A simple and versatile analytical approach for planar metamaterials

We present an analytical model which permits the calculation of effective material parameters for planar metamaterials consisting of arbitrary unit cells (metaatoms) formed by a set of straight wire sections of potentially different shape. The model takes advantage of resonant electric dipole oscillations in the wires and their mutual coupling. The pertinent form of the metaatom determines the actual coupling features. This procedure represents a kind of building block model for quite different metaatoms. Based on the parameters describing the individual dipole oscillations and their mutual coupling the entire effective metamaterial tensor can be determined. By knowing these parameters for a certain metaatom it can be systematically modified to create the desired features. Performing such modifications effective material properties as well as the far field intensities remain predictable. As an example the model is applied to reveal the occurrence of optical activity if the split ring resonator metaatom is modified to L- or S-shaped metaatoms.Comment: 5 figures, 1 tabl

Yeast XRS2 and human NBN gene: Experimental evidence for homology using codon optimized cDNA

The genes, XRS2 in Saccharomyces cerevisiae and NBN in mammals, have little sequence identity at the amino acid level. Nevertheless, they are both found together with MRE11 and RAD50 in a highly conserved protein complex which functions in the repair of DNA double-strand breaks. Here, we have examined the evolutionary and functional relationship of these two genes by cross-complementation experiments. These experiments necessitated sequence correction for specific codon usage before they could be successfully conducted. We present evidence that despite extreme sequence divergence nibrin can, at least partially, replace Xrs2 in the cellular DNA damage response, and Xrs2 is able to promote nuclear localization of MRE11 in NBS cells. We discuss that the extreme sequence divergence reflects a unique adaptive pressure during evolution related to the specific eukaryotic role for both Xrs2 and nibrin in the subcellular localisation of the DNA repair complex. This, we suggest, is of particular relevance when cells are infected by viruses. The conflict hypothesis of co-evolution of DNA repair genes and DNA viruses may thus explain the very low sequence identity of these two homologous genes

Qualification of silane coatings for the strength enhancement of concrete parts

In former own publications [2]..[6] it was shown, that high precision concrete parts are a reliable alternative to natural stone for machine base frames. Beside long-term stability, also a predictable and highly reproducible thermal behavior is required. One opportunity is the application of materials with identical thermal expansion coefficients and appropriate mechanical properties. Concrete is a promising material for the whole machine structure under these circumstances. In contrast to base frames, moving parts need to have a lightweight design thus requiring a high level of specific stiffness. Concrete with a specific stiffness close to steel is an interesting material for the design of movable components coming up with dynamic properties comparable to welded steel structures. Additionally a high material strength is needed in lightweight design. To guarantee reliability at the same level as steel or aluminum light-weight parts, the endurance strength of concrete parts has to be improved significantly

Bildung und Ermächtigung von Jugendlichen zur reflexiven Gestaltung digitaler Gesundheitstechnologien

Jugendliche beziehen eine Vielzahl an gesundheitsbezogenen Informationen von digitalen Technologien und aus sozialen Medien, wodurch wiederum ihr Gesundheitsverständnis beeinflusst wird. Sicherlich besitzen digitale Gesundheitstechnologien das Potential, Gesundheitsrisiken entgegenzuwirken. Allerdings wird darin oftmals ein eindimensionaler Gesundheitsbegriff gezeichnet, der Gesundheit auf wenige zu optimierende Körperfunktionen reduziert, um normativen Gesundheits- und Schönheitsidealen zu entsprechen. Da Jugendliche sich in einer besonders prägenden Phase ihres Lebens befinden, ergibt sich diesbezüglich eine pädagogische Verantwortung, die es auch im Setting Schule und insbesondere im Unterrichtsfach Sport wahrzunehmen gilt. Vor diesem Hintergrund wird in diesem Beitrag der Ansatz einer ganzheitlichen und kritischen digitalen Gesundheitsbildung vorgeschlagen und begründet. Bildung wird dabei nach Klafki als Fähigkeit zur Selbstbestimmung, Mitbestimmung und Solidarität verstanden. Fragestellungen im Zusammenspiel von Bildung, Healthismus und Computational Empowerment werden skizziert, die für einen partizipativen Forschungsansatz nutzbar gemacht werden könnten, um Jugendliche zur reflexiven Gestaltung digitaler Gesundheitstechnologien zu ermächtigen. (DIPF/Orig.

FOCAD loss impacts microtubule assembly, G2/M progression and patient survival in astrocytic gliomas

In search of novel genes associated with glioma pathogenesis, we have previously shown frequent deletions of the KIAA1797/FOCAD gene in malignant gliomas, and a tumor suppressor function of the encoded focadhesin impacting proliferation and migration of glioma cells in vitro and in vivo. Here, we examined an association of reduced FOCAD gene copy number with overall survival of patients with astrocytic gliomas, and addressed the molecular mechanisms that govern the suppressive effect of focadhesin on glioma growth. FOCAD loss was associated with inferior outcome in patients with isocitrate dehydrogenase 1 or 2 (IDH)-mutant astrocytic gliomas of WHO grades II-IV. Multivariate analysis considering age at diagnosis as well as IDH mutation, MGMT promoter methylation, and CDKN2A/B homozygous deletion status confirmed reduced FOCAD gene copy number as a prognostic factor for overall survival. Using a yeast two-hybrid screen and pull-down assays, tubulin beta-6 and other tubulin family members were identified as novel focadhesin-interacting partners. Tubulins and focadhesin co-localized to centrosomes where focadhesin was enriched in proximity to centrioles. Focadhesin was recruited to microtubules via its interaction partner SLAIN motif family member 2 and reduced microtubule assembly rates, possibly explaining the focadhesin-dependent decrease in cell migration. During the cell cycle, focadhesin levels peaked in G2/M phase and influenced time-dependent G2/M progression potentially via polo like kinase 1 phosphorylation, providing a possible explanation for focadhesin-dependent cell growth reduction. We conclude that FOCAD loss may promote biological aggressiveness and worsen clinical outcome of diffuse astrocytic gliomas by enhancing microtubule assembly and accelerating G2/M phase progression