Institution
University of Stuttgart
Education•Stuttgart, Germany•
About: University of Stuttgart is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Laser & Finite element method. The organization has 27715 authors who have published 56370 publications receiving 1363382 citations. The organization is also known as: Universität Stuttgart.
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TL;DR: The relationships of noninnocent ligand behavior with excited-state descriptions and perspectives regarding material properties and single-electron or multielectron reactivity are illustrated briefly.
Abstract: The potential of redox-active ligands to behave “noninnocently” in transition-metal coordination compounds is reflected with respect to various aspects and situations. These include the question of establishing “correct” oxidation states, the identification and characterization of differently charged radical ligands, the listing of structural and other consequences of ligand redox reactions, and the distinction between barrierless delocalized “resonance” cases Mn/Ln ↔ Mn+1Ln–1 versus separated valence tautomer equilibrium situations Mn/Ln ⇌ Mn+1Ln–1. Further ambivalence arises for dinuclear systems with radical bridge Mn(μ-L•)Mn versus mixed-valent alternatives Mn+1(μ-L–)Mn, for noninnocent ligand-bridged coordination compounds of higher nuclearity such as (μ3-L)M3, (μ4-L)M4, (μ-L)4M4, or coordination polymers. Conversely, the presence of more than one noninnocently behaving ligand at a single transition-metal site in situations such as Ln–M–Ln–1 or L•–M–L• may give rise to corresponding ligand-to-ligand ...
433 citations
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TL;DR: Land use intensity and soil type strongly affected AMF community composition as well as the presence and prevalence of many AM fungi, and future work should examine how the differences in AMF species compositions affect important ecosystem processes in different soils.
Abstract: The objective of this study was to test whether soil types can be characterized by their arbuscular mycorrhizal fungal (AMF) communities. To answer this question, a well-defined study area in the temperate climatic zone of Central Europe was chosen with a large spectrum of soils and parent materials. Representative soil samples were taken from three soil types (Cambisol, Fluvisol and Leptosol) at in total 16 sites differing in agricultural land use intensity (9 grasslands and 7 arable lands). AMF spores were isolated and morphologically identified directly from field soils and after reproduction in trap cultures. AMF diversity and community composition strongly depended on soil type and land use intensity, and several AMF species were characteristic for a specific soil type or a specific land use type and hence had a specific niche. In contrast, other AM fungi could be considered as ‘generalists’ as they were present in each soil type investigated, irrespective of land use intensity. An estimated 53% of the 61 observed AMF species could be classified as ‘specialists’ as (almost) exclusively found in specific soil types and/or under specific land use intensities; 28% appeared to be ‘generalists’ and 19% could not be classified. Plant species compositions (either natural or planted) had only a subordinate influence on the AMF communities. In conclusion, land use intensity and soil type strongly affected AMF community composition as well as the presence and prevalence of many AM fungi. Future work should examine how the differences in AMF species compositions affect important ecosystem processes in different soils and to which extent the loss of specific groups of AM fungi affect soil quality.
432 citations
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TL;DR: First applications such as the detection of proteins, the monitoring of dynamic processes, and hyperspectral infrared chemical imaging are discussed, demonstrating the sensitivity and broad applicability of resonant SEIRA.
Abstract: Infrared spectroscopy is a powerful tool widely used in research and industry for a label-free and unambiguous identification of molecular species. Inconveniently, its application to spectroscopic analysis of minute amounts of materials, for example, in sensing applications, is hampered by the low infrared absorption cross-sections. Surface-enhanced infrared spectroscopy using resonant metal nanoantennas, or short “resonant SEIRA”, overcomes this limitation. Resonantly excited, such metal nanostructures feature collective oscillations of electrons (plasmons), providing huge electromagnetic fields on the nanometer scale. Infrared vibrations of molecules located in these fields are enhanced by orders of magnitude enabling a spectroscopic characterization with unprecedented sensitivity. In this Review, we introduce the concept of resonant SEIRA and discuss the underlying physics, particularly, the resonant coupling between molecular and antenna excitations as well as the spatial extent of the enhancement and...
431 citations
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08 Nov 1998TL;DR: It is shown how iterative demapping reduces the bit error rate in conventional communication systems applying multilevel modulation combined with simple channel coding.
Abstract: Iterative decoding algorithms for spectrally efficient modulation have become a vital field of research in digital communications. We show how iterative demapping reduces the bit error rate in conventional communication systems applying multilevel modulation combined with simple channel coding. For this the soft demapping has to be modified in order to accept a priori information. The system can be regarded as a serially concatenated iterative decoding scheme whereby the inner decoder is replaced by the soft demapping device. A design rule based on mutual information to find the 'best' mapping is proposed. Numerical results are presented for 4-PAM and 16-QAM examples.
426 citations
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TL;DR: An odorant-induced, transient accumulation of cyclic AMP in isolated olfactory cilia from rats, and the generation of inositol trisphosphate in antennal preparations from insects are reported, both of which show subsecond time courses that are sufficiently rapid to mediate the odorants-regulated permeability of o aroma receptor cells.
Abstract: OLFACTORY transduction is thought to be mediated by a membrane-bound receptor protein initiating a multistep reaction cascade which ultimately leads to a depolarizing generator current1,2. There is considerable evidence for the involvement of adenylate cyclase in vertebrate olfactory transduction3–6, and some data indicate that phospholipase C may have a central role in insect olfaction7. However, one must show that odorants not only stimulate enzyme activity but also induce changes in concentrations of relevant second messengers. One important criterion for a candidate second messenger of chemo-electrical transduction is that its formation must precede the onset of the odorant-induced membrane permeability changes which proceed on a subsecond time-scale8. Here we report an odorant-induced, transient accumulation of cyclic AMP in isolated olfactory cilia from rats, and the generation of inositol trisphosphate in antennal preparations from insects, both of which show subsecond time courses that are sufficiently rapid to mediate the odorant-regulated permeability of olfactory receptor cells.
425 citations
Authors
Showing all 28043 results
Name | H-index | Papers | Citations |
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Yi Chen | 217 | 4342 | 293080 |
Robert J. Lefkowitz | 214 | 860 | 147995 |
Michael Kramer | 167 | 1713 | 127224 |
Andrew G. Clark | 140 | 823 | 123333 |
Stephen D. Walter | 112 | 513 | 57012 |
Fedor Jelezko | 103 | 413 | 42616 |
Ulrich Gösele | 102 | 603 | 46223 |
Dirk Helbing | 101 | 642 | 56810 |
Ioan Pop | 101 | 1370 | 47540 |
Niyazi Serdar Sariciftci | 99 | 591 | 54055 |
Matthias Komm | 99 | 832 | 43275 |
Hans-Joachim Werner | 98 | 317 | 48508 |
Richard R. Ernst | 96 | 352 | 53100 |
Xiaoming Sun | 96 | 382 | 47153 |
Feng Chen | 95 | 2138 | 53881 |