revealed no statistically significant change in the abundance of a total of 5962 proteins. The two groups produced comparable basal levels of progesterone and responded similarly to hCG with elevation of progesterone. Taken together, our results show this to be a rapid and readily available method for the cryopreservation of human GCs. We anticipate that it will allow future large-scale experiments and may thereby improve cellular studies with human ovarian cells

    Nanoscale Networks of Metal Oxides by Polymer Imprinting and Templating for Future Adaptable Electronics

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    While network formation is prevalent in nature, networks are generally not expected in inorganic structures. Exceptions are those cases in which surface states become important, such as nanoparticles. However, even in these cases, the morphology of these networks is difficult to control and they show a large degree of disorder. In this work, we show that highly ordered and interconnected nanoscale networks of functional metal oxides can be fabricated by a combination of polymer imprinting and polymer templating through solution processable methods. We report the fabrication of a number of functional oxide networks (i.e., BiFeO3, SrTiO3, La0.7Ca0.3MnO3, and HfO2) from solution, showing that all the oxide materials tried so far are able to follow the self-assembled network morphology dictated by the polymer structure. These networks were characterized for the overall structure by scanning electron microscopy and atomic force microscopy (AFM). Grazing incidence small angle X-ray scattering showed a good imprint quality on the mm2 scale for the combined networks, which is challenging given that multiple processing steps were involved during the fabrication. The material stoichiometries were investigated by X-ray photoemission spectroscopy and the crystal phases by grazing incidence wide angle X-ray scattering. When electronic functionality is anticipated, the networks behave as expected: conducting AFM on the La0.7Ca0.3MnO3 networks confirmed the conductive character of this composition; and piezoresponse force microscopy of the BiFeO3 network is consistent with the presence of ferroelectric behavior. These nanoscale networks show promise for future applications in adaptable electronics, such as neuromorphic computing or brain-inspired information processing.</p

    Two case reports with literature review of the EEC syndrome: Clinical presentation and management

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    We report on siblings who suffer from EEC syndrome and show our experiences of the `Basel concept` of cleft lip/palate repair based on the early, one-stage closure of all components. It is performed in the age of 3-4 months to provide early normal conditions for anatomy and muscle function

    Biased small-molecule ligands for selective inhibition of HIV-1 cell entry via CCR5

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    Since the discovery of HIV's use of CCR5 as the primary coreceptor in fusion, the focus on developing small‐molecule receptor antagonists for inhibition hereof has only resulted in one single drug, Maraviroc. We therefore investigated the possibility of using small‐molecule CCR5 agonists as HIV‐1 fusion inhibitors. A virus‐free cell‐based fusion reporter assay, based on mixing “effector cells” (expressing HIV Env and luciferase activator) with “target cells” (expressing CD4, CCR5 wild type or a selection of well‐described mutations, and luciferase reporter), was used as fusion readout. Receptor expression was evaluated by ELISA and fluorescence microscopy. On CCR5 WT, Maraviroc and Aplaviroc inhibited fusion with high potencies (EC (50) values of 91 and 501 nM, respectively), whereas removal of key residues for both antagonists (Glu283Ala) or Maraviroc alone (Tyr251Ala) prevented fusion inhibition, establishing this assay as suitable for screening of HIV entry inhibitors. Both ligands inhibited HIV fusion on signaling‐deficient CCR5 mutations (Tyr244Ala and Trp248Ala). Moreover, the steric hindrance CCR5 mutation (Gly286Phe) impaired fusion, presumably by a direct hindrance of gp120 interaction. Finally, the efficacy switch mutation (Leu203Phe) – converting small‐molecule antagonists/inverse agonists to full agonists biased toward G‐protein activation – uncovered that also small‐molecule agonists can function as direct HIV‐1 cell entry inhibitors. Importantly, no agonist‐induced receptor internalization was observed for this mutation. Our studies of the pharmacodynamic requirements for HIV‐1 fusion inhibitors highlight the possibility of future development of biased ligands with selective targeting of the HIV–CCR5 interaction without interfering with the normal functionality of CCR5

    Socio-technical modelling of customer roles in developing low voltage distribution networks

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    The transition of low voltage (LV) distribution networks towards more intelligent and smart microgrids is dependent on both technical and behavioral factors, thus forming a socio-technical systems change. Sociotechnical aspects need to be taken into account when developing concepts and models to establish and manage successful niche experiments. This paper presents a new framework to model actor (customer) evolution and engagement in the process of developing smart LV Microgrid distribution networks as socio-technical systems. The framework is based on combining the Multi-level perspective (MLP) and the Strategic niche management (SNM) approach with the Unified Modeling Language (UML) tool. Customer engagement is an essential element in SNM, wherefore understanding their and other actors’ different development paths is invaluable to uncover the dynamics of the Microgrid transition in the societal and the technical contexts. The proposed framework could be applied to other key actors such as DSOs and energy retailers. The benefit of the models created by the developed framework is the articulation of expectations and visions as well as building up the networks in the SNM.fi=vertaisarvioitu|en=peerReviewed

    "Ich habe einen normalen Account, einen privaten Account und einen Fake Account." Instagram aus der Perspektive von 12- bis 15-JÀhrigen mit besonderem Fokus auf die GeschlechterprÀsentation. AusgewÀhlte Ergebnisse der Monitoring-Studie

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    Instagram zĂ€hlt zu den beliebtesten und hĂ€ufig genutzten Social-Media-Apps der 12- bis 15-JĂ€hrigen. Der vorliegende ACT ON! Short Report geht der Frage nach, wie die jugendlichen Instagram-Nutzer*innen unter dem Blickwinkel von Teilhabe- und SchutzbedĂŒrfnissen mit dieser bildorientierten Plattform umgehen. Er gibt einen Überblick ĂŒber ihr dortiges Informationsverhalten im Bezug auf identitĂ€tsrelevante Themen. Schwerpunkte bilden der Umgang der Jugendlichen mit Inhalte- und Interaktionsrisiken sowie ihre Nutzung und Bewertung von Schutzfunktionen auf Instagram, aber auch ihre Entwicklung von kreativen Lösungen zur ErfĂŒllung ihrer SchutzbedĂŒrfnisse. Ein weiterer Fokus liegt auf der Selbstdarstellung der Heranwachsenden auf Instagram und ihre diesbezĂŒgliche Orientierung an Vorbildern, wobei ihr Umgang mit Geschlechterstereotypen und geschlechtlicher DiversitĂ€t im Mittelpunkt steht. Die Themen Schönheitsideale, Geschlechterstereotype und geschlechtliche DiversitĂ€t auf Instagram diskutieren die befragten Jugendlichen kontrovers. Dies betrifft Profile von Social-Media-Stars wie Kylie Jenner oder Twenty4tim, aber auch ihre eigene Selbstdarstellung. Die Haltungen zu geschlechtlich uneindeutigen Selbstdarstellungen reichen von wohlwollender Anerkennung bis zu rigider Ablehnung. Ungesunde Modetrends sowie die Verwendung von Foto- und Videofiltern sind umstritten, eine sexualisierte Selbstdarstellung ist in der Peergroup teilweise verpönt. Aber nicht alle sehen zweifelhafte Vorbilder kritisch, vielmehr offenbaren sich hier Dilemmata und ZwĂ€nge. (Verfasser*innen
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