The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
V V Eremin - One of the best experts on this subject based on the ideXlab platform.
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Protein Vibration Effects on Primary Electron Transfer Dynamics in Rhodobacter sphaeroides Photosynthetic Reaction Center
Journal of Physical Chemistry B, 2017Co-Authors: Vladimir V Poddubnyy, I O Glebov, V V EreminAbstract:Primary electron transfer (ET) in the chromophore subsystem in a bacterial reaction center (RC) is a unique process, and is coupled with the protein motion, which, like the ET, is caused by photoexcitation of these chromophores. ET is also coupled with dissipative processes, which are caused by interaction between chromophores and vibrations of its surrounding protein. We propose a new dynamics calculation method that accounts for both these effects of protein vibrations. Within this method, the photoinduced protein motion causes an addition of Coherent Component to the ET rate. We performed dynamics calculation using this method and parameters, which were determined from the ab initio wave functions of the chromophore subsystem and protein normal vibrational modes. We showed that it is this protein motion that causes oscillations in the time-dependencies of stimulated emission intensities and of absorption at 1020 nm. Moreover, the latter oscillations are related to the Coherent Component of the ET rate.
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Protein Vibration Effects on Primary Electron Transfer Dynamics in Rhodobacter sphaeroides Photosynthetic Reaction Center
Journal of Physical Chemistry B, 2017Co-Authors: Vladimir V Poddubnyy, I O Glebov, V V EreminAbstract:Primary electron transfer (ET) in the chromophore subsystem in a bacterial reaction center (RC) is a unique process, and is coupled with the protein motion, which, like the ET, is caused by photoexcitation of these chromophores. ET is also coupled with dissipative processes, which are caused by interaction between chromophores and vibrations of its surrounding protein. We propose a new dynamics calculation method that accounts for both these effects of protein vibrations. Within this method, the photoinduced protein motion causes an addition of Coherent Component to the ET rate. We performed dynamics calculation using this method and parameters, which were determined from the ab initio wave functions of the chromophore subsystem and protein normal vibrational modes. We showed that it is this protein motion that causes oscillations in the time-dependencies of stimulated emission intensities and of absorption at 1020 nm. Moreover, the latter oscillations are related to the Coherent Component of the ET rate.
Jean-louis Martin - One of the best experts on this subject based on the ideXlab platform.
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Electrochromic Detection of a Coherent Component in the Formation of the Charge Pair P+HL- in Bacterial Reaction Centers†
Biochemistry, 2000Co-Authors: Marten H. Vos, Christian Rischel, Michael R. Jones, Jean-louis MartinAbstract:We demonstrate coupling of an intraprotein electron transfer reaction to Coherent vibrational motions. The kinetics of charge separation toward the radical pair state P+HL- were studied in reaction centers of Rhodobacter sphaeroides at 15 K. The electrochromic shift of the bacteriochlorophyll monomers is the most prominent spectral feature associated with this charge displacement. The newly reported absolute absorption spectrum of the P+HL- state is discussed in terms of this shift. In wild-type reaction centers, the rise kinetics of the electrochromic shift display a small but significant 30 cm-1 periodic modulation (period of ∼1 ps). This modulation is also present in FL181Y mutant reaction centers, where overall charge separation is somewhat more rapid than in the wild-type reaction center. In contrast, in YM210L mutant reaction centers, where the charge separation is much slower, the modulation is absent. The conclusion that the motion along the reaction coordinate has a 30 cm-1 Coherent Component is ...
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Electrochromic detection of a Coherent Component in the formation of the charge pair P+H(L)- in bacterial reaction centers
Biochemistry, 2000Co-Authors: Marten Vos, Christian Rischel, Michael R. Jones, Jean-louis MartinAbstract:We demonstrate coupling of an intraprotein electron transfer reaction to Coherent vibrational motions. The kinetics of charge separation toward the radical pair state P+H(L)- were studied in reaction centers of Rhodobacter sphaeroides at 15 K. The electrochromic shift of the bacteriochlorophyll monomers is the most prominent spectral feature associated with this charge displacement. The newly reported absolute absorption spectrum of the P+H(L)- state is discussed in terms of this shift. In wild-type reaction centers, the rise kinetics of the electrochromic shift display a small but significant 30 cm-1 periodic modulation (period of ~1 ps). This modulation is also present in FL181Y mutant reaction centers, where overall charge separation is somewhat more rapid than in the wild-type reaction center. In contrast, in YM210L mutant reaction centers, where the charge separation is much slower, the modulation is absent. The conclusion that the motion along the reaction coordinate has a 30 cm-1 Coherent Component is discussed in light of possible mechanisms of electron transfer.
Vladimir V Poddubnyy - One of the best experts on this subject based on the ideXlab platform.
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Protein Vibration Effects on Primary Electron Transfer Dynamics in Rhodobacter sphaeroides Photosynthetic Reaction Center
Journal of Physical Chemistry B, 2017Co-Authors: Vladimir V Poddubnyy, I O Glebov, V V EreminAbstract:Primary electron transfer (ET) in the chromophore subsystem in a bacterial reaction center (RC) is a unique process, and is coupled with the protein motion, which, like the ET, is caused by photoexcitation of these chromophores. ET is also coupled with dissipative processes, which are caused by interaction between chromophores and vibrations of its surrounding protein. We propose a new dynamics calculation method that accounts for both these effects of protein vibrations. Within this method, the photoinduced protein motion causes an addition of Coherent Component to the ET rate. We performed dynamics calculation using this method and parameters, which were determined from the ab initio wave functions of the chromophore subsystem and protein normal vibrational modes. We showed that it is this protein motion that causes oscillations in the time-dependencies of stimulated emission intensities and of absorption at 1020 nm. Moreover, the latter oscillations are related to the Coherent Component of the ET rate.
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Protein Vibration Effects on Primary Electron Transfer Dynamics in Rhodobacter sphaeroides Photosynthetic Reaction Center
Journal of Physical Chemistry B, 2017Co-Authors: Vladimir V Poddubnyy, I O Glebov, V V EreminAbstract:Primary electron transfer (ET) in the chromophore subsystem in a bacterial reaction center (RC) is a unique process, and is coupled with the protein motion, which, like the ET, is caused by photoexcitation of these chromophores. ET is also coupled with dissipative processes, which are caused by interaction between chromophores and vibrations of its surrounding protein. We propose a new dynamics calculation method that accounts for both these effects of protein vibrations. Within this method, the photoinduced protein motion causes an addition of Coherent Component to the ET rate. We performed dynamics calculation using this method and parameters, which were determined from the ab initio wave functions of the chromophore subsystem and protein normal vibrational modes. We showed that it is this protein motion that causes oscillations in the time-dependencies of stimulated emission intensities and of absorption at 1020 nm. Moreover, the latter oscillations are related to the Coherent Component of the ET rate.
Apostolos Papageorgiou - One of the best experts on this subject based on the ideXlab platform.
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Residual slip of sliding blocks induced by near-fault ground motions
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS, 2017Co-Authors: Kristel Carolina Meza Fajardo, Apostolos PapageorgiouAbstract:The response of a rigid block supported on a horizontally moving foundation through a dry-friction contact is investigated to near-fault ground motions. Such motions can be thought of as consisting of a Coherent Component (pulse') and an inCoherent Component, which can be described as a band-limited random noise'. The equation of motion of this strongly nonlinear system is reduced to a normalized form that reveals important parameters of the problem such as the critical acceleration ratio. The response of the sliding block to a set of uniformly processed near-fault motions, covering a sufficiently wide range of magnitudes, is evaluated numerically for selected discrete values of the acceleration ratio. For each value of the critical acceleration ratio, the numerically computed residual slips are fitted with a Weibull (Gumbel type III) extreme value probability distribution. This allows the establishment of regression equations that describe accurately design sliding curves corresponding to various levels of non-exceedance probability. The analysis reveals that the Coherent Component of motion contributes significantly to the response of the sliding block. Furthermore, the relevant acceleration in specifying the critical acceleration ratio is the (normalized) amplitude, (H_pulse), of the pulse and not the (normalized) amplitude of the inCoherent Component (H). Finally, the inCoherent Component is described quantitatively in terms of the root-mean-square acceleration a(RMS), and an attempt is made to understand its influence on the response of the sliding block.
Apostolos S. Papageorgiou - One of the best experts on this subject based on the ideXlab platform.
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Residual slip of sliding blocks induced by near‐fault ground motions
Earthquake Engineering & Structural Dynamics, 2016Co-Authors: Kristel C. Meza Fajardo, Apostolos S. PapageorgiouAbstract:Summary The response of a rigid block supported on a horizontally moving foundation through a dry-friction contact is investigated to near-fault ground motions. Such motions can be thought of as consisting of a Coherent Component (‘pulse’) and an inCoherent Component, which can be described as a band-limited ‘random noise’. The equation of motion of this strongly nonlinear system is reduced to a normalized form that reveals important parameters of the problem such as the critical acceleration ratio. The response of the sliding block to a set of uniformly processed near-fault motions, covering a sufficiently wide range of magnitudes, is evaluated numerically for selected discrete values of the acceleration ratio. For each value of the critical acceleration ratio, the numerically computed residual slips are fitted with a Weibull (Gumbel type III) extreme value probability distribution. This allows the establishment of regression equations that describe accurately design sliding curves corresponding to various levels of non-exceedance probability. The analysis reveals that the Coherent Component of motion contributes significantly to the response of the sliding block. Furthermore, the relevant acceleration in specifying the critical acceleration ratio is the (normalized) amplitude, αH_pulse, of the pulse and not the (normalized) amplitude of the inCoherent Component αH. Finally, the inCoherent Component is described quantitatively in terms of the root-mean-square acceleration aRMS, and an attempt is made to understand its influence on the response of the sliding block. Copyright © 2016 John Wiley & Sons, Ltd.