161 research outputs found

    Das Gold in den Köpfen der Mitarbeiter : zur Integration von Ideen- und Wissensmanagement

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    Microfibers as Physiologically Relevant Platforms for Creation of 3D Cell Cultures

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    Microfibers have received much attention due to their promise for creating flexible and highly relevant tissue models for use in biomedical applications such as 3D cell culture, tissue modeling, and clinical treatments. A generated tissue or implanted material should mimic the natural microenvironment in terms of structural and mechanical properties as well as cell adhesion, differentiation, and growth rate. Therefore, the mechanical and biological properties of the fibers are of importance. This paper briefly introduces common fiber fabrication approaches, provides examples of polymers used in biomedical applications, and then reviews the methods applied to modify the mechanical and biological properties of fibers fabricated using different approaches for creating a highly controlled microenvironment for cell culturing. It is shown that microfibers are a highly tunable and versatile tool with great promise for creating 3D cell cultures with specific properties

    Mucosal melanomas of different anatomic sites share a common global DNA methylation profile with cutaneous melanoma but show location-dependent patterns of genetic and epigenetic alterations

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    Cutaneous, ocular, and mucosal melanomas are histologically indistinguishable tumors that are driven by a different spectrum of genetic alterations. With current methods, identification of the site of origin of a melanoma metastasis is challenging. DNA methylation profiling has shown promise for the identification of the site of tumor origin in various settings. Here we explore the DNA methylation landscape of melanomas from different sites and analyze if different melanoma origins can be distinguished by their epigenetic profile. We performed DNA methylation analysis, next generation DNA panel sequencing, and copy number analysis of 82 non-cutaneous and 25 cutaneous melanoma samples. We further analyzed eight normal melanocyte cell culture preparations. DNA methylation analysis separated uveal melanomas from melanomas of other primary sites. Mucosal, conjunctival, and cutaneous melanomas shared a common global DNA methylation profile. Still, we observed location-dependent DNA methylation differences in cancer-related genes, such as low frequencies of RARB (7/63) and CDKN2A promoter methylation (6/63) in mucosal melanomas, or a high frequency of APC promoter methylation in conjunctival melanomas (6/9). Furthermore, all investigated melanomas of the paranasal sinus showed loss of PTEN expression (9/9), mainly caused by promoter methylation. This was less frequently seen in melanomas of other sites (24/98). Copy number analysis revealed recurrent amplifications in mucosal melanomas, including chromosomes 4q, 5p, 11q and 12q. Most melanomas of the oral cavity showed gains of chromosome 5p with TERT amplification (8/10), while 11q amplifications were enriched in melanomas of the nasal cavity (7/16). In summary, mucosal, conjunctival, and cutaneous melanomas show a surprisingly similar global DNA methylation profile and identification of the site of origin by DNA methylation testing is likely not feasible. Still, our study demonstrates tumor location-dependent differences of promoter methylation frequencies in specific cancer-related genes together with tumor site-specific enrichment for specific chromosomal changes and genetic mutations. (c) 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland

    Volume phase transition kinetics of smart N-n-propylacrylamide microgels studied by time-resolved pressure jump small angle neutron scattering

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    Wrede O, Reimann Y, LĂŒlsdorf S, et al. Volume phase transition kinetics of smart N-n-propylacrylamide microgels studied by time-resolved pressure jump small angle neutron scattering. Scientific Reports. 2018;8(1): 13781.The use of smart colloidal microgels for advanced applications critically depends on their response kinetics. We use pressure jump small angle neutron scattering with supreme time resolution to study the rapid volume phase transition kinetics of such microgels. Utilizing the pressure induced microphase separation inside the microgels we were able to resolve their collapse and swelling kinetics. While the collapse occurs on a time scale of 10 ms, the particle swelling turned out to be much faster. Photon correlation spectroscopy and static small angle neutron scattering unambiguously show, that the much slower collapse can be associated with the complex particle architecture exhibiting a loosely-crosslinked outer region and a denser inner core region. These insights into the kinetics of stimuli-responsive materials are of high relevance for their applications as nano-actuators, sensors or drug carriers. Moreover, the used refined pressure jump small angle neutron scattering technique is of broad interest for soft matter studies

    Catching Element Formation In The Act

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    Gamma-ray astronomy explores the most energetic photons in nature to address some of the most pressing puzzles in contemporary astrophysics. It encompasses a wide range of objects and phenomena: stars, supernovae, novae, neutron stars, stellar-mass black holes, nucleosynthesis, the interstellar medium, cosmic rays and relativistic-particle acceleration, and the evolution of galaxies. MeV gamma-rays provide a unique probe of nuclear processes in astronomy, directly measuring radioactive decay, nuclear de-excitation, and positron annihilation. The substantial information carried by gamma-ray photons allows us to see deeper into these objects, the bulk of the power is often emitted at gamma-ray energies, and radioactivity provides a natural physical clock that adds unique information. New science will be driven by time-domain population studies at gamma-ray energies. This science is enabled by next-generation gamma-ray instruments with one to two orders of magnitude better sensitivity, larger sky coverage, and faster cadence than all previous gamma-ray instruments. This transformative capability permits: (a) the accurate identification of the gamma-ray emitting objects and correlations with observations taken at other wavelengths and with other messengers; (b) construction of new gamma-ray maps of the Milky Way and other nearby galaxies where extended regions are distinguished from point sources; and (c) considerable serendipitous science of scarce events -- nearby neutron star mergers, for example. Advances in technology push the performance of new gamma-ray instruments to address a wide set of astrophysical questions.Comment: 14 pages including 3 figure

    Deutschland auf dem Weg zur KlimaneutralitÀt 2045 - Szenarien und Pfade im Modellvergleich (Zusammenfassung)

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    Erstmals stellt die vorliegende Szenarienanalyse fĂŒr Deutschland konkreteTransformationspfade zur KlimaneutralitĂ€t 2045 auf der Basis eines umfassenden Modellvergleichs vor. Das Besondere an dieser Studie des Ariadne-Projektes ist, dass sechs Gesamtsystem- und Sek-tormodelle in einer Studie integriert wurden, die sich in ihren jeweiligen StĂ€rken ergĂ€nzen: FĂŒr spezifische Fragestellungen wurde jeweils dasjenige Modell als Leitmodell hervorgehoben, welches die entsprechenden Aspekte am genauesten abbildet. Weitere Modelle wurden genutzt, um Auswirkungen der Transformation auf UmweltschutzgĂŒter und die Verteilung der Kosten auf verschiedene Einkommensgruppen zu analysieren.Dieser breit gefĂ€cherte Ansatz ermöglicht es, die Implikationen der Energiewende robust und im Detail zu beschreiben

    Myelin insulation as a risk factor for axonal degeneration in autoimmune demyelinating disease

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    Axonal degeneration determines the clinical outcome of multiple sclerosis and is thought to result from exposure of denuded axons to immune-mediated damage. Therefore, myelin is widely considered to be a protective structure for axons in multiple sclerosis. Myelinated axons also depend on oligodendrocytes, which provide metabolic and structural support to the axonal compartment. Given that axonal pathology in multiple sclerosis is already visible at early disease stages, before overt demyelination, we reasoned that autoimmune inflammation may disrupt oligodendroglial support mechanisms and hence primarily affect axons insulated by myelin. Here, we studied axonal pathology as a function of myelination in human multiple sclerosis and mouse models of autoimmune encephalomyelitis with genetically altered myelination. We demonstrate that myelin ensheathment itself becomes detrimental for axonal survival and increases the risk of axons degenerating in an autoimmune environment. This challenges the view of myelin as a solely protective structure and suggests that axonal dependence on oligodendroglial support can become fatal when myelin is under inflammatory attack

    Simulation and sensitivities for a phased IceCube-Gen2 deployment

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    Mechanical design of the optical modules intended for IceCube-Gen2

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    IceCube-Gen2 is an expansion of the IceCube neutrino observatory at the South Pole that aims to increase the sensitivity to high-energy neutrinos by an order of magnitude. To this end, about 10,000 new optical modules will be installed, instrumenting a fiducial volume of about 8 km3. Two newly developed optical module types increase IceCube’s current sensitivity per module by a factor of three by integrating 16 and 18 newly developed four-inch PMTs in specially designed 12.5-inch diameter pressure vessels. Both designs use conical silicone gel pads to optically couple the PMTs to the pressure vessel to increase photon collection efficiency. The outside portion of gel pads are pre-cast onto each PMT prior to integration, while the interiors are filled and cast after the PMT assemblies are installed in the pressure vessel via a pushing mechanism. This paper presents both the mechanical design, as well as the performance of prototype modules at high pressure (70 MPa) and low temperature (−40∘C), characteristic of the environment inside the South Pole ice
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