Institution
Free University of Berlin
Education•Berlin, Germany•
About: Free University of Berlin is a education organization based out in Berlin, Germany. It is known for research contribution in the topics: Population & Context (language use). The organization has 35195 authors who have published 66525 publications receiving 2094403 citations. The organization is also known as: FU Berlin.
Topics: Population, Context (language use), Excited state, Receptor, Politics
Papers published on a yearly basis
Papers
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TL;DR: In this article, the authors used tungsten-stabilized Ni-rich cathode materials to increase the energy density of Li ion batteries without compromising the battery's durability.
Abstract: Development of advanced high energy density lithium ion batteries is important for promoting electromobility. Making electric vehicles attractive and competitive compared to conventional automobiles depends on the availability of reliable, safe, high power, and highly energetic batteries whose components are abundant and cost effective. Nickel rich Li[NixCoyMn1−x−y]O2 layered cathode materials (x > 0.5) are of interest because they can provide very high specific capacity without pushing charging potentials to levels that oxidize the electrolyte solutions. However, these cathode materials suffer from stability problems. We discovered that doping these materials with tungsten (1 mol%) remarkably increases their stability due to a partial layered to cubic (rock salt) phase transition. We demonstrate herein highly stable Li ion battery prototypes consisting of tungsten-stabilized Ni rich cathode materials (x > 0.9) with specific capacities >220 mA h g-1. This development can increase the energy density of Li ion batteries more than 30% above the state of the art without compromising durability.
277 citations
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TL;DR: The potential of modern XANES theory is demonstrated by presenting first simulations of the dichroism in the XANes spectra of the PSII manganese complex.
Abstract: X-ray absorption spectroscopy (XAS) has become a prominent tool for the element-specific analysis of transition metals at the catalytic center of metalloenzymes. In the present study the information content of X-ray spectra with respect to the nuclear geometry and, in particular, to the electronic structure of the protein-bound metal ions is explored using the manganese complex of photosystem II (PSIII) as a model system. The EXAFS range carries direct information on the number and distances of ligands as well as on the chemical type of the ligand donor function. For first-sphere ligands and second-sphere metals (in multinuclear complexes), the determination of precise distances is mostly straightforward, whereas the determination of coordination numbers clearly requires more effort. The EXAFS section starts with an exemplifying discussion of a PSII spectrum data set with focus on the coordination number problem. Subsequently, the method of linear dichroism EXAFS spectroscopy is introduced and it is shown how the EXAFS data leads to an atomic resolution model for the tetra-manganese complex of PSII. In the XANES section the following aspects are considered: (1) Alternative approaches are evaluated for determination of the metal-oxidation state by comparison with a series of model compounds. (2) The interpretation of XANES spectra in terms of molecular orbitals (MOs) is approached by comparative multiple-scattering calculations and MO calculations. (3) The underlying reasons for the oxidation-state dependence of the XANES spectra are explored. Furthermore, the potential of modern XANES theory is demonstrated by presenting first simulations of the dichroism in the XANES spectra of the PSII manganese complex.
277 citations
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TL;DR: Ultrashort, high-power laser pulses propagating vertically in the atmosphere have been observed over more than 20 km using an imaging 2-m astronomical telescope, bearing evidence for whole-beam parallelization about the nonlinear focus.
Abstract: Ultrashort, high-power laser pulses propagating vertically in the atmosphere have been observed over more than 20 km using an imaging 2-m astronomical telescope. This direct observation in several wavelength bands shows indications for filament formation at distances as far as 2 km in the atmosphere. Moreover, the beam divergence at 5 km altitude is smaller than expected, bearing evidence for whole-beam parallelization about the nonlinear focus. We discuss implications for white-light Lidar applications.
277 citations
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TL;DR: The czc-encoded protein complex CzcABC was shown to be a zinc-proton antiporter that mediates resistance to Co2+, Zn2+, and Cd2+ in Alcaligenes eutrophus by cation efflux by using everted membrane vesicles of Escherichia coli and an acridine orange fluorescence quenching assay.
Abstract: The function of the CzcABC protein complex, which mediates resistance to Co2+, Zn2+, and Cd2+ in Alcaligenes eutrophus by cation efflux, was investigated by using everted membrane vesicles of Escherichia coli and an acridine orange fluorescence quenching assay. Since metal cation uptake could not be measured with inside-out membrane vesicles prepared from A. eutrophus and since available E. coli strains did not express the Czc-mediated resistance to cobalt, zinc, and cadmium salts, mutants of E. coli which exhibited a Czc-dependent increase in heavy metal resistance were isolated. E. coli mutant strain EC351 constitutively accumulated Co2+, Zn2+, and Cd2+. In the presence of Czc, net uptake of these heavy metal cations was reduced to the wild-type level. Inside-out vesicles prepared from E. coli EC351 cells displayed a Czc-dependent uptake of Co2+, Zn2+, and Cd2+ and a cation-triggered acridine orange fluorescence increase. The czc-encoded protein complex CzcABC was shown to be a zinc-proton antiporter.
277 citations
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TL;DR: Molecular profiling in two Hodgkin's disease cell lines identified 45 genes whose expression in both cell lines was regulated by constitutive nuclear nuclear nuclear factor (NF)-κB, and found 17 novel NF-κB target genes.
Abstract: Constitutive nuclear nuclear factor (NF)-κB activity is observed in a variety of hematopoietic and solid tumors. Given the distinctive role of constitutive NF-κB for Hodgkin and Reed-Sternberg (HRS) cell viability, we performed molecular profiling in two Hodgkin's disease (HD) cell lines to identify NF-κB target genes. We recognized 45 genes whose expression in both cell lines was regulated by NF-κB. The NF-κB–dependent gene profile comprises chemokines, cytokines, receptors, apoptotic regulators, intracellular signaling molecules, and transcription factors, the majority of which maintain a marker-like expression in HRS cells. Remarkably, we found 17 novel NF-κB target genes. Using chromatin immunoprecipitation we demonstrate that NF-κB is recruited directly to the promoters of several target genes, including signal transducer and activator of transcription (STAT)5a, interleukin-13, and CC chemokine receptor 7. Intriguingly, NF-κB positively regulates STAT5a expression and signaling pathways in HRS cells, and promotes its persistent activation. In fact, STAT5a overexpression was found in most tumor cells of tested patients with classical HD, indicating a critical role for HD. The gene profile underscores a central role of NF-κB in the pathogenesis of HD and potentially of other tumors with constitutive NF-κB activation.
277 citations
Authors
Showing all 35717 results
Name | H-index | Papers | Citations |
---|---|---|---|
Andreas Pfeiffer | 149 | 1756 | 131080 |
Nicholas A. Peppas | 141 | 825 | 90533 |
Robert H. Purcell | 139 | 666 | 70366 |
Andrea Castro | 132 | 1500 | 90019 |
Klaus Ley | 129 | 495 | 57964 |
Klaus-Robert Müller | 129 | 764 | 79391 |
Britton Chance | 128 | 1112 | 76591 |
Stefan H. E. Kaufmann | 126 | 925 | 58891 |
Thomas F. Tedder | 123 | 426 | 48374 |
Aravinda Chakravarti | 120 | 451 | 99632 |
Jerome Ritz | 120 | 644 | 47987 |
Thomas C. Quinn | 120 | 827 | 65881 |
Angela D. Friederici | 120 | 701 | 50191 |
E. K. U. Gross | 119 | 1154 | 75970 |
Alexander Rich | 115 | 539 | 50171 |