Institution
Martin Luther University of Halle-Wittenberg
Education•Halle, Germany•
About: Martin Luther University of Halle-Wittenberg is a education organization based out in Halle, Germany. It is known for research contribution in the topics: Population & Liquid crystal. The organization has 20232 authors who have published 38773 publications receiving 965004 citations. The organization is also known as: MLU & University of Wittenberg.
Papers published on a yearly basis
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TL;DR: The results challenge the traditional view regarding the fate and role of lignin during litter decomposition and suggest that bioavailable, soluble compounds became a limiting factor for CO2 production.
Abstract: Lignin is a main component of plant litter. Its degradation is thought to be critical for litter decomposition rates and the build-up of soil organic matter. We studied the relationships between lignin degradation and the production of dissolved organic carbon (DOC) and of CO2 during litter decomposition. Needle or leaf litter of five species (Norway spruce, Scots pine, mountain ash, European beech, sycamore maple) and of different decomposition stage (freshly fallen and up to 27 months of field exposure) was incubated in the laboratory for two years. Lignin degradation was followed with the CuO method. Strong lignin degradation occurred during the first 200 incubation days, as revealed by decreasing yields of lignin-derived phenols. Thereafter lignin degradation leveled off. This pattern was similar for fresh and decomposed litter, and it stands in contrast to the common view of limited lignin degradation in fresh litter. Dissolved organic carbon and CO2 also peaked in the first period of the incubation but were not interrelated. In the later phase of incubation, CO2 production was positively correlated with DOC amounts, suggesting that bioavailable, soluble compounds became a limiting factor for CO2 production. Lignin degradation occurred only when CO2 production was high, and not limited by bioavailable carbon. Thus carbon availability was the most important control on lignin degradation. In turn, lignin degradation could not explain differences in DOC and CO2 production over the study period. Our results challenge the traditional view regarding the fate and role of lignin during litter decomposition. Lignin degradation is controlled by the availability of easily decomposable carbon sources. Consequently, it occurs particularly in the initial phase of litter decomposition and is hampered at later stages if easily decomposable resources decline.
234 citations
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TL;DR: Numerical simulations of compromised healing situations showed that the establishment of a vascular network in response to angiogenic growth factors is a key factor in the healing process and a correct description of cell migration is shown to be essential to the prediction of realistic spatiotemporal tissue distribution patterns in the fracture callus.
234 citations
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TL;DR: The data support a dose-dependent induction of proatherosclerotic oxidative stress in human endothelial cells in response to Ang II, and the expression of NAD(P)H oxidase subunit gp91-phox is critical for endothelial superoxide anion formation.
Abstract: Objective— Angiotensin II (Ang II)–mediated induction of vascular superoxide anion formation could contribute to the development of endothelial dysfunction, hypertension, and atherosclerosis. An NAD(P)H oxidase has been identified as a major endothelial source of superoxide anions. However, the molecular mechanism underlying the regulation of NAD(P)H oxidase activity in response to Ang II is not well understood. Methods and Results— We investigated the dose-dependent regulation of superoxide anion formation and of NAD(P)H oxidase subunit expression in response to Ang II in human endothelial cells. Ang II regulates superoxide anion formation and the limiting subunit of endothelial NAD(P)H oxidase, gp91-phox, in a dose-dependent manner via Ang II type 1 (AT 1 ) receptor–mediated induction and Ang II type 2 receptor–mediated partial inhibition at higher Ang II concentrations. Furthermore, AT 1 receptor blocker therapy before coronary bypass surgery downregulates the gp91-phox expression in internal mammary artery biopsies of patients with coronary artery disease. Conclusions— Our data support a dose-dependent induction of proatherosclerotic oxidative stress in human endothelial cells in response to Ang II. The expression of NAD(P)H oxidase subunit gp91-phox is critical for endothelial superoxide anion formation. AT 1 receptor blockade has an antiatherosclerotic and antioxidative potential by the reduction of oxidative stress in the vessel wall.
234 citations
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TL;DR: It is demonstrated that plakophilin 2 can interact directly with several desmosomal components, including desmoplakin, plakoglobin, desmoglein 1 and 2, and desmocollin 1a and 2a, and is able to associate with β-catenin through its head domain, and the expression of plakophon 2 in SW480 cells up-regulates the endogenous β- catenin/T cell factor-signaling activity.
234 citations
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TL;DR: In this article, the authors derived the bosonic part of the four-dimensional low energy effective action and showed that it is a non-canonical N=2 supergravity which includes a massive two-form.
Abstract: Compactifications of type II theories on Calabi-Yau threefolds including electric and magnetic background fluxes are discussed. We derive the bosonic part of the four-dimensional low energy effective action and show that it is a non-canonical N=2 supergravity which includes a massive two-form. The symplectic invariance of the theory is maintained as long as the flux parameters transform as a symplectic vector and a massive two-form which couples to both electric and magnetic field strengths is present. The mirror symmetry between type IIA and type IIB compactified on mirror manifolds is shown to hold for R-R fluxes at the level of the effective action. We also compactify type IIA in the presence of NS three-form flux but the mirror symmetry in this case remains unclear.
233 citations
Authors
Showing all 20466 results
Name | H-index | Papers | Citations |
---|---|---|---|
Niels Birbaumer | 142 | 835 | 77853 |
Michael Schmitt | 134 | 2007 | 114667 |
Niels E. Skakkebæk | 127 | 596 | 59925 |
Stefan D. Anker | 117 | 415 | 104945 |
Pedro W. Crous | 115 | 809 | 51925 |
Eric Verdin | 115 | 370 | 47971 |
Bernd Nilius | 112 | 496 | 44812 |
Josep Tabernero | 111 | 803 | 68982 |
Hans-Dieter Volk | 107 | 784 | 46622 |
Dan Rujescu | 106 | 552 | 60406 |
John I. Nurnberger | 105 | 522 | 51402 |
Ulrich Gösele | 102 | 603 | 46223 |
Wolfgang J. Parak | 102 | 469 | 43307 |
Martin F. Bachmann | 100 | 415 | 34124 |
Munir Pirmohamed | 97 | 675 | 39822 |