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    Photobiochemical changes in Chlorella g120 culture during trophic conversion (metabolic pathway shift) from heterotrophic to phototrophic growth regime

    , Article Journal of Applied Phycology ; Volume 32, Issue 5 , 2020 , Pages 2807-2818 Babaei, A ; Ranglová, K ; Malapascua, J. R ; Torzillo, G ; Shayegan, J ; Silva Benavides, A. M ; Masojídek, J ; Sharif University of Technology
    Springer Science and Business Media B.V  2020
    Abstract
    Physiological and photobiochemical changes and growth in the heterotrophic strain Chlorella vulgaris g120 were studied during trophic conversion from heterotrophic to phototrophic growth regime. After the exposure of the Chlorella g120 culture to light, it revealed a significant activity of the electron transport (450–700 μmol e− m−2 s−1 as measured by chlorophyll fluorescence) and high PSII photochemical yield Fv/Fm between 0.7 and 0.8. Fast fluorescence induction kinetics showed that PSII electron acceptors in the plastoquinone pool remained partly oxidized, indicating no downregulation of PSII electron transport. The data further revealed that high photobiochemical activity is lost in... 

    A Survey on Electronic Structure of the Chlorophyll Molecules Participating in Photosynthesis Process

    , M.Sc. Thesis Sharif University of Technology Mazarei, Mahmood (Author) ; Vesaghi, Mohammad Ali (Supervisor)
    Abstract
    Optimized structure of the chlorophyll a and b molecules was obtained for LDA and GGA approximation by SIESTA package. Calculation illustrate that tails are curved in the optimized structure for both chlorophyll a and chlorophyll b molecules; in addition, Antennas, which are attached to the head of molecules, are located in optimized-spatial state. This optimized structure of chlorophyll a is similar to the calculated structure in ref [42]. Electrical dipole are calculated from ground state electron density of chlorophylls. Total electrical dipole of chlorophyll a for GGA and LDA approximation are 4.662 and 4.813 Debay, and these value for chlorophyll b are 1.435 and 1.302 Debay,... 

    Effects of Non-Markovian dynamics on the Energy Transport Processes in a Quantum Network

    , M.Sc. Thesis Sharif University of Technology Ranjbar Choubeh, Reza (Author) ; Rezakhani, Ali (Supervisor)
    Abstract
    In this thesis we are going to study the effects of Non-Markovianity on the excitation energy transport(EET) and compare it with Markovian effects. We will see that the shape of a network affects its efficiency. The speed of EET in linear networks is slowed down as Non-Markovianity is increased and this in turn lowers the efficiency of linear networks in Non-Markovian regime. Finally, we compare the efficiency of different networks  

    An investigation into the energy transfer efficiency of a two-pigment photosynthetic system using a macroscopic quantum model

    , Article BioSystems ; Volume 197 , 2020 Ghasemi, F ; Shafiee, A ; Sharif University of Technology
    Elsevier Ireland Ltd  2020
    Abstract
    Despite several different measures of efficiency that are applicable to the photosynthetic systems, a precise degree of efficiency of these systems is not completely determined. Introducing an efficient model for the dynamics of light-harvesting complexes in biological environments is a major purpose in investigating such systems. Here, we investigate the effect of macroscopic quantum behavior of a system of two pigments on the transport phenomena in this system model which interacts with an oscillating environment. We use the second-order perturbation theory to calculate the time-dependent population of excitonic states of a two-dimensional Hamiltonian using a non-master equation approach.... 

    The effect of different light intensities and light/dark regimes on the performance of photosynthetic microalgae microbial fuel cell

    , Article Bioresource Technology ; Volume 261 , 2018 , Pages 350-360 ; 09608524 (ISSN) Bazdar, E ; Roshandel, R ; Yaghmaei, S ; Mardanpour, M. M ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    This study develops a photosynthetic microalgae microbial fuel cell (PMMFC) engaged Chlorella vulgaris microalgae to investigate effect of light intensities and illumination regimes on simultaneous production of bioelectricity, biomass and wastewater treatment. The performance of the system under different light intensity (3500, 5000, 7000 and 10,000 lx) and light/dark regimes (24/00, 12/12, 16/8 h) was investigated. The optimum light intensity and light/dark regimes for achieving maximum yield of PMMFC were obtained. The maximum power density of 126 mW m−3, the coulombic efficiency of 78% and COD removal of 5.47% were achieved. The maximum biomass concentration of 4 g l−1 (or biomass yield... 

    Correlation between concentrations of chlorophyll-a and satellite derived climatic factors in the Persian Gulf

    , Article Marine Pollution Bulletin ; Volume 161, Part A , December , 2020 Moradi, M ; Moradi, N ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Monthly mean satellite derived Chl-a, aerosols, wind, SST, PAR, and turbidity datasets were used to investigate the possible factors regulating phytoplankton variability in the Persian Gulf. The spatial correlation analysis revealed two distinct regions of SST and PAR, and a relatively uniform spatial correlation pattern of the other parameters. The cross correlation between aeolian dusts and Chl-a was significantly positive with 1–3 months offset. The pattern of spatial correlation between Chl-a and SST was positive in the shallow regions without time lag, and was negative with time offset of 3–5 months in deeper regions. The cross correlation between Chl-a and north-ward winds were... 

    Light harvesting and photocurrent generation by nanostructured photoelectrodes sensitized with a photosynthetic pigment: A new application for microalgae

    , Article Bioresource Technology ; Volume 163 , July , 2014 , Pages 1-5 ; ISSN: 09608524 Mohammadpour, R ; Janfaza, S ; Abbaspour Aghdam, F ; Sharif University of Technology
    Abstract
    Here in this study, successful conversion of visible light into electricity has been achieved through utilizing microalgal pigments as a sensitizer of nanostructured photo-electrode of dye-sensitized solar cells (DSSCs). For the first time, photosynthetic pigments extracted from microalgae grown in wastewater is employed to imitate photosynthesis process in bio-molecule-sensitized solar cells. Two designs of photoanode were employed: 10μm nanoparticular TiO2 electrode and 20μm long self-ordered, vertically oriented nanotube arrays of titanium dioxide films. Microalgal photosynthetic pigments are loaded on nanostructured electrodes and their photovoltaic performances have been investigated....