1,444 research outputs found

    The Tale of the Three Brothers – Shh, Wnt, and Fgf during Development of the Thalamus

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    The thalamic complex is an essential part of the brain that requires a combination of specialized activities to attain its final complexity. In the following review we will describe the induction process of the mid-diencephalic organizer (MDO) where three different signaling pathways merge: Wnt, Shh, and Fgf. Here, we dissect the function of each signaling pathway in the thalamus in chronological order of their appearance. First we describe the Wnt mediated induction of the MDO and compartition of the caudal forebrain, then the Shh mediated determination of proneural gene expression before discussing recent progress in characterizing Fgf function during thalamus development. Then, we focus on transcription factors, which are regulated by these pathways and which play a pivotal role in neurogenesis in the thalamus. The three signaling pathways act together in a strictly regulated chronology to orchestrate the development of the entire thalamus

    "Re-educating" tumor-associated macrophages by targeting NF-kappaB

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    The nuclear factor kappaB (NF-kappaB) signaling pathway is important in cancer-related inflammation and malignant progression. Here, we describe a new role for NF-kappaB in cancer in maintaining the immunosuppressive phenotype of tumor-associated macrophages (TAMs). We show that macrophages are polarized via interleukin (IL)-1R and MyD88 to an immunosuppressive "alternative" phenotype that requires IkappaB kinase beta-mediated NF-kappaB activation. When NF-kappaB signaling is inhibited specifically in TAMs, they become cytotoxic to tumor cells and switch to a "classically" activated phenotype; IL-12(high), major histocompatibility complex II(high), but IL-10(low) and arginase-1(low). Targeting NF-kappaB signaling in TAMs also promotes regression of advanced tumors in vivo by induction of macrophage tumoricidal activity and activation of antitumor activity through IL-12-dependent NK cell recruitment. We provide a rationale for manipulating the phenotype of the abundant macrophage population already located within the tumor microenvironment; the potential to "re-educate" the tumor-promoting macrophage population may prove an effective and novel therapeutic approach for cancer that complements existing therapies

    Simulation of semiconductor detectors in 3D with SolidStateDetectors.jl

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    The open-source software package SolidStateDetectors.jl to calculate the fields and simulate the drifts of charge carriers in solid state detectors, together with the corresponding pulses, is introduced. The package can perform all calculations in full 3D while it can also make use of detector symmetries. The effect of the surroundings of a detector can also be studied. The package is programmed in the user friendly and performance oriented language Julia, such that 3D field calculations and drift simulations can be executed efficiently and in parallel. While all kinds of semiconductor devices can be simulated, special emphasis is put on germanium detectors. The verification of the package is shown for an n-type segmented point-contact germanium detector. Additional features of SolidStateDetectors.jl planned for the near future are listed.Comment: 21 pages, 9 figure

    Expression of the ggpPS gene for glucosylglycerol biosynthesis from Azotobacter vinelandii improves the salt tolerance of Arabidopsis thaliana

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    Many organisms accumulate compatible solutes in response to salt or desiccation stress. Moderate halotolerant cyanobacteria and some heterotrophic bacteria synthesize the compatible solute glucosylglycerol (GG) as their main protective compound. In order to analyse the potential of GG to improve salt tolerance of higher plants, the model plant Arabidopsis thaliana was transformed with the ggpPS gene from the γ-proteobacterium Azotobacter vinelandii coding for a combined GG-phosphate synthase/phosphatase. The heterologous expression of the ggpPS gene led to the accumulation of high amounts of GG. Three independent Arabidopsis lines showing different GG contents were characterized in growth experiments. Plants containing a low (1–2 μmol g−1 FM) GG content in leaves showed no altered growth performance under control conditions but an increased salt tolerance, whereas plants accumulating a moderate (2–8 μmol g−1 FM) or a high GG content (around 17 μmol g−1 FM) showed growth retardation and no improvement of salt resistance. These results indicate that the synthesis of the compatible solute GG has a beneficial effect on plant stress tolerance as long as it is accumulated to an extent that does not negatively interfere with plant metabolism

    Land-atmosphere feedbacks exacerbate concurrent soil drought and atmospheric aridity.

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    Compound extremes such as cooccurring soil drought (low soil moisture) and atmospheric aridity (high vapor pressure deficit) can be disastrous for natural and societal systems. Soil drought and atmospheric aridity are 2 main physiological stressors driving widespread vegetation mortality and reduced terrestrial carbon uptake. Here, we empirically demonstrate that strong negative coupling between soil moisture and vapor pressure deficit occurs globally, indicating high probability of cooccurring soil drought and atmospheric aridity. Using the Global Land Atmosphere Coupling Experiment (GLACE)-CMIP5 experiment, we further show that concurrent soil drought and atmospheric aridity are greatly exacerbated by land-atmosphere feedbacks. The feedback of soil drought on the atmosphere is largely responsible for enabling atmospheric aridity extremes. In addition, the soil moisture-precipitation feedback acts to amplify precipitation and soil moisture deficits in most regions. CMIP5 models further show that the frequency of concurrent soil drought and atmospheric aridity enhanced by land-atmosphere feedbacks is projected to increase in the 21st century. Importantly, land-atmosphere feedbacks will greatly increase the intensity of both soil drought and atmospheric aridity beyond that expected from changes in mean climate alone

    Field induced transitions in a kagome antiferromagnet

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    The thermal order by disorder effect in magnetic field is studied for a classical Heisenberg antiferromagnet on the kagome lattice. Using analytical arguments we predict a unique H-T phase diagram for this strongly frustrated magnet: states with a coplanar and a uniaxial triatic order parameters respectively at low and high magnetic fields and an incompressible collinear spin-liquid state at a one-third of the saturation field. We also present the Monte Carlo data which confirm existence of these phases.Comment: 4 pages, 2 figures, accepted versio

    Slow Relaxation of Spin Structure in Exotic Ferromagnetic Phase of Ising-like Heisenberg Kagome Antiferromagnets

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    In the corner-sharing lattice, magnetic frustration causes macroscopic degeneracy in the ground state, which prevents systems from ordering. However, if the ensemble of the degenerate configuration has some global structure, the system can have a symmetry breaking phenomenon and thus posses a finite temperature phase transition. As a typical example of such cases, the magnetic phase transition of the Ising-like Heisenberg antiferromagnetic model on the kagome lattice has been studied. There, a phase transition of the two-dimensional ferromagnetic Ising universality class occurs accompanying with the uniform spontaneous magnetization. Because of the macroscopic degeneracy in the ordered phase, the system is found to show an entropy-driven ordering process, which is quantitatively characterized by the number of ``weathervane loop''. We investigate this novel type of slow relaxation in regularly frustrated system.Comment: 4 pages, 6 figure

    Signature inversion in semi-decoupled bands: Residual interaction between h9/2 protons and i13/2 neutrons

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    Semi-decoupled bands based on the πh9/2 ⊗ vi13/2 configuration are observed in 162Tm,164Tm and 174Ta. Spins assigned to these bands imply an inversion of the expected signature splitting, which is interpreted as being the result of a residual proton-neutron interactionComisión Interministerial de Ciencia y Tecnología PB95-0533US Dept. of Energy DE-FGOS- 92ER4069
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