6,847 research outputs found

    Nuclear CaMKII enhances histone H3 phosphorylation and remodels chromatin during cardiac hypertrophy.

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    Calcium/calmodulin-dependent protein kinase II (CaMKII) plays a central role in pathological cardiac hypertrophy, but the mechanisms by which it modulates gene activity in the nucleus to mediate hypertrophic signaling remain unclear. Here, we report that nuclear CaMKII activates cardiac transcription by directly binding to chromatin and regulating the phosphorylation of histone H3 at serine-10. These specific activities are demonstrated both in vitro and in primary neonatal rat cardiomyocytes. Activation of CaMKII signaling by hypertrophic agonists increases H3 phosphorylation in primary cardiac cells and is accompanied by concomitant cellular hypertrophy. Conversely, specific silencing of nuclear CaMKII using RNA interference reduces both H3 phosphorylation and cellular hypertrophy. The hyper-phosphorylation of H3 associated with increased chromatin binding of CaMKII occurs at specific gene loci reactivated during cardiac hypertrophy. Importantly, H3 Ser-10 phosphorylation and CaMKII recruitment are associated with increased chromatin accessibility and are required for chromatin-mediated transcription of the Mef2 transcription factor. Unlike phosphorylation of H3 by other kinases, which regulates cellular proliferation and immediate early gene activation, CaMKII-mediated signaling to H3 is associated with hypertrophic growth. These observations reveal a previously unrecognized function of CaMKII as a kinase signaling to histone H3 and remodeling chromatin. They suggest a new epigenetic mechanism controlling cardiac hypertrophy

    Higher Dimensional Taub-NUTs and Taub-Bolts in Einstein-Maxwell Gravity

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    We present a class of higher dimensional solutions to Einstein-Maxwell equations in d-dimensions. These solutions are asymptotically locally flat, de-Sitter, or anti-de Sitter space-times. The solutions we obtained depend on two extra parameters other than the mass and the nut charge. These two parameters are the electric charge, q and the electric potential at infinity, V, which has a non-trivial contribution. We Analyze the conditions one can impose to obtain Taub-Nut or Taub-Bolt space-times, including the four-dimensional case. We found that in the nut case these conditions coincide with that coming from the regularity of the one-form potential at the horizon. Furthermore, the mass parameter for the higher dimensional solutions depends on the nut charge and the electric charge or the potential at infinity.Comment: 11 pages, LaTe

    Scale without Conformal Invariance at Three Loops

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    We carry out a three-loop computation that establishes the existence of scale without conformal invariance in dimensional regularization with the MS scheme in d=4-epsilon spacetime dimensions. We also comment on the effects of scheme changes in theories with many couplings, as well as in theories that live on non-conformal scale-invariant renormalization group trajectories. Stability properties of such trajectories are analyzed, revealing both attractive and repulsive directions in a specific example. We explain how our results are in accord with those of Jack & Osborn on a c-theorem in d=4 (and d=4-epsilon) dimensions. Finally, we point out that limit cycles with turning points are unlike limit cycles with continuous scale invariance.Comment: 21 pages, 3 figures, Erratum adde

    The non-Abelian gauge theory of matrix big bangs

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    We study at the classical and quantum mechanical level the time-dependent Yang-Mills theory that one obtains via the generalisation of discrete light-cone quantisation to singular homogeneous plane waves. The non-Abelian nature of this theory is known to be important for physics near the singularity, at least as far as the number of degrees of freedom is concerned. We will show that the quartic interaction is always subleading as one approaches the singularity and that close enough to t=0 the evolution is driven by the diverging tachyonic mass term. The evolution towards asymptotically flat space-time also reveals some surprising features.Comment: 29 pages, 8 eps figures, v2: minor changes, references added: v3 small typographical changes

    Domain wall-based spin-Hall nano-oscillators

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    In the last decade, two revolutionary concepts in nano magnetism emerged from research for storage technologies and advanced information processing. The first suggests the use of magnetic domain walls (DWs) in ferromagnetic nanowires to permanently store information in DW racetrack memories. The second proposes a hardware realisation of neuromorphic computing in nanomagnets using nonlinear magnetic oscillations in the GHz range. Both ideas originate from the transfer of angular momentum from conduction electrons to localised spins in ferromagnets, either to push data encoded in DWs along nanowires or to sustain magnetic oscillations in artificial neurones. Even though both concepts share a common ground, they live on very different time scales which rendered them incompatible so far. Here, we bridge both ideas by demonstrating the excitation of magnetic auto-oscillations inside nano-scale DWs using pure spin currents

    Kishk sa'eedi, intellectual property rights for the Egyptian producers and market access to the EU

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    A traditional fermented cereal-based food made from whole wheat and buttermilk, Kishk Sa'eedi (KS) of Egypt is a millennial food that is home produced in five Governorates of the south of Egypt. It is little known to Egyptians outside the limits of its production area, and in turn, nearly unheard of outside Egypt. Extensively investigated and researched within the European funded “AFTER” FP7 project (African Food Tradition rEvisited by Research) KS revealed appreciable marketable qualities as a safe food of high nutritive value with a long shelf life, a low cost source of quality proteins, as well as possessing certain health attributes. More importantly, it satisfies the passion (Egyptomania) of many westerners for products of ancient Egyptian origin. The challenge was how to manage the situation where the highly marketable product is also a staple food for the rural communities of the KS producing region where the prevailing poverty and undernutrition was aggravated by the three years of political strife following the 25 January 2011 revolution. The paper explains how a win win situation was reached whereby the AFTER project objective of benefiting the national and European food industry from new food processing technologies derived from African traditional foods is realized without depriving the poor KS producing communities from their lifeline. The weaknesses and gaps in the Egyptian laws and regulations and the absence of a national system for protection of cultural heritage and traditional knowledge are reviewed. The AFTER project results were instrumental in providing substantive support for initiation of measures to strengthen national intellectual property rights protection systems for the bearers of traditional knowledge and to guarantee their fair share of benefits and economic returns. (Texte intégral
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