Response of Chlamydomonas Reinhardtii Reaction Center Stoichiometry to Light Intensity Variation: A Spectroscopic and Lds-Page Analysis

1987 ◽  
pp. 355-358
Author(s):  
Patrick J. Neale ◽  
Anastasios Melis
Keyword(s):  
Light Intensity ◽  
Chlamydomonas Reinhardtii ◽  
Reaction Center ◽  
Intensity Variation

Susceptibility of LED street lamps to voltage dips

2020 ◽  
Vol 52 (8) ◽  
pp. 1040-1056
Author(s):  
S Sakar ◽  
A Bagheri ◽  
S Rönnberg ◽  
MHJ Bollen
Keyword(s):  
High Pressure ◽  
Light Intensity ◽  
Performance Metrics ◽  
Intensity Variation ◽  
Individual Characteristics ◽  
Unintended Consequences ◽  
Residual Voltage ◽  
Voltage Dips ◽  
Light Flicker ◽  
High Pressure Sodium Lamp

There is an ongoing transition from high-pressure sodium lamps to LED street lamps that offer higher efficiency, cost saving and better photometric performance. This transition could lead to unintended consequences such as light flicker and extinguishing in street lighting applications when they are exposed to voltage dips. The goal of this paper is to analyse the light intensity variation of various street lamps when they are exposed to voltage dips. Several performance metrics for quantifying immunity of lamps have been proposed. Values for these metrics are obtained by applying artificial voltage dips to lamps. For voltage dips with residual voltage above 38%, lamps are immune in terms of a short-term light flicker metric. For residual voltage above 25%, light intensity reduces but without extinguishing. Compared to an incandescent lamp and high-pressure sodium lamp, LED street lamps exhibit longer zero-light intensity duration. Most of the studied LED street lamps exhibit uncoordinated light intensity drops, i.e. longer or shifted, with respect to the applied voltage dip. Individual characteristics of LED street lamps require testing before installation to prevent unexpected consequences. Recommendations are given for standardisation committees to implement an assessment method for lighting equipment.

Recognition algorithm for light intensity variation of LED lamps using neural network with statistics characteristics

Optik ◽  
2020 ◽  
Vol 200 ◽  
pp. 163362 ◽  
Author(s):  
Fukang Sun ◽  
Jianxia Xie ◽  
Qiansheng Fang ◽  
Xinxin Zhuo
Keyword(s):  
Neural Network ◽  
Light Intensity ◽  
Intensity Variation ◽  
Recognition Algorithm

Chlamydomonas reinhardtii: duration of its cell cycle and phases at growth rates affected by light intensity

Planta ◽  
2010 ◽  
Vol 233 (1) ◽  
pp. 75-86 ◽  
Author(s):  
Milada Vítová ◽  
Kateřina Bišová ◽  
Dáša Umysová ◽  
Monika Hlavová ◽  
Shigeyuki Kawano ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Light Intensity ◽  
Chlamydomonas Reinhardtii ◽  
Growth Rates

Excitation pressure regulates the activation energy for recombination events in the photosystem II reaction centres of Chlamydomonas reinhardtii

2007 ◽  
Vol 85 (6) ◽  
pp. 721-729 ◽  
Author(s):  
Tessa Pocock ◽  
P. V. Sane ◽  
S. Falk ◽  
N. P.A. Hüner
Keyword(s):  
Activation Energy ◽  
Photosystem Ii ◽  
Redox Potential ◽  
Chlamydomonas Reinhardtii ◽  
Reaction Center ◽  
Growth Conditions ◽  
High Irradiance ◽  
Reaction Centres ◽  
Excitation Pressure

Using in vivo thermoluminescence, we examined the effects of growth irradiance and growth temperature on charge recombination events in photosystem II reaction centres of the model green alga Chlamydomonas reinhardtii. We report that growth at increasing irradiance at either 29 or 15 °C resulted in comparable downward shifts in the temperature peak maxima (TM) for S2QB– charge pair recombination events, with minimal changes in S2QA– recombination events. This indicates that such growth conditions decrease the activation energy required for S2QB– charge pair recombination events with no concomitant change in the activation energy for S2QA– recombination events. This resulted in a decrease in the ΔTM between S2QA– and S2QB– recombination events, which was reversible when shifting cells from low to high irradiance and back to low irradiance at 29 °C. We interpret these results to indicate that the redox potential of QB was modulated independently of QA, which consequently narrowed the redox potential gap between QA and QB in photosystem II reaction centres. Since a decrease in the ΔTM between S2QA– and S2QB– recombination events correlated with growth at increasing excitation pressure, we conclude that acclimation to growth under high excitation pressure narrows the redox potential gap between QA and QB in photosystem II reaction centres, enhancing the probability for reaction center quenching in C. reinhardtii. We discuss the molecular basis for the modulation of the redox state of QB, and suggest that the potential for reaction center quenching complements antenna quenching via the xanthophyll cycle in the photoprotection of C. reinhardtii from excess light.

The effect of light intensity on hydrogen production by sulfur-deprived Chlamydomonas reinhardtii

2004 ◽  
Vol 114 (1-2) ◽  
pp. 143-151 ◽  
Author(s):  
Tatyana Laurinavichene ◽  
Irena Tolstygina ◽  
Anatoly Tsygankov
Keyword(s):  
Hydrogen Production ◽  
Light Intensity ◽  
Chlamydomonas Reinhardtii ◽  
Effect Of Light
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