Energy transfer within phycocyanin trimers of Mastigocladus laminosus studied by picosecond time-resolved transient absorption spectroscopy

The transient absorption recovery induced in phycocyanin trimers by picosecond pulses of variable wavelength (570 — 620 nm) has been recorded and analyzed by applying a least-squares multi-exponential fit procedure. The results suggest that in native PC trimers the chromophores exhibit a microheterogeneity with the effect that the derived apparent lifetimes are functions of excitation and probing wavelength. It is suggested that, due to strong excitonic coupling between a-84 and ß-84 chromophores, the lifetime of the terminal acceptor state is reduced to about 900 ps; the apparent energy transfer time from chromophore β-155 to a-84 and ß-84 chromophores varies between 20—50 ps depending on the actual chromophore-protein arrangement (microheterogeneity)

Integration of Multifidelity Multidisciplinary Computer Codes for Design and Analysis of Supersonic Aircraft

This paper documents the development of a conceptual level integrated process for design and analysis of efficient and environmentally acceptable supersonic aircraft. To overcome the technical challenges to achieve this goal, a conceptual design capability which provides users with the ability to examine the integrated solution between all disciplines and facilitates the application of multidiscipline design, analysis, and optimization on a scale greater than previously achieved, is needed. The described capability is both an interactive design environment as well as a high powered optimization system with a unique blend of low, mixed and high-fidelity engineering tools combined together in the software integration framework, ModelCenter. The various modules are described and capabilities of the system are demonstrated. The current limitations and proposed future enhancements are also discussed

Picosecond time-resolved fluorescence of phycobiliproteins

The α- and β-subunits of C-phycocyanin from Mastigocladus laminosus were prepared according to revised procedures. Both subunits are isolated as dimers, which can be dissociated into monomers with detergent mixtures. The fluorescence decay kinetics are similar for the respective monomers and dimers. In no case could they be fitted by only one (α-subunit) or two exponentials (β-subunit) which are predicted by theory for samples with a unique chromophore—protein arrangement containing one and two chromophores, respectively. It is suggested that there exists a heterogeneity among the chromophores of the subunits, which may persist in the highly aggregated complexes present in cyanobacterial antennas

Numerical Construction of LISS Lyapunov Functions under a Small Gain Condition

In the stability analysis of large-scale interconnected systems it is frequently desirable to be able to determine a decay point of the gain operator, i.e., a point whose image under the monotone operator is strictly smaller than the point itself. The set of such decay points plays a crucial role in checking, in a semi-global fashion, the local input-to-state stability of an interconnected system and in the numerical construction of a LISS Lyapunov function. We provide a homotopy algorithm that computes a decay point of a monotone op- erator. For this purpose we use a fixed point algorithm and provide a function whose fixed points correspond to decay points of the monotone operator. The advantage to an earlier algorithm is demonstrated. Furthermore an example is given which shows how to analyze a given perturbed interconnected system.Comment: 30 pages, 7 figures, 4 table