Institution
Humboldt University of Berlin
Education•Berlin, Germany•
About: Humboldt University of Berlin is a education organization based out in Berlin, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 33671 authors who have published 61781 publications receiving 1908102 citations. The organization is also known as: Humboldt-Universität zu Berlin & Universitas Humboldtiana Berolinensis.
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TL;DR: In this paper, a wide range of commonly used CTLs, including various hole-transporting polymers, spiro-OMeTAD, metal oxides and fullerenes, were studied.
Abstract: Charge transport layers (CTLs) are key components of diffusion controlled perovskite solar cells, however, they can induce additional non-radiative recombination pathways which limit the open circuit voltage (VOC) of the cell. In order to realize the full thermodynamic potential of the perovskite absorber, both the electron and hole transport layer (ETL/HTL) need to be as selective as possible. By measuring the photoluminescence yield of perovskite/CTL heterojunctions, we quantify the non-radiative interfacial recombination currents in pin- and nip-type cells including high efficiency devices (21.4%). Our study comprises a wide range of commonly used CTLs, including various hole-transporting polymers, spiro-OMeTAD, metal oxides and fullerenes. We find that all studied CTLs limit the VOC by inducing an additional non-radiative recombination current that is in most cases substantially larger than the loss in the neat perovskite and that the least-selective interface sets the upper limit for the VOC of the device. Importantly, the VOC equals the internal quasi-Fermi level splitting (QFLS) in the absorber layer only in high efficiency cells, while in poor performing devices, the VOC is substantially lower than the QFLS. Using ultraviolet photoelectron spectroscopy and differential charging capacitance experiments we show that this is due to an energy level mis-alignment at the p-interface. The findings are corroborated by rigorous device simulations which outline important considerations to maximize the VOC. This work highlights that the challenge to suppress non-radiative recombination losses in perovskite cells on their way to the radiative limit lies in proper energy level alignment and in suppression of defect recombination at the interfaces.
457 citations
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TL;DR: In vitro induced LPS tolerance looks like the ex vivo LPS hyporesponsiveness of monocytes from septic patients with fatal outcome: downregulation of LPS-induced TNF-alpha and IL-10 production but not of IL-1RA secretion.
Abstract: Tolerance of monocytes/macrophages to endotoxin (lipopolysaccharide [LPS]) can be induced both in vivo and in vitro by LPS itself. Exposure to LPS, even at a very low dose, induces a downregulation of cytokine response to a second high dose LPS challenge. To learn more about the unknown mechanisms of this phenomenon, we studied the role of antiinflammatory cytokines in this process. Preculture of human peripheral blood monocytes for 24 hours with low concentrations of LPS induced hyporesponsiveness to high-dose LPS rechallenge with respect to tumor necrosis factor (TNF) alpha and interleukin (IL) 10 but not IL-1RA production. These results suggest that LPS tolerance reflects a functional switch of monocytes rather than a general LPS hyporesponsiveness. IL-10 and transforming growth factor (TGF) beta 1 showed additive effects in replacing LPS for induction of LPS hyporesponsiveness in vitro. Additionally, neutralizing anti-IL-10 and anti-TGF-beta monoclonal antibodies prevented induction of LPS tolerance. In vitro induced LPS tolerance looks like the ex vivo LPS hyporesponsiveness of monocytes from septic patients with fatal outcome: downregulation of LPS-induced TNF-alpha and IL-10 production but not of IL-1RA secretion. LPS hyporesponsiveness in septic patients was preceded by expression of IL-10 at both the mRNA and protein level. In summary, our data suggests that IL-10 and TGF-beta mediate the phenomenon of LPS tolerance in vitro and perhaps in vivo (septic patients), too.
456 citations
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TL;DR: Vascular lesion development initiated by endothelial cell damage is moderated by bone marrow–derived progenitor cells, and 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibition promotes bone marrow-dependent reendothelialization and diminishes vascular lesionDevelopment.
Abstract: Objective— Atherosclerosis and restenosis after vascular injury are both characterized by endothelial dysfunction, apoptosis, inappropriate endothelialization, and neointimal formation. Bone marrow–derived endothelial progenitor cells have been implicated in neovascularization, resulting in adult blood vessel formation. Despite the anticipated stem cell plasticity, the role of bone marrow–derived endothelial progenitor cells has not been clarified in vascular lesion development. Methods and Results— We investigated vascular lesion formation in mice after transplantation of bone marrow transfected by means of retrovirus with enhanced green fluorescent protein. Carotid artery injury was induced, resulting in neointimal formation. Fluorescence microscopy and immunohistological analysis revealed that bone marrow–derived progenitor cells are involved in reendothelialization of the vascular lesions. Treatment with rosuvastatin (20 mg/kg body wt per day), a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibit...
456 citations
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Vienna University of Economics and Business1, Commonwealth Scientific and Industrial Research Organisation2, Eindhoven University of Technology3, University of Liechtenstein4, Polytechnic University of Milan5, IT University of Copenhagen6, University of Tartu7, Vienna University of Technology8, Technion – Israel Institute of Technology9, IBM10, Queensland University of Technology11, VU University Amsterdam12, University of Stuttgart13, University of Ulm14, University of Vienna15, North Carolina State University16, University of Copenhagen17, Technical University of Denmark18, Humboldt University of Berlin19, Hasso Plattner Institute20
TL;DR: In this paper, the challenges and opportunities of blockchain for business process management (BPM) are outlined and a summary of seven research directions for investigating the application of blockchain technology in the context of BPM are presented.
Abstract: Blockchain technology offers a sizable promise to rethink the way interorganizational business processes are managed because of its potential to realize execution without a central party serving as a single point of trust (and failure). To stimulate research on this promise and the limits thereof, in this article, we outline the challenges and opportunities of blockchain for business process management (BPM). We first reflect how blockchains could be used in the context of the established BPM lifecycle and second how they might become relevant beyond. We conclude our discourse with a summary of seven research directions for investigating the application of blockchain technology in the context of BPM.
456 citations
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TL;DR: The author hopes that the present discussion will reduce the danger of inappropriate use of the beauty of the instrument sometimes seduces an investigator to use it without any connection to the physical model.
Abstract: A particle's motion in crowded environments often exhibits anomalous diffusion, whose nature depends on the situation at hand and is formalized within different physical models. Thus, such environments may contain traps, labyrinthine paths or macromolecular structures, which the particles may be attached to. Physical assumptions are translated into mathematical models which often come with nice mathematical instruments for their description, e.g. fractional diffusion equations. The beauty of the instrument sometimes seduces an investigator to use it without any connection to the physical model. The author hopes that the present discussion will reduce the danger of such inappropriate use.
455 citations
Authors
Showing all 34115 results
Name | H-index | Papers | Citations |
---|---|---|---|
Karl J. Friston | 217 | 1267 | 217169 |
Peer Bork | 206 | 697 | 245427 |
Raymond J. Dolan | 196 | 919 | 138540 |
Stefan Schreiber | 178 | 1233 | 138528 |
Andreas Pfeiffer | 149 | 1756 | 131080 |
Thomas Hebbeker | 148 | 1984 | 114004 |
Thomas Lohse | 148 | 1237 | 101631 |
Jean Bousquet | 145 | 1288 | 96769 |
Hermann Kolanoski | 145 | 1279 | 96152 |
Josh Moss | 139 | 1019 | 89255 |
R. D. Kass | 138 | 1920 | 107907 |
W. Kozanecki | 138 | 1498 | 99758 |
U. Mallik | 137 | 1625 | 97439 |
C. Haber | 135 | 1507 | 98014 |
Christophe Royon | 134 | 1453 | 90249 |