763 research outputs found

    Reduced Coulomb interaction in organic solar cells by the introduction of inorganic high-k nanostructured materials

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    In this article a concept is introduced, which allows for reduced Coulomb interaction in organic solar cells and as such for enhanced power conversion efficiencies. The concept is based on the introduction of electrically insulating, nanostructured high-k materials into the organic matrix, which do not contribute to the charge transport, however, effectively enhance the permittivity of the organic active layer and thereby reduce the Coulomb interaction. Using an analytical model it is demonstrated that even at a distance of 20 nm to the organic / inorganic interface of the nanostructure, the Coulomb interaction can be reduced by more than 15 %. The concept is implemented using P3HT:PCBM solar cells with integrated high-k nanoparticles (strontium titanate). It could be demonstrated that in comparison to a reference cell without integrated nanoparticles, the power conversion efficiencies could be improved by ~20 %.Comment: 11 pages, 7 figure

    Scalable Unseparated Bioelectrochemical Reactors by Using a Carbon Fiber Brush as Stirrer and Working Electrode

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    The concept of energy conversion into platform chemicals using bioelectrochemical systems (BES) has gained increasing attention in recent years, as the technology simultaneously provides an opportunity for sustainable chemical production and tackles the challenge of Power-to-X technologies. There are many approaches to realize the industrial scale of BES. One concept is to equip standard bioreactors with static electrodes. However, large installations resulted in a negative influence on various reactor parameters. In this study, we present a new single-chamber BES based on a stirred tank reactor in which the stirrer was replaced by a carbon fiber brush, performing the functions of the working electrode and the stirrer. The reactor is characterized in abiotic studies and electro-fermentations with Clostridium acetobutylicum. Compared to standard reactors an increase in butanol production of 20.14±3.66 % shows that the new BES can be efficiently used for bioelectrochemical processes

    The Radial Wave Operator in Similarity Coordinates

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    We present a rigorous functional analytic setting to study the radial wave equation in similarity coordinates. As an application we analyse linear stability of the fundamental self--similar solution of the wave equation with a focusing power nonlinearity.Comment: Minor corrections in order to match the published versio

    The Effect of Tiotropium in Symptomatic Asthma Despite Low- to Medium-Dose Inhaled Corticosteroids: A Randomized Controlled Trial.

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    BackgroundTiotropium, a once-daily long-acting anticholinergic bronchodilator, has demonstrated efficacy in patients with asthma who were symptomatic despite treatment with medium- to high-dose inhaled corticosteroids (ICS).ObjectiveThe objective of this study was to evaluate the efficacy and safety of once-daily tiotropium Respimat (5 ÎŒg or 2.5 ÎŒg), compared with placebo Respimat, as add-on therapy to low- to medium-dose ICS for adults with symptomatic asthma.MethodsA phase III, double-blind, placebo-controlled trial was conducted (NCT01316380). Adults with symptomatic asthma receiving low- to medium-dose ICS (200-400 ÎŒg budesonide or equivalent dose) and a pre-bronchodilator forced expiratory volume in 1 second (FEV1) ≄60% and ≀90% of predicted normal were randomized to 12 weeks of treatment with once-daily tiotropium Respimat 5 ÎŒg or 2.5 ÎŒg, or placebo Respimat, as add-on therapy to ICS. The primary endpoint was peak FEV1(0-3h) response.ResultsIn total, 464 patients were randomized (61% female; mean age 43 years; mean baseline FEV1 78% of predicted normal). After 12 weeks, both tiotropium Respimat doses were superior to placebo (adjusted mean difference from placebo: 5 ÎŒg, 128 mL; 2.5 ÎŒg, 159 mL; both P < .001). Both doses of tiotropium Respimat were also superior to placebo with regard to the secondary endpoints of adjusted mean trough FEV1 and FEV1 area under the curve(0-3h) responses, and the other endpoints of morning and evening peak expiratory flow. Adverse events were comparable across the treatment groups.ConclusionsOnce-daily tiotropium Respimat add-on therapy to low- to medium-dose ICS in adults with symptomatic asthma is an efficacious bronchodilator, and its safety and tolerability are comparable with those of placebo Respimat

    The Checkpoint Regulator SLAMF3 Preferentially Prevents Expansion of Auto-Reactive B Cells Generated by Graft-vs.-Host Disease

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    Absence of the mouse cell surface receptor SLAMF3 in SLAMF3-/- mice suggested that this receptor negatively regulates B cell homeostasis by modulating activation thresholds of B cell subsets. Here, we examine whether anti-SLAMF3 affects both B and T cell subsets during immune responses to haptenated ovalbumin [NP-OVA] and in the setting of chronic graft vs. host disease (cGVHD) induced by transferring B6.C-H2 bm12/KhEg (bm12) CD4+ T cells into B6 WT mice. We find that administering αSLAMF3 to NP-OVA immunized B6 mice primarily impairs antibody responses and Germinal center B cell [GC B] numbers, whilst CXCR5+, PD-1+, and ICOS+ T follicular helper (TFH) cells are not significantly affected. By contrast, administering αSLAMF3 markedly enhanced autoantibody production upon induction of cGVHD by the transfer of bm12 CD4+ T cells into B6 recipients. Surprisingly, αSLAMF3 accelerated both the differentiation of GC B and donor-derived TFH cells initiated by cGVHD. The latter appeared to be induced by decreased numbers of donor-derived Treg and T follicular regulatory (TFR) cells. Collectively, these data show that control of anti-SLAMF3-induced signaling is requisite to prevent autoantibody responses during cGVHD, but reduces responses to foreign antigens

    The cytoplasmic domain of the AAA+ protease FtsH is tilted with respect to the membrane to facilitate substrate entry

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    AAA+ proteases are degradation machines that use ATP hydrolysis to unfold protein substrates and translocate them through a central pore toward a degradation chamber. FtsH, a bacterial membrane-anchored AAA+ protease, plays a vital role in membrane protein quality control. How substrates reach the FtsH central pore is an open key question that is not resolved by the available atomic structures of cytoplasmic and periplasmic domains. In this work, we used both negative stain TEM and cryo-EM to determine 3D maps of the full-length Aquifex aeolicus FtsH protease. Unexpectedly, we observed that detergent solubilization induces the formation of fully active FtsH dodecamers, which consist of two FtsH hexamers in a single detergent micelle. The striking tilted conformation of the cytosolic domain in the FtsH dodecamer visualized by negative stain TEM suggests a lateral substrate entrance between the membrane and cytosolic domain. Such a substrate path was then resolved in the cryo-EM structure of the FtsH hexamer. By mapping the available structural information and structure predictions for the transmembrane helices to the amino acid sequence we identified a linker of ∌20 residues between the second transmembrane helix and the cytosolic domain. This unique polypeptide appears to be highly flexible and turned out to be essential for proper functioning of FtsH as its deletion fully eliminated the proteolytic activity of FtsH
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