The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Jurgen Manfred Knott - One of the best experts on this subject based on the ideXlab platform.
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biosynthesis of long chain polyamines by crenarchaeal polyamine synthases from hyperthermus butylicus and pyrobaculum aerophilum
FEBS Letters, 2009Co-Authors: Jurgen Manfred KnottAbstract:Polyamines are ubiquitously present in all organisms. In addition to the common polyamines, thermophilic archaea synthesize long-chain polyamines. In the present study polyamine synthases from Hyperthermus butylicus and Pyrobaculum aerophilum were cloned and their substrate specificity was analyzed. The polyamine synthase HbSpeE II from H. butylicus synthesized long-chain polyamines with high activity using the same mechanism that is used by a wide range of organisms to synthesize common polyamines, in which the aminopropyl residue derives from decarboxylated S-adenosylmethionine. This is the first polyamine synthase described that synthesizes a polyamine longer than a tetramine with high activity.
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Biosynthesis of long‐chain polyamines by crenarchaeal polyamine synthases from Hyperthermus butylicus and Pyrobaculum aerophilum
FEBS Letters, 2009Co-Authors: Jurgen Manfred KnottAbstract:Polyamines are ubiquitously present in all organisms. In addition to the common polyamines, thermophilic archaea synthesize long-chain polyamines. In the present study polyamine synthases from Hyperthermus butylicus and Pyrobaculum aerophilum were cloned and their substrate specificity was analyzed. The polyamine synthase HbSpeE II from H. butylicus synthesized long-chain polyamines with high activity using the same mechanism that is used by a wide range of organisms to synthesize common polyamines, in which the aminopropyl residue derives from decarboxylated S-adenosylmethionine. This is the first polyamine synthase described that synthesizes a polyamine longer than a tetramine with high activity.
M. Nakagawa - One of the best experts on this subject based on the ideXlab platform.
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a new pll frequency Synthesizer with high switching speed
IEEE Transactions on Vehicular Technology, 1992Co-Authors: A. Kajiwara, M. NakagawaAbstract:A phase-locked loop (PLL) frequency Synthesizer with high switching speed is proposed. Mobile communication networks are evolving towards microcellulars operating in narrowband TDMA and microwave bands to meet the rapidly increasing demands for both voice and data services. Therefore, Synthesizers with high switching speed are required for the realization. However, it will be difficult for conventional Synthesizers to provide switching times of shorter than 1 ms. The PLL Synthesizer proposed is composed entirely of digital signal processors except for a voltage-controlled oscillator (VCO). The VCO control signal is derived by the subtraction of the linear reference phase and the feedback phase; therefore, it does not need the band-limited loop filter which limits the ability of the loop to switch fast. The experimental results show that it can provide switching times as short as 0.1 ms, which is 10/sup 2/ approximately 10/sup 3/ times higher than conventional PLL Synthesizers, and spurs of less than -60 dB. >
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a new pll frequency Synthesizer with high switching speed
Global Communications Conference, 1992Co-Authors: A. Kajiwara, M. NakagawaAbstract:In this paper, a new phase-locked loop (PLL) frequency Synthesizer with high switching speed is proposed, and the experimental and theoretical results are given. Mobile communication networks are evolving towards micro cellulars operating in narrowband TDMA and microwave bands to meet the rapidly increasing demands for both voice and data services. Therefore, Synthesizers with high switching speed are required for the realization. However, it will be difficult for conventional Synthesizers to provide the switching time of shorter than 1 ms. The PLL Synthesizer proposed here is composed entirely of digital signal processors except for a voltage-controlled oscillator (VCO)
Thomas Wiegand - One of the best experts on this subject based on the ideXlab platform.
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Depth Image-Based Rendering With Advanced Texture Synthesis for 3-D Video
IEEE Transactions on Multimedia, 2011Co-Authors: Patrick Ndjiki-nya, Philipp Merkle, H. Lakshman, Dimitar Doshkov, Moshe Koppel, K Müller, Thomas WiegandAbstract:A depth image-based rendering (DIBR) approach with advanced inpainting methods is presented. The DIBR algorithm can be used in 3-D video applications to synthesize a number of different perspectives of the same scene, e.g., from a multiview-video-plus-depth (MVD) representation. This MVD format consists of video and depth sequences for a limited number of original camera views of the same natural scene. Here, DIBR methods allow the computation of additional new views. An inherent problem of the view synthesis concept is the fact that image information which is occluded in the original views may become visible, especially in extrapolated views beyond the viewing range of the original cameras. The presented algorithm synthesizes these occluded textures. The Synthesizer achieves visually satisfying results by taking spatial and temporal consistency measures into account. Detailed experiments show significant objective and subjective gains of the proposed method in comparison to the state-of-the-art methods.
M. U. Khan - One of the best experts on this subject based on the ideXlab platform.
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Lipid metabolism in leaves of an 18:4-plant, Echium plantagineum : a model of galactolipid biosynthesis in 18:3- and 18:4-plants
Plant Physiology and Biochemistry, 1996Co-Authors: J. P. Williams, M. U. KhanAbstract:All of the major leaf glycerolipids of Echium plantagineum, a member of the Boraginaceae, contain two unusual fatty acids, γ-linolenic acid (γ18 :3) and octadecatetraenoic acid (18 :4). γ18 :3 is synthesized by an ω12-desaturation of linoleic acid (18 :2) in cytosolic phosphatidylcholine (PC) ; 18 :4 is synthesized by an further desaturation of α-linolenic acid (α18 :3) and/or γ18 :3. The positional distribution of γ18 :3 and 18 :4, and a comparison of the fatty acid molecular species composition of the major leaf glycerolipids were used to show that each of the chloroplast glycerolipids is synthesized from different diacylglycerol (DAG) precursors. Our results show that (a) the bulk of the chloroplastic monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) are synthesized by separate pathways from different cytosolic pools of precursor DAG, and (b) the DAG backbone of sulfoquinovosyldiacylglycerol (SQDG) is derived from cytosolic precursor(s) in a pathway similar to the bulk MGDG. A comparison of lipid metabolism in 18 :4-plants with 16 :3- and 18 :3-plants has led us to propose a new model for the biosynthesis of MGDG, DGDG and SQDG in 18 :3- and 18 :4-plants. In this model there are three pathways of biosynthesis in each type of plant ; two pathways, in association with the inner envelope membrane, synthesize the majority of MGDG and SQDG, while a separate pathway in the outer envelope synthesizes predominantly DGDG.
A. Kajiwara - One of the best experts on this subject based on the ideXlab platform.
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a new pll frequency Synthesizer with high switching speed
IEEE Transactions on Vehicular Technology, 1992Co-Authors: A. Kajiwara, M. NakagawaAbstract:A phase-locked loop (PLL) frequency Synthesizer with high switching speed is proposed. Mobile communication networks are evolving towards microcellulars operating in narrowband TDMA and microwave bands to meet the rapidly increasing demands for both voice and data services. Therefore, Synthesizers with high switching speed are required for the realization. However, it will be difficult for conventional Synthesizers to provide switching times of shorter than 1 ms. The PLL Synthesizer proposed is composed entirely of digital signal processors except for a voltage-controlled oscillator (VCO). The VCO control signal is derived by the subtraction of the linear reference phase and the feedback phase; therefore, it does not need the band-limited loop filter which limits the ability of the loop to switch fast. The experimental results show that it can provide switching times as short as 0.1 ms, which is 10/sup 2/ approximately 10/sup 3/ times higher than conventional PLL Synthesizers, and spurs of less than -60 dB. >
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a new pll frequency Synthesizer with high switching speed
Global Communications Conference, 1992Co-Authors: A. Kajiwara, M. NakagawaAbstract:In this paper, a new phase-locked loop (PLL) frequency Synthesizer with high switching speed is proposed, and the experimental and theoretical results are given. Mobile communication networks are evolving towards micro cellulars operating in narrowband TDMA and microwave bands to meet the rapidly increasing demands for both voice and data services. Therefore, Synthesizers with high switching speed are required for the realization. However, it will be difficult for conventional Synthesizers to provide the switching time of shorter than 1 ms. The PLL Synthesizer proposed here is composed entirely of digital signal processors except for a voltage-controlled oscillator (VCO)
